================================================================== BUG: KASAN: slab-use-after-free in v4l2_open+0x351/0x490 drivers/media/v4l2-core/v4l2-dev.c:444 Read of size 4 at addr ffff88807cfdc860 by task v4l_id/6296 CPU: 1 UID: 0 PID: 6296 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 v4l2_open+0x351/0x490 drivers/media/v4l2-core/v4l2-dev.c:444 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6ab/0x14d0 fs/open.c:947 vfs_open+0x82/0x3f0 fs/open.c:1052 do_open fs/namei.c:4700 [inline] path_openat+0x2873/0x4280 fs/namei.c:4859 do_file_open+0x20e/0x430 fs/namei.c:4888 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1385 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbfce1df407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffde119fd50 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fbfce153880 RCX: 00007fbfce1df407 RDX: 0000000000000000 RSI: 00007ffde11a0f1c RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffde119ffa0 R14: 00007fbfce438000 R15: 000055d122b814d8 Allocated by task 5938: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x2e5/0x6c0 mm/slub.c:5515 _kmalloc_noprof include/linux/slab.h:969 [inline] _kzalloc_noprof include/linux/slab.h:1290 [inline] em28xx_v4l2_init.cold+0x94/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:2709 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 5938: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2705 [inline] slab_free mm/slub.c:6405 [inline] kfree+0x22b/0x6c0 mm/slub.c:6720 kref_put.isra.0+0x53/0x75 include/linux/kref.h:65 em28xx_v4l2_init.cold+0x280/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:3080 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88807cfdc000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2144 bytes inside of freed 8192-byte region [ffff88807cfdc000, ffff88807cfde000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7cfd8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813fe25280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe25280 dead000000000100 dead000000000122 head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5611, tgid 5611 (sh), ts 61325193677, free_ts 61175520587 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3294 [inline] allocate_slab mm/slub.c:3408 [inline] new_slab+0xa2/0x650 mm/slub.c:3454 refill_objects+0xe3/0x410 mm/slub.c:7338 refill_sheaf mm/slub.c:2832 [inline] __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4703 alloc_from_pcs mm/slub.c:4801 [inline] slab_alloc_node mm/slub.c:4933 [inline] __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5511 _kmalloc_noprof include/linux/slab.h:969 [inline] _kzalloc_noprof include/linux/slab.h:1290 [inline] tomoyo_print_bprm security/tomoyo/audit.c:26 [inline] tomoyo_init_log+0xc4f/0x20c0 security/tomoyo/audit.c:262 tomoyo_supervisor+0x506/0x1340 security/tomoyo/common.c:2232 tomoyo_audit_env_log security/tomoyo/environ.c:37 [inline] tomoyo_env_perm+0x191/0x200 security/tomoyo/environ.c:64 tomoyo_environ security/tomoyo/domain.c:673 [inline] tomoyo_find_next_domain+0x13d7/0x2010 security/tomoyo/domain.c:889 tomoyo_bprm_check_security security/tomoyo/tomoyo.c:102 [inline] tomoyo_bprm_check_security+0x12d/0x1d0 security/tomoyo/tomoyo.c:92 security_bprm_check+0x87/0x1e0 security/security.c:820 search_binary_handler fs/exec.c:1684 [inline] exec_binprm fs/exec.c:1726 [inline] bprm_execve fs/exec.c:1778 [inline] bprm_execve+0x84b/0x1730 fs/exec.c:1754 do_execveat_common.isra.0+0x4a5/0x580 fs/exec.c:1876 __do_sys_execve fs/exec.c:1949 [inline] __se_sys_execve fs/exec.c:1943 [inline] __x64_sys_execve+0x93/0xd0 fs/exec.c:1943 page last free pid 5608 tgid 5608 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4612 [inline] slab_alloc_node mm/slub.c:4945 [inline] __do_kmalloc_node mm/slub.c:5361 [inline] __kmalloc_node_track_caller_noprof+0x2cd/0x830 mm/slub.c:5497 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637 __alloc_skb+0x185/0x710 net/core/skbuff.c:715 alloc_skb include/linux/skbuff.h:1384 [inline] alloc_skb_with_frags+0xdd/0x760 net/core/skbuff.c:6769 sock_alloc_send_pskb+0x801/0x980 net/core/sock.c:3010 unix_stream_sendmsg+0x3f4/0x1310 net/unix/af_unix.c:2436 sock_sendmsg_nosec net/socket.c:775 [inline] __sock_sendmsg net/socket.c:790 [inline] sock_write_iter+0x53a/0x5b0 net/socket.c:1241 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x1f8/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88807cfdc700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807cfdc780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807cfdc800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807cfdc880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807cfdc900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================