================================================================== BUG: KASAN: use-after-free in __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919 Read of size 8 at addr ffff88807870df70 by task kworker/u4:3/46 CPU: 1 PID: 46 Comm: kworker/u4:3 Not tainted 6.1.147-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: kkcmd kcm_tx_work Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x200 mm/kasan/report.c:418 kasan_report+0x10b/0x140 mm/kasan/report.c:522 __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 lock_sock_nested+0x44/0x100 net/core/sock.c:3488 lock_sock include/net/sock.h:1756 [inline] kcm_tx_work+0x2d/0x180 net/kcm/kcmsock.c:731 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 4749: 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:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3422 sk_prot_alloc+0x57/0x210 net/core/sock.c:2044 sk_alloc+0x36/0x340 net/core/sock.c:2103 kcm_clone net/kcm/kcmsock.c:1640 [inline] kcm_ioctl+0x211/0xff0 net/kcm/kcmsock.c:1685 sock_do_ioctl+0xd3/0x2f0 net/socket.c:1204 sock_ioctl+0x4ed/0x6e0 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 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 4750: 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:1724 [inline] slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] kmem_cache_free+0xf7/0x290 mm/slub.c:3683 sk_prot_free net/core/sock.c:2084 [inline] __sk_destruct+0x48d/0x630 net/core/sock.c:2172 kcm_release+0x520/0x5b0 net/kcm/kcmsock.c:1860 __sock_release net/socket.c:654 [inline] sock_close+0xd5/0x240 net/socket.c:1400 __fput+0x22c/0x920 fs/file_table.c:320 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 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+0x54/0x3c0 kernel/workqueue.c:1361 __queue_work+0xba3/0xfb0 kernel/workqueue.c:1520 queue_work_on+0x11d/0x1d0 kernel/workqueue.c:1548 queue_work include/linux/workqueue.h:512 [inline] kcm_unattach+0x861/0xe80 net/kcm/kcmsock.c:1549 kcm_unattach_ioctl net/kcm/kcmsock.c:1606 [inline] kcm_ioctl+0x78d/0xff0 net/kcm/kcmsock.c:1673 sock_do_ioctl+0xd3/0x2f0 net/socket.c:1204 sock_ioctl+0x4ed/0x6e0 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 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+0x54/0x3c0 kernel/workqueue.c:1361 __queue_work+0xba3/0xfb0 kernel/workqueue.c:1520 queue_work_on+0x11d/0x1d0 kernel/workqueue.c:1548 kcm_attach net/kcm/kcmsock.c:1429 [inline] kcm_attach_ioctl net/kcm/kcmsock.c:1457 [inline] kcm_ioctl+0xe4b/0xff0 net/kcm/kcmsock.c:1663 sock_do_ioctl+0xd3/0x2f0 net/socket.c:1204 sock_ioctl+0x4ed/0x6e0 net/socket.c:1321 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 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 ffff88807870de40 which belongs to the cache KCM of size 1720 The buggy address is located 304 bytes inside of 1720-byte region [ffff88807870de40, ffff88807870e4f8) The buggy address belongs to the physical page: page:ffffea0001e1c200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78708 head:ffffea0001e1c200 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff88801df44501 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88802f12a500 raw: 0000000000000000 0000000080110011 00000001ffffffff ffff88801df44501 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 4704, tgid 4703 (syz.0.87), ts 158934984142, free_ts 158931967784 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+0x1a26/0x1ac0 mm/page_alloc.c:4328 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614 alloc_slab_page+0x5d/0x160 mm/slub.c:1794 allocate_slab mm/slub.c:1939 [inline] new_slab+0x87/0x2c0 mm/slub.c:1992 ___slab_alloc+0xbc6/0x1220 mm/slub.c:3180 __slab_alloc mm/slub.c:3279 [inline] slab_alloc_node mm/slub.c:3364 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x1b7/0x2f0 mm/slub.c:3422 sk_prot_alloc+0x57/0x210 net/core/sock.c:2044 sk_alloc+0x36/0x340 net/core/sock.c:2103 kcm_create+0xfc/0x570 net/kcm/kcmsock.c:1930 __sock_create+0x4a2/0x940 net/socket.c:1550 sock_create net/socket.c:1606 [inline] __sys_socket_create net/socket.c:1643 [inline] __sys_socket+0xc4/0x190 net/socket.c:1671 __do_sys_socket net/socket.c:1684 [inline] __se_sys_socket net/socket.c:1682 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1682 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+0x8b4/0x9a0 mm/page_alloc.c:3384 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3479 free_slab mm/slub.c:2031 [inline] discard_slab mm/slub.c:2037 [inline] __unfreeze_partials+0x1a5/0x200 mm/slub.c:2586 put_cpu_partial+0x17c/0x250 mm/slub.c:2662 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:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc_lru+0x11a/0x2e0 mm/slub.c:3429 alloc_inode_sb include/linux/fs.h:3245 [inline] shmem_alloc_inode+0x24/0x40 mm/shmem.c:3898 alloc_inode fs/inode.c:261 [inline] new_inode_pseudo+0x5f/0x1c0 fs/inode.c:1063 new_inode+0x25/0x1c0 fs/inode.c:1091 shmem_get_inode+0x347/0xbf0 mm/shmem.c:2354 shmem_symlink+0x97/0x670 mm/shmem.c:3150 vfs_symlink+0x247/0x3d0 fs/namei.c:4471 do_symlinkat+0x1ae/0x3f0 fs/namei.c:4500 Memory state around the buggy address: ffff88807870de00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff88807870de80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807870df00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807870df80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807870e000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================