==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919
Read of size 8 at addr ffff88811f9124f0 by task kworker/u4:4/570

CPU: 1 PID: 570 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: kkcmd kcm_tx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe3/0x16b lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 __lock_sock+0x148/0x250 net/core/sock.c:2916
 lock_sock_nested+0x81/0xe0 net/core/sock.c:3493
 lock_sock include/net/sock.h:1756 [inline]
 kcm_tx_work+0x28/0x140 net/kcm/kcmsock.c:731
 process_one_work+0x799/0xea0 kernel/workqueue.c:2292
 worker_thread+0x8cc/0xfb0 kernel/workqueue.c:2439
 kthread+0x259/0x2d0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Allocated by task 2847:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6b/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3383
 sk_prot_alloc+0x51/0x1b0 net/core/sock.c:2044
 sk_alloc+0x30/0x2d0 net/core/sock.c:2103
 kcm_clone net/kcm/kcmsock.c:1640 [inline]
 kcm_ioctl+0x28f/0xe40 net/kcm/kcmsock.c:1685
 sock_do_ioctl+0xcd/0x260 net/socket.c:1204
 sock_ioctl+0x41d/0x540 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xa6/0xf0 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 2848:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free+0xf7/0x290 mm/slub.c:3709
 sk_prot_free net/core/sock.c:2084 [inline]
 __sk_destruct+0x353/0x4b0 net/core/sock.c:2172
 kcm_release+0x3ad/0x550 net/kcm/kcmsock.c:1860
 __sock_release net/socket.c:654 [inline]
 sock_close+0xcb/0x220 net/socket.c:1400
 __fput+0x1a9/0x700 fs/file_table.c:320
 task_work_run+0x142/0x1e0 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xda/0xf0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xa9/0x120 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 insert_work+0x4f/0x330 kernel/workqueue.c:1361
 __queue_work+0x93d/0xc40 kernel/workqueue.c:1520
 queue_work_on+0xcb/0x160 kernel/workqueue.c:1548
 queue_work include/linux/workqueue.h:512 [inline]
 kcm_unattach+0x858/0xe30 net/kcm/kcmsock.c:1549
 kcm_unattach_ioctl net/kcm/kcmsock.c:1606 [inline]
 kcm_ioctl+0x69d/0xe40 net/kcm/kcmsock.c:1673
 sock_do_ioctl+0xcd/0x260 net/socket.c:1204
 sock_ioctl+0x41d/0x540 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xa6/0xf0 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 insert_work+0x4f/0x330 kernel/workqueue.c:1361
 __queue_work+0x93d/0xc40 kernel/workqueue.c:1520
 queue_work_on+0xcb/0x160 kernel/workqueue.c:1548
 kcm_attach net/kcm/kcmsock.c:1429 [inline]
 kcm_attach_ioctl net/kcm/kcmsock.c:1457 [inline]
 kcm_ioctl+0xc20/0xe40 net/kcm/kcmsock.c:1663
 sock_do_ioctl+0xcd/0x260 net/socket.c:1204
 sock_ioctl+0x41d/0x540 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xa6/0xf0 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88811f912440
 which belongs to the cache KCM of size 1720
The buggy address is located 176 bytes inside of
 1720-byte region [ffff88811f912440, ffff88811f912af8)

The buggy address belongs to the physical page:
page:ffffea00047e4400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f910
head:ffffea00047e4400 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88810466fa01
flags: 0x200000000010200(slab|head|node=0|zone=2)
raw: 0200000000010200 0000000000000000 dead000000000122 ffff888107f4d780
raw: 0000000000000000 0000000080110011 00000001ffffffff ffff88810466fa01
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 2817, tgid 2814 (syz.2.17), ts 101115598020, free_ts 101063542490
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x24d6/0x2650 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
 alloc_slab_page+0x5d/0x160 mm/slub.c:1799
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x87/0x2c0 mm/slub.c:1997
 ___slab_alloc+0xbc6/0x1230 mm/slub.c:3154
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x1b7/0x2f0 mm/slub.c:3383
 sk_prot_alloc+0x51/0x1b0 net/core/sock.c:2044
 sk_alloc+0x30/0x2d0 net/core/sock.c:2103
 kcm_clone net/kcm/kcmsock.c:1640 [inline]
 kcm_ioctl+0x28f/0xe40 net/kcm/kcmsock.c:1685
 sock_do_ioctl+0xcd/0x260 net/socket.c:1204
 sock_ioctl+0x41d/0x540 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xa6/0xf0 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x822/0x860 mm/page_alloc.c:3384
 free_unref_page+0x2e/0x3c0 mm/page_alloc.c:3479
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3383
 getname_flags+0xa0/0x430 fs/namei.c:139
 user_path_at_empty+0x1b/0x50 fs/namei.c:2904
 do_readlinkat+0xbe/0x380 fs/stat.c:468
 __do_sys_readlink fs/stat.c:501 [inline]
 __se_sys_readlink fs/stat.c:498 [inline]
 __x64_sys_readlink+0x76/0x80 fs/stat.c:498
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88811f912380: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
 ffff88811f912400: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff88811f912480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff88811f912500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811f912580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================