================================================================== 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 ffff888037aaf880 by task syz.1.4548/21939 CPU: 1 UID: 0 PID: 21939 Comm: syz.1.4548 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: __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+0xc3/0x110 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: 0033:0x7f1ee959e0d9 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:00007f1eea391028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007f1ee9825fa0 RCX: 00007f1ee959e0d9 RDX: 0000000000000041 RSI: 0000000000040280 RDI: 00002000000003c0 RBP: 00007f1ee9635024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1ee9826038 R14: 00007f1ee9825fa0 R15: 00007fff90b19f38 Allocated by task 21901: 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 21943: 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 ffff888037aaf880 which belongs to the cache kmalloc-16 of size 16 The buggy address is located 0 bytes inside of freed 16-byte region [ffff888037aaf880, ffff888037aaf890) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888037aaf8a0 pfn:0x37aaf flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000200 ffff88813fe21640 ffffea0000d18250 ffffea0000aaad50 raw: ffff888037aaf8a0 000000080080006b 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5604, tgid 5604 (syz-executor), ts 609985681970, free_ts 609985141606 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] __do_kmalloc_node mm/slub.c:5333 [inline] __kvmalloc_node_noprof+0x793/0x970 mm/slub.c:6905 xt_jumpstack_alloc net/netfilter/x_tables.c:1449 [inline] do_replace_table+0x1c5/0x760 net/netfilter/x_tables.c:1486 xt_replace_table+0x2e/0x130 net/netfilter/x_tables.c:1545 __do_replace+0x1cf/0x990 net/ipv4/netfilter/arp_tables.c:922 do_replace net/ipv6/netfilter/ip6_tables.c:1156 [inline] do_ip6t_set_ctl+0xa5f/0xd00 net/ipv6/netfilter/ip6_tables.c:1643 nf_setsockopt+0x8d/0xf0 net/netfilter/nf_sockopt.c:101 ipv6_setsockopt+0x135/0x170 net/ipv6/ipv6_sockglue.c:970 tcp_setsockopt+0xa7/0x100 net/ipv4/tcp.c:4179 do_sock_setsockopt+0xf3/0x1d0 net/socket.c:2368 __sys_setsockopt+0x195/0x220 net/socket.c:2393 page last free pid 5604 tgid 5604 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 ___free_pages_bulk mm/kasan/shadow.c:333 [inline] __kasan_populate_vmalloc_do mm/kasan/shadow.c:385 [inline] __kasan_populate_vmalloc+0x164/0x210 mm/kasan/shadow.c:424 kasan_populate_vmalloc include/linux/kasan.h:580 [inline] alloc_vmap_area+0x95d/0x2bb0 mm/vmalloc.c:2145 __get_vm_area_node+0x1ca/0x330 mm/vmalloc.c:3248 __vmalloc_node_range_noprof+0x228/0x1630 mm/vmalloc.c:4064 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4165 xt_counters_alloc+0x4c/0x70 net/netfilter/x_tables.c:1474 __do_replace+0x97/0x990 net/ipv4/netfilter/arp_tables.c:904 do_replace net/ipv6/netfilter/ip6_tables.c:1156 [inline] do_ip6t_set_ctl+0xa5f/0xd00 net/ipv6/netfilter/ip6_tables.c:1643 nf_setsockopt+0x8d/0xf0 net/netfilter/nf_sockopt.c:101 ipv6_setsockopt+0x135/0x170 net/ipv6/ipv6_sockglue.c:970 tcp_setsockopt+0xa7/0x100 net/ipv4/tcp.c:4179 do_sock_setsockopt+0xf3/0x1d0 net/socket.c:2368 __sys_setsockopt+0x195/0x220 net/socket.c:2393 __do_sys_setsockopt net/socket.c:2399 [inline] __se_sys_setsockopt net/socket.c:2396 [inline] __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2396 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 Memory state around the buggy address: ffff888037aaf780: fa fb fc fc 00 00 fc fc fa fb fc fc fa fb fc fc ffff888037aaf800: 00 01 fc fc fa fb fc fc fa fb fc fc fa fb fc fc >ffff888037aaf880: fa fb fc fc fa fb fc fc fa fb fc fc 00 00 fc fc ^ ffff888037aaf900: 00 00 fc fc 00 00 fc fc fa fb fc fc 00 00 fc fc ffff888037aaf980: 00 03 fc fc 00 00 fc fc 00 00 fc fc fa fb fc fc ==================================================================