Hello,
syzbot found the following issue on:
HEAD commit: c79648372d02 Linux 5.15.189
git tree: linux-5.15.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=1629bf22580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=f3b1215b3cf4119f
dashboard link:
https://syzkaller.appspot.com/bug?extid=f905ba9e11def6007fca
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:
https://syzkaller.appspot.com/x/repro.syz?x=1129bf22580000
C reproducer:
https://syzkaller.appspot.com/x/repro.c?x=14cdeb82580000
Downloadable assets:
disk image:
https://storage.googleapis.com/syzbot-assets/8f7ef907dd63/disk-c7964837.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/c9fa50894c6f/vmlinux-c7964837.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/78f74ec5a263/bzImage-c7964837.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+f905ba...@syzkaller.appspotmail.com
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0xf7/0x7c60 kernel/locking/lockdep.c:4882
Read of size 8 at addr ffff88807d9f24e0 by task kworker/u4:1/144
CPU: 0 PID: 144 Comm: kworker/u4:1 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: kkcmd kcm_tx_work
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
print_address_description+0x60/0x2d0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0xdf/0x130 mm/kasan/report.c:451
__lock_acquire+0xf7/0x7c60 kernel/locking/lockdep.c:4882
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:368 [inline]
__lock_sock+0x152/0x2a0 net/core/sock.c:2702
lock_sock_nested+0x9d/0x100 net/core/sock.c:3256
lock_sock include/net/sock.h:1694 [inline]
kcm_tx_work+0x2d/0x180 net/kcm/kcmsock.c:730
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Allocated by task 4328:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x9c/0xd0 mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3220 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0x100/0x290 mm/slub.c:3233
sk_prot_alloc+0x57/0x210 net/core/sock.c:1858
sk_alloc+0x2f/0x310 net/core/sock.c:1917
kcm_clone net/kcm/kcmsock.c:1641 [inline]
kcm_ioctl+0x211/0xff0 net/kcm/kcmsock.c:1686
sock_do_ioctl+0xd3/0x2f0 net/socket.c:1140
sock_ioctl+0x4ed/0x6e0 net/socket.c:1257
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Freed by task 4329:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1705 [inline]
slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kmem_cache_free+0x8f/0x210 mm/slub.c:3515
sk_prot_free net/core/sock.c:1898 [inline]
__sk_destruct+0x54b/0x820 net/core/sock.c:1986
kcm_release+0x51a/0x5b0 net/kcm/kcmsock.c:1861
__sock_release net/socket.c:649 [inline]
sock_close+0xd5/0x240 net/socket.c:1336
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Last potentially related work creation:
kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
insert_work+0x54/0x3d0 kernel/workqueue.c:1366
__queue_work+0x9c5/0xd50 kernel/workqueue.c:1532
queue_work_on+0x11d/0x1d0 kernel/workqueue.c:1559
queue_work include/linux/workqueue.h:512 [inline]
kcm_unattach+0x85e/0xe80 net/kcm/kcmsock.c:1550
kcm_unattach_ioctl net/kcm/kcmsock.c:1607 [inline]
kcm_ioctl+0x78d/0xff0 net/kcm/kcmsock.c:1674
sock_do_ioctl+0xd3/0x2f0 net/socket.c:1140
sock_ioctl+0x4ed/0x6e0 net/socket.c:1257
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Second to last potentially related work creation:
kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
insert_work+0x54/0x3d0 kernel/workqueue.c:1366
__queue_work+0x9c5/0xd50 kernel/workqueue.c:1532
queue_work_on+0x11d/0x1d0 kernel/workqueue.c:1559
kcm_attach net/kcm/kcmsock.c:1430 [inline]
kcm_attach_ioctl net/kcm/kcmsock.c:1458 [inline]
kcm_ioctl+0xe4b/0xff0 net/kcm/kcmsock.c:1664
sock_do_ioctl+0xd3/0x2f0 net/socket.c:1140
sock_ioctl+0x4ed/0x6e0 net/socket.c:1257
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
The buggy address belongs to the object at ffff88807d9f2440
which belongs to the cache KCM of size 1728
The buggy address is located 160 bytes inside of
1728-byte region [ffff88807d9f2440, ffff88807d9f2b00)
The buggy address belongs to the page:
page:ffffea0001f67c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7d9f0
head:ffffea0001f67c00 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88807c8a8501
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88814c9f33c0
raw: 0000000000000000 0000000080110011 00000001ffffffff ffff88807c8a8501
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 4312, ts 81548300042, free_ts 81472519570
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
__alloc_pages+0x1e1/0x470 mm/page_alloc.c:5474
alloc_slab_page mm/slub.c:1775 [inline]
allocate_slab mm/slub.c:1912 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1975
___slab_alloc+0x81e/0xdf0 mm/slub.c:3008
__slab_alloc mm/slub.c:3095 [inline]
slab_alloc_node mm/slub.c:3186 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0x195/0x290 mm/slub.c:3233
sk_prot_alloc+0x57/0x210 net/core/sock.c:1858
sk_alloc+0x2f/0x310 net/core/sock.c:1917
kcm_clone net/kcm/kcmsock.c:1641 [inline]
kcm_ioctl+0x211/0xff0 net/kcm/kcmsock.c:1686
sock_do_ioctl+0xd3/0x2f0 net/socket.c:1140
sock_ioctl+0x4ed/0x6e0 net/socket.c:1257
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
free_unref_page+0x94/0x280 mm/page_alloc.c:3396
free_slab mm/slub.c:2015 [inline]
discard_slab mm/slub.c:2021 [inline]
__unfreeze_partials+0x1a5/0x200 mm/slub.c:2507
put_cpu_partial+0x12d/0x190 mm/slub.c:2587
qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3220 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0x100/0x290 mm/slub.c:3233
getname_flags+0xb5/0x500 fs/namei.c:138
do_sys_openat2+0xcf/0x4a0 fs/open.c:1247
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
Memory state around the buggy address:
ffff88807d9f2380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88807d9f2400: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff88807d9f2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807d9f2500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807d9f2580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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