KASAN: use-after-free Write in detach_if_pending (2)

Status: premoderation: reported on 2025/06/06 23:25
Reported-by: syzbot+7130f0814f3661965e91@syzkaller.appspotmail.com
First crash: 461d, last: 9h47m
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-54 KASAN: use-after-free Write in detach_if_pending 22 syz, C 1618 473d 1309d 0/2 upstream: reported C repro on 2023/02/10 18:19
upstream KASAN: use-after-free Write in detach_if_pending net 22 syz, C 4169 3246d 3241d 3/29 fixed on 2017/11/28 03:36
android-6-1 KASAN: use-after-free Write in detach_if_pending 22 5 570d 692d 0/2 auto-obsoleted due to no activity on 2025/05/18 23:57
upstream general protection fault in detach_if_pending (2) net 2 1 1643d 1643d 0/29 auto-closed as invalid on 2022/06/11 02:46
linux-4.14 general protection fault in detach_if_pending (2) 2 1 1953d 1953d 0/1 auto-closed as invalid on 2021/09/04 11:36
upstream general protection fault in detach_if_pending (3) fs kvm 2 5 808d 808d 0/29 closed as invalid on 2024/08/16 18:25
upstream KASAN: invalid-access Write in detach_if_pending wireguard -1 2 2033d 2035d 0/29 auto-closed as invalid on 2021/05/17 08:51
upstream KASAN: slab-use-after-free Write in detach_if_pending batman wireguard 22 2 1225d 1234d 0/29 auto-obsoleted due to no activity on 2023/11/08 05:10
android-54 BUG: Bad page map (4) -1 18 484d 584d 0/2 auto-obsoleted due to no activity on 2025/08/04 13:44

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:884 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:886 [inline]
BUG: KASAN: use-after-free in detach_if_pending+0x158/0x300 kernel/time/timer.c:905
Write of size 8 at addr ffff88811c90c9f8 by task syz-executor/289

CPU: 1 PID: 289 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report_generic.c:356
 __hlist_del include/linux/list.h:884 [inline]
 detach_timer kernel/time/timer.c:886 [inline]
 detach_if_pending+0x158/0x300 kernel/time/timer.c:905
 del_timer+0x75/0xb0 kernel/time/timer.c:1330
 try_to_grab_pending+0xc9/0x580 kernel/workqueue.c:1285
 mod_delayed_work_on+0x44/0xe0 kernel/workqueue.c:1745
 mod_delayed_work include/linux/workqueue.h:540 [inline]
 wb_queue_work+0x2aa/0x3b0 fs/fs-writeback.c:171
 bdi_split_work_to_wbs+0x4e1/0xa50 fs/fs-writeback.c:1000
 __writeback_inodes_sb_nr+0x216/0x280 fs/fs-writeback.c:2675
 writeback_inodes_sb_nr fs/fs-writeback.c:2693 [inline]
 writeback_inodes_sb+0x74/0x80 fs/fs-writeback.c:2708
 sync_filesystem+0xa2/0x240 fs/sync.c:54
 generic_shutdown_super+0x6e/0x480 fs/super.c:478
 kill_block_super+0x7f/0xf0 fs/super.c:1475
 deactivate_locked_super+0xb5/0x120 fs/super.c:336
 deactivate_super+0xaf/0xe0 fs/super.c:367
 cleanup_mnt+0x45e/0x4e0 fs/namespace.c:1192
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1199
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5c3679f397
Code: a2 c7 05 5c 43 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc9054e1b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5c3683448b RCX: 00007f5c3679f397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc9054e270
RBP: 00007ffc9054e270 R08: 00007ffc9054f270 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc9054f300
R13: 00007f5c3683448b R14: 0000000000011d30 R15: 00007ffc9054f340
 </TASK>

Allocated by task 1369:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc+0xb4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 hci_alloc_dev_priv+0x27/0x1bd0 net/bluetooth/hci_core.c:2433
 hci_alloc_dev include/net/bluetooth/hci_core.h:1505 [inline]
 hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:669 [inline]
 hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:754 [inline]
 hci_uart_tty_ioctl+0x3c4/0xa70 drivers/bluetooth/hci_ldisc.c:809
 tty_ioctl+0x8ef/0xc60 drivers/tty/tty_io.c:2785
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 1369:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 hci_release_dev+0x12a3/0x13b0 net/bluetooth/hci_core.c:2761
 bt_host_release+0x82/0x90 net/bluetooth/hci_sysfs.c:85
 device_release+0xa4/0x1d0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:681 [inline]
 kobject_release lib/kobject.c:712 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x19d/0x280 lib/kobject.c:729
 put_device+0x1f/0x30 drivers/base/core.c:3806
 hci_dev_put include/net/bluetooth/hci_core.h:1465 [inline]
 hci_dev_cmd+0x279/0x740 net/bluetooth/hci_core.c:795
 hci_sock_ioctl+0x41e/0x7f0 net/bluetooth/hci_sock.c:1096
 sock_do_ioctl+0x114/0x330 net/socket.c:1192
 sock_ioctl+0x475/0x700 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
 insert_work+0x51/0x300 kernel/workqueue.c:1368
 __queue_work+0x9d0/0xd50 kernel/workqueue.c:1527
 queue_work_on+0xde/0x150 kernel/workqueue.c:1555
 queue_work include/linux/workqueue.h:510 [inline]
 hci_cmd_sync_run net/bluetooth/hci_sync.c:140 [inline]
 __hci_cmd_sync_sk+0xaa8/0xd80 net/bluetooth/hci_sync.c:162
 __hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:253 [inline]
 __hci_cmd_sync_status net/bluetooth/hci_sync.c:277 [inline]
 hci_cmd_sync_status+0x53/0x120 net/bluetooth/hci_sync.c:288
 hci_dev_cmd+0x357/0x740 net/bluetooth/hci_core.c:749
 hci_sock_ioctl+0x41e/0x7f0 net/bluetooth/hci_sock.c:1096
 sock_do_ioctl+0x114/0x330 net/socket.c:1192
 sock_ioctl+0x475/0x700 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
 insert_work+0x51/0x300 kernel/workqueue.c:1368
 __queue_work+0x9d0/0xd50 kernel/workqueue.c:1527
 queue_work_on+0xde/0x150 kernel/workqueue.c:1555
 queue_work include/linux/workqueue.h:510 [inline]
 hci_cmd_timeout+0x191/0x200 net/bluetooth/hci_core.c:1468
 process_one_work+0x717/0xc30 kernel/workqueue.c:2302
 worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff88811c90c000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2552 bytes inside of
 8192-byte region [ffff88811c90c000, ffff88811c90e000)

The buggy address belongs to the physical page:
page:ffffea0004724200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11c908
head:ffffea0004724200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100043500
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 535, tgid 534 (syz.2.57), ts 35769138667, free_ts 35761818202
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2673
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2680
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4587
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5931
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3e0 mm/slub.c:2020
 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
 kmalloc_trace+0x29/0xb0 mm/slab_common.c:1028
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 fat_fill_super+0x144/0x4940 fs/fat/inode.c:1625
 vfat_fill_super+0x2f/0x40 fs/fat/namei_vfat.c:1205
 mount_bdev+0x29b/0x3d0 fs/super.c:1448
 vfat_mount+0x34/0x40 fs/fat/namei_vfat.c:1212
 legacy_get_tree+0xfe/0x1a0 fs/fs_context.c:632
 vfs_get_tree+0x9a/0x270 fs/super.c:1578
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1581 [inline]
 free_pcp_prepare mm/page_alloc.c:1655 [inline]
 free_unref_page_prepare+0x81b/0x820 mm/page_alloc.c:3622
 free_unref_page+0x93/0x530 mm/page_alloc.c:3720
 free_the_page mm/page_alloc.c:863 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:6021
 __free_slab+0xc7/0x1a0 mm/slub.c:2044
 free_slab mm/slub.c:2059 [inline]
 discard_slab mm/slub.c:2065 [inline]
 __unfreeze_partials+0x15a/0x190 mm/slub.c:2614
 put_cpu_partial+0xa9/0x100 mm/slub.c:2690
 __slab_free+0x1c4/0x280 mm/slub.c:3589
 do_slab_free mm/slub.c:3666 [inline]
 ___cache_free+0xbf/0xd0 mm/slub.c:3722
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:311
 kasan_slab_alloc include/linux/kasan.h:202 [inline]
 slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768
 slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc mm/slub.c:3392 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3399 [inline]
 kmem_cache_alloc+0x166/0x320 mm/slub.c:3408
 prepare_creds+0x2f/0x610 kernel/cred.c:263
 access_override_creds fs/open.c:377 [inline]
 do_faccessat+0xe8/0x9b0 fs/open.c:441
 __do_sys_faccessat2 fs/open.c:501 [inline]
 __se_sys_faccessat2 fs/open.c:498 [inline]
 __x64_sys_faccessat2+0x9a/0xb0 fs/open.c:498

Memory state around the buggy address:
 ffff88811c90c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811c90c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811c90c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff88811c90ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811c90ca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (24):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/11 10:03 android14-6.1 b16e29e4979f 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/08/22 19:51 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/06/19 23:25 android14-6.1 9f35ca3ff66c 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/06/03 03:04 android14-6.1 80aded6fbb9d 3c0d2131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/05/17 23:24 android14-6.1 75487b40c943 de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/05/04 06:10 android14-6.1 1e4e23ff0f90 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/04/21 22:12 android14-6.1 69e1e941dbe1 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/04/21 18:07 android14-6.1 69e1e941dbe1 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/04/10 05:46 android14-6.1 b1e92db6a41f 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/03/17 08:45 android14-6.1 299d5eca2e4a c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/02/24 10:46 android14-6.1 34c1a8e17200 96b1aa46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/02/20 06:35 android14-6.1 edbe3e111301 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/02/19 22:50 android14-6.1 edbe3e111301 c8d8c52d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/02/15 19:17 android14-6.1 edbe3e111301 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/02/15 12:47 android14-6.1 edbe3e111301 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/02/11 18:10 android14-6.1 edbe3e111301 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/01/26 10:22 android14-6.1 5b3c238664a9 a4c52dd6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/01/23 18:23 android14-6.1 d1c598f45d0f e2b1b6e6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/01/20 15:18 android14-6.1 1c6403722ffe 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2026/01/19 03:14 android14-6.1 37a76cbe8f87 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2025/11/03 08:23 android14-6.1 3e2aa22eb7df 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2025/10/14 23:06 android14-6.1 c65cfeb3d9b5 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2025/07/20 19:03 android14-6.1 145c7fad733f 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
2025/06/06 23:24 android14-6.1 7af56ffc913d 9fa58bba .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: use-after-free Write in detach_if_pending
* Struck through repros no longer work on HEAD.