KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show

Status: upstream: reported on 2026/08/14 00:03
Subsystems: usb
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+2280f1cca5e6b0c353e4@syzkaller.appspotmail.com
First crash: 8d15h, last: 1d14h
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ID Workflow Result Correct Bug Created Started Finished Revision
a4ec77a6 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show 2026/08/11 00:36 2026/08/11 00:36 2026/08/11 01:32 039457bd
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] usb: gadget: f_midi2: fix use-after-free in string attribute show path 2 (2) 2026/08/16 10:40
[syzbot] [usb?] KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show 0 (1) 2026/08/14 00:03

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23200 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23201 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 1 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23202 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 2 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23203 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 3 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23204 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 4 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23205 by task syz.6.1510/13744

CPU: 0 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 5 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23206 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 6 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23207 by task syz.6.1510/13744

CPU: 0 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 7 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23208 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faae4f9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faae5f43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faae5225fa0 RCX: 00007faae4f9e0d9
RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0
RBP: 00007faae5035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faae5226038 R14: 00007faae5225fa0 R15: 00007ffe77c23248
 </TASK>

Allocated by task 13715:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5471
 __kmemdup_nul mm/util.c:64 [inline]
 kstrndup+0x64/0x120 mm/util.c:120
 f_midi2_opts_str_store.constprop.0+0xbf/0x240 drivers/usb/gadget/function/f_midi2.c:2205
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13749:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 f_midi2_opts_str_store.constprop.0+0xf0/0x240 drivers/usb/gadget/function/f_midi2.c:2211
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88807de23200
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 freed 32-byte region [ffff88807de23200, ffff88807de23220)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807de23b40 pfn:0x7de23
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88813fe24780 ffffea0001d8b190 ffffea0000aa16d0
raw: ffff88807de23b40 0000000800400028 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5241, tgid 5241 (v4l_id), ts 49415292769, free_ts 49385581831
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 slab_free_hook mm/slub.c:2629 [inline]
 slab_free mm/slub.c:6377 [inline]
 kmem_cache_free+0x412/0x6b0 mm/slub.c:6504
 file_free fs/file_table.c:104 [inline]
 __fput_deferred+0x3e9/0x4a0 fs/file_table.c:567
 fput_close+0x118/0x250 fs/file_table.c:629
 path_openat+0x1417/0x4280 fs/namei.c:4872
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 4982 tgid 4982 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 __pagetable_free include/linux/mm.h:3695 [inline]
 pagetable_free include/linux/mm.h:3719 [inline]
 pagetable_dtor_free include/linux/mm.h:3818 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:221 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x2cf/0x380 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710

Memory state around the buggy address:
 ffff88807de23100: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff88807de23200: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                      ^
 ffff88807de23280: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff88807de23300: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:648 [inline]
BUG: KASAN: slab-use-after-free in string+0x471/0x4d0 lib/vsprintf.c:730
Read of size 1 at addr ffff88807de23209 by task syz.6.1510/13744

CPU: 1 UID: 0 PID: 13744 Comm: syz.6.1510 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 string_nocheck lib/vsprintf.c:648 [inline]
 string+0x471/0x4d0 lib/vsprintf.c:730
 vsnprintf+0x422/0x1300 lib/vsprintf.c:2945
 vscnprintf lib/vsprintf.c:3014 [inline]
 scnprintf+0xdb/0x150 lib/vsprintf.c:3067
 f_midi2_opts_str_show drivers/usb/gadget/function/f_midi2.c:2187 [inline]
 f_midi2_opts_iface_name_show+0x6e/0xa0 drivers/usb/gadget/function/f_midi2.c:2592
 fill_read_buffer fs/configfs/file.c:68 [inline]
 configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88
 __kernel_read+0x397/0xad0 fs/read_write.c:532
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
 ima_file_check+0xcc/0x120 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xc4/0x210 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x985/0x4280 fs/namei.c:4863
 do_file_open+0x20e/0x430 fs/namei.c:4892
 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_open fs/open.c:1382 [inline]
 __se_sys_open fs/open.c:1378 [inline]
 __x64_sys_open+0xfe/0x1d0 fs/open.c:1378
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/16 21:28 upstream dcb68831eac7 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/10 18:48 upstream db2ddb871435 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/10 12:19 upstream db2ddb871435 558388e4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/09 22:55 upstream b9b3e33b70b7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/09 22:25 upstream b9b3e33b70b7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/09 22:15 upstream b9b3e33b70b7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/09 20:54 upstream b9b3e33b70b7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/09 20:47 upstream b9b3e33b70b7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/09 20:44 upstream b643e495ae92 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/14 12:33 upstream 2f1baf1fc892 2cf1fbb7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
2026/08/10 19:47 linux-next 6b8c8af514d7 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in f_midi2_opts_iface_name_show
* Struck through repros no longer work on HEAD.