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

Status: premoderation: reported C repro on 2026/07/24 19:07
Reported-by: syzbot+9cee69321b78b280ac89@syzkaller.appspotmail.com
First crash: 12d, last: 11h45m
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/08/05 upstream (ToT) c21bb4193868 C [report] KASAN: slab-use-after-free Read in driver_deferred_probe_del
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in driver_deferred_probe_del 19 1 5d14h 5d14h 0/3 upstream: reported on 2026/07/31 05:09
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/08/05 14:30 tree origin lts running

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in list_empty include/linux/list.h:373 [inline]
BUG: KASAN: slab-use-after-free in driver_deferred_probe_del+0x78/0x240 drivers/base/dd.c:148
Read of size 8 at addr ffff888105a6b6a8 by task syz-executor303/323

CPU: 0 UID: 0 PID: 323 Comm: syz-executor303 Not tainted syzkaller #0 1c659cfea3877f078df945e50c8eb7045fd035a9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 print_address_description+0x71/0x210 mm/kasan/report.c:377
 print_report+0x4a/0x70 mm/kasan/report.c:481
 kasan_report+0x162/0x1a0 mm/kasan/report.c:594
 __asan_report_load8_noabort+0x18/0x20 mm/kasan/report_generic.c:381
 list_empty include/linux/list.h:373 [inline]
 driver_deferred_probe_del+0x78/0x240 drivers/base/dd.c:148
 device_del+0x593/0xcf0 drivers/base/core.c:3883
 usb_del_gadget+0x18f/0x200 drivers/usb/gadget/udc/core.c:1577
 usb_del_gadget_udc+0x19/0x30 drivers/usb/gadget/udc/core.c:1593
 dummy_udc_remove+0x5c/0x70 drivers/usb/gadget/udc/dummy_hcd.c:1123
 platform_remove+0x7e/0xb0 drivers/base/platform.c:1424
 device_remove drivers/base/dd.c:567 [inline]
 __device_release_driver drivers/base/dd.c:1272 [inline]
 device_release_driver_internal+0x4ad/0x830 drivers/base/dd.c:1295
 device_driver_detach+0x3f/0x50 drivers/base/dd.c:1331
 unbind_store+0x1ab/0x1f0 drivers/base/bus.c:244
 drv_attr_store+0x91/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0x141/0x160 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x316/0x510 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x762/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fc34475abf9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffebbb6f408 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffebbb6f440 RCX: 00007fc34475abf9
RDX: 000000000000000b RSI: 0000200000000400 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000000f4240 R09: 00000000000f4240
R10: 00000000000f4240 R11: 0000000000000246 R12: 00000000000f4240
R13: 0000000000000002 R14: 00007ffebbb6f42c R15: 00007ffebbb6f430
 </TASK>

Allocated by task 321:
 kasan_save_stack mm/kasan/common.c:49 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
 kasan_save_alloc_info+0x3a/0x50 mm/kasan/generic.c:565
 poison_kmalloc_redzone mm/kasan/common.c:379 [inline]
 __kasan_kmalloc+0x96/0xb0 mm/kasan/common.c:396
 kasan_kmalloc include/linux/kasan.h:261 [inline]
 __kmalloc_cache_noprof+0x23c/0x470 mm/slub.c:4426
 kmalloc_noprof include/linux/slab.h:881 [inline]
 kzalloc_noprof include/linux/slab.h:1017 [inline]
 device_private_init drivers/base/core.c:3537 [inline]
 device_add+0xc1/0xbf0 drivers/base/core.c:3588
 usb_add_gadget+0x43e/0x780 drivers/usb/gadget/udc/core.c:1448
 usb_add_gadget_udc_release drivers/usb/gadget/udc/core.c:1504 [inline]
 usb_add_gadget_udc+0x11e/0x160 drivers/usb/gadget/udc/core.c:1551
 dummy_udc_probe+0x6ea/0x7f0 drivers/usb/gadget/udc/dummy_hcd.c:1102
 platform_probe+0x17a/0x200 drivers/base/platform.c:1404
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
 __driver_probe_device+0x193/0x280 drivers/base/dd.c:799
 device_driver_attach+0xdb/0x1f0 drivers/base/dd.c:1126
 bind_store+0x1dc/0x230 drivers/base/bus.c:267
 drv_attr_store+0x91/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0x141/0x160 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x316/0x510 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x762/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Freed by task 323:
 kasan_save_stack mm/kasan/common.c:49 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
 kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:249 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2445 [inline]
 slab_free mm/slub.c:4714 [inline]
 kfree+0x158/0x440 mm/slub.c:4875
 device_release+0xb6/0x1e0 drivers/base/core.c:2572
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1a7/0x2a0 lib/kobject.c:737
 put_device+0x23/0x40 drivers/base/core.c:3800
 klist_devices_put+0x3c/0x60 drivers/base/bus.c:817
 klist_put lib/klist.c:221 [inline]
 klist_del+0xf5/0x120 lib/klist.c:230
 bus_remove_device+0x33f/0x370 drivers/base/bus.c:572
 device_del+0x583/0xcf0 drivers/base/core.c:3881
 usb_del_gadget+0x18f/0x200 drivers/usb/gadget/udc/core.c:1577
 usb_del_gadget_udc+0x19/0x30 drivers/usb/gadget/udc/core.c:1593
 dummy_udc_remove+0x5c/0x70 drivers/usb/gadget/udc/dummy_hcd.c:1123
 platform_remove+0x7e/0xb0 drivers/base/platform.c:1424
 device_remove drivers/base/dd.c:567 [inline]
 __device_release_driver drivers/base/dd.c:1272 [inline]
 device_release_driver_internal+0x4ad/0x830 drivers/base/dd.c:1295
 device_driver_detach+0x3f/0x50 drivers/base/dd.c:1331
 unbind_store+0x1ab/0x1f0 drivers/base/bus.c:244
 drv_attr_store+0x91/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0x141/0x160 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x316/0x510 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x762/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The buggy address belongs to the object at ffff888105a6b600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 168 bytes inside of
 freed 256-byte region [ffff888105a6b600, ffff888105a6b700)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x105a6a
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4000000000000040(head|zone=1)
page_type: f5(slab)
raw: 4000000000000040 ffff888100041b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080100010 00000001f5000000 0000000000000000
head: 4000000000000040 ffff888100041b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000080100010 00000001f5000000 0000000000000000
head: 4000000000000001 ffffea0004169a81 ffffffffffffffff 0000000000000000
head: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 13, tgid 13 (kworker/u8:1), ts 2433510300, free_ts 0
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook+0x37d/0x3b0 mm/page_alloc.c:1863
 prep_new_page+0x2d/0x180 mm/page_alloc.c:1871
 get_page_from_freelist+0x4aea/0x4ba0 mm/page_alloc.c:3948
 __alloc_pages_noprof+0x35a/0x7e0 mm/page_alloc.c:5315
 alloc_slab_page+0x6b/0x1e0 mm/slub.c:-1
 allocate_slab+0x69/0x430 mm/slub.c:2687
 new_slab mm/slub.c:2741 [inline]
 ___slab_alloc+0x591/0x8c0 mm/slub.c:3934
 __slab_alloc mm/slub.c:4025 [inline]
 __slab_alloc_node mm/slub.c:4078 [inline]
 slab_alloc_node mm/slub.c:4239 [inline]
 __kmalloc_cache_noprof+0x2cd/0x470 mm/slub.c:4421
 kmalloc_noprof include/linux/slab.h:881 [inline]
 scsi_probe_and_add_lun+0x2b5/0x3e60 drivers/scsi/scsi_scan.c:1211
 __scsi_scan_target+0x1f1/0xc20 drivers/scsi/scsi_scan.c:1754
 scsi_scan_channel drivers/scsi/scsi_scan.c:1842 [inline]
 scsi_scan_host_selected+0x352/0x610 drivers/scsi/scsi_scan.c:1871
 do_scsi_scan_host drivers/scsi/scsi_scan.c:2010 [inline]
 do_scan_async+0x131/0x790 drivers/scsi/scsi_scan.c:2020
 async_run_entry_fn+0xaa/0x310 kernel/async.c:129
 process_one_work kernel/workqueue.c:3273 [inline]
 process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
 kthread+0x2c7/0x360 kernel/kthread.c:389
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888105a6b580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888105a6b600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888105a6b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888105a6b700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888105a6b780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 323 at lib/refcount.c:28 refcount_warn_saturate+0x119/0x1c0 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 323 Comm: syz-executor303 Tainted: G    B              syzkaller #0 1c659cfea3877f078df945e50c8eb7045fd035a9
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:refcount_warn_saturate+0x119/0x1c0 lib/refcount.c:28
Code: 05 01 48 c7 c7 80 ec 51 86 e8 43 79 55 fe 0f 0b eb da e8 0a a1 d8 fe c6 05 88 7a 36 05 01 48 c7 c7 e0 ec 51 86 e8 27 79 55 fe <0f> 0b eb be e8 ee a0 d8 fe c6 05 69 7a 36 05 01 48 c7 c7 20 ec 51
RSP: 0018:ffffc9000125fa48 EFLAGS: 00010246
RAX: ab0adcd64ef7b900 RBX: 0000000000000003 RCX: ffff8881057a1300
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc9000125fa58 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e9f34c R12: 0000000000000000
R13: ffff888104f88d34 R14: ffff888104f88d30 R15: ffff888104f88d30
FS:  000055557ed06480(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000100 CR3: 0000000104f66000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:400 [inline]
 __refcount_dec_and_test include/linux/refcount.h:432 [inline]
 refcount_dec_and_test include/linux/refcount.h:450 [inline]
 kref_put include/linux/kref.h:64 [inline]
 kobject_put+0x25a/0x2a0 lib/kobject.c:737
 put_device+0x23/0x40 drivers/base/core.c:3800
 usb_put_gadget include/linux/usb/gadget.h:512 [inline]
 usb_del_gadget_udc+0x25/0x30 drivers/usb/gadget/udc/core.c:1594
 dummy_udc_remove+0x5c/0x70 drivers/usb/gadget/udc/dummy_hcd.c:1123
 platform_remove+0x7e/0xb0 drivers/base/platform.c:1424
 device_remove drivers/base/dd.c:567 [inline]
 __device_release_driver drivers/base/dd.c:1272 [inline]
 device_release_driver_internal+0x4ad/0x830 drivers/base/dd.c:1295
 device_driver_detach+0x3f/0x50 drivers/base/dd.c:1331
 unbind_store+0x1ab/0x1f0 drivers/base/bus.c:244
 drv_attr_store+0x91/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0x141/0x160 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x316/0x510 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x762/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fc34475abf9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffebbb6f408 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffebbb6f440 RCX: 00007fc34475abf9
RDX: 000000000000000b RSI: 0000200000000400 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000000f4240 R09: 00000000000f4240
R10: 00000000000f4240 R11: 0000000000000246 R12: 00000000000f4240
R13: 0000000000000002 R14: 00007ffebbb6f42c R15: 00007ffebbb6f430
 </TASK>
---[ end trace 0000000000000000 ]---

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/04 20:10 android16-6.12 315636ba7cbf d4abbeac .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: slab-use-after-free Read in driver_deferred_probe_del
2026/07/24 19:07 android16-6.12 41c3d4eb44a7 dd737a83 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: slab-use-after-free Read in driver_deferred_probe_del
2026/08/05 08:05 android16-6.12 f068f96e8cc3 52aa2820 .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: slab-use-after-free Read in driver_deferred_probe_del
2026/07/24 20:24 android16-6.12 41c3d4eb44a7 dd737a83 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: slab-use-after-free Read in driver_deferred_probe_del
* Struck through repros no longer work on HEAD.