================================================================== BUG: KASAN: use-after-free in v4l2_open+0x32d/0x340 drivers/media/v4l2-core/v4l2-dev.c:432 Read of size 4 at addr ffff8880728287e8 by task v4l_id/15032 CPU: 0 PID: 15032 Comm: v4l_id Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x188/0x24e 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 v4l2_open+0x32d/0x340 drivers/media/v4l2-core/v4l2-dev.c:432 chrdev_open+0x585/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3634 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3791 do_filp_open+0x1ee/0x420 fs/namei.c:3818 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 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 RIP: 0033:0x7fd20bca7407 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:00007ffdf9796070 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fd20c3fb880 RCX: 00007fd20bca7407 RDX: 0000000000000000 RSI: 00007ffdf9796f1b RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffdf97962c0 R14: 00007fd20c55a000 R15: 000055cd292444d8 Allocated by task 5155: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] em28xx_v4l2_init+0xf5/0x2d90 drivers/media/usb/em28xx/em28xx-video.c:2538 em28xx_init_extension+0x118/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1116 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 process_scheduled_works kernel/workqueue.c:2355 [inline] worker_thread+0xdd1/0x12a0 kernel/workqueue.c:2444 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 5155: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3700 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x15f7/0x2d90 drivers/media/usb/em28xx/em28xx-video.c:2907 em28xx_init_extension+0x118/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1116 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 process_scheduled_works kernel/workqueue.c:2355 [inline] worker_thread+0xdd1/0x12a0 kernel/workqueue.c:2444 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff888072828000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2024 bytes inside of 8192-byte region [ffff888072828000, ffff88807282a000) The buggy address belongs to the physical page: page:ffffea0001ca0a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x72828 head:ffffea0001ca0a00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888017442280 raw: 0000000000000000 0000000080020002 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4019, tgid 4019 (start-stop-daem), ts 51940354888, free_ts 51893648372 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560 prep_new_page mm/page_alloc.c:2567 [inline] get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658 alloc_slab_page+0x5d/0x180 mm/slub.c:1799 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2d0 mm/slub.c:1997 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] tomoyo_print_bprm security/tomoyo/audit.c:26 [inline] tomoyo_init_log+0x10a3/0x1f90 security/tomoyo/audit.c:264 tomoyo_supervisor+0x361/0x11b0 security/tomoyo/common.c:2088 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline] tomoyo_env_perm+0x14e/0x1f0 security/tomoyo/environ.c:63 tomoyo_environ security/tomoyo/domain.c:672 [inline] tomoyo_find_next_domain+0x12dd/0x1a30 security/tomoyo/domain.c:882 tomoyo_bprm_check_security+0x100/0x150 security/tomoyo/tomoyo.c:101 security_bprm_check+0x5e/0x90 security/security.c:870 search_binary_handler fs/exec.c:1752 [inline] exec_binprm fs/exec.c:1805 [inline] bprm_execve+0xa5d/0x17e0 fs/exec.c:1874 do_execveat_common+0x501/0x6b0 fs/exec.c:1979 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1487 [inline] free_pcp_prepare mm/page_alloc.c:1537 [inline] free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509 free_slab mm/slub.c:2036 [inline] discard_slab mm/slub.c:2042 [inline] __unfreeze_partials+0x188/0x1e0 mm/slub.c:2591 put_cpu_partial+0x17c/0x250 mm/slub.c:2667 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:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] __kmem_cache_alloc_node+0x19d/0x270 mm/slub.c:3398 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc+0xa3/0x240 mm/slab_common.c:949 kmalloc include/linux/slab.h:568 [inline] tomoyo_add_entry security/tomoyo/common.c:2022 [inline] tomoyo_supervisor+0xc66/0x11b0 security/tomoyo/common.c:2094 tomoyo_audit_path_log security/tomoyo/file.c:168 [inline] tomoyo_path_permission+0x262/0x3a0 security/tomoyo/file.c:587 tomoyo_path_perm+0x46a/0x610 security/tomoyo/file.c:838 security_inode_getattr+0xcf/0x120 security/security.c:1362 vfs_getattr+0x26/0x3a0 fs/stat.c:158 vfs_fstat fs/stat.c:183 [inline] __do_sys_newfstat fs/stat.c:447 [inline] __se_sys_newfstat fs/stat.c:444 [inline] __x64_sys_newfstat+0x13d/0x220 fs/stat.c:444 Memory state around the buggy address: ffff888072828680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888072828700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888072828780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888072828800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888072828880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================