syzbot

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BUG: KASAN: slab-use-after-free in v4l2_open+0x395/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:444
Read of size 4 at addr ffff88801b168810 by task v4l_id/6152

CPU: 1 UID: 0 PID: 6152 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 v4l2_open+0x395/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:444
 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
 do_dentry_open+0x785/0x14e0 fs/open.c:949
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4693 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4852
 do_file_open+0x23e/0x4a0 fs/namei.c:4881
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa818fde407
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:00007ffdbeaca3e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa818f52880 RCX: 00007fa818fde407
RDX: 0000000000000000 RSI: 00007ffdbeacaf1c RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffdbeaca630 R14: 00007fa819237000 R15: 0000562990aec4d8
 </TASK>

Allocated by task 809:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5412
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 em28xx_v4l2_init+0x10b/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2538
 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117
 process_one_work+0x9ab/0x1780 kernel/workqueue.c:3289
 process_scheduled_works kernel/workqueue.c:3380 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 809:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6242 [inline]
 kfree+0x1c5/0x650 mm/slub.c:6557
 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline]
 kref_put include/linux/kref.h:65 [inline]
 em28xx_v4l2_init+0x1683/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2907
 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117
 process_one_work+0x9ab/0x1780 kernel/workqueue.c:3289
 process_scheduled_works kernel/workqueue.c:3380 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 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 ffff88801b168000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2064 bytes inside of
 freed 8192-byte region [ffff88801b168000, ffff88801b16a000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1b168
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 ffff88801b042280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042280 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 5499, tgid 5499 (S40network), ts 54008512816, free_ts 53918866034
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1857
 prep_new_page mm/page_alloc.c:1865 [inline]
 get_page_from_freelist+0x2418/0x24b0 mm/page_alloc.c:3924
 __alloc_frozen_pages_noprof+0x233/0x3d0 mm/page_alloc.c:5211
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7247
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5407
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_print_bprm security/tomoyo/audit.c:26 [inline]
 tomoyo_init_log+0x112e/0x1fb0 security/tomoyo/audit.c:264
 tomoyo_supervisor+0x353/0x1570 security/tomoyo/common.c:2232
 tomoyo_audit_env_log security/tomoyo/environ.c:37 [inline]
 tomoyo_env_perm+0x151/0x1f0 security/tomoyo/environ.c:64
 tomoyo_environ security/tomoyo/domain.c:673 [inline]
 tomoyo_find_next_domain+0x15cb/0x1aa0 security/tomoyo/domain.c:889
 tomoyo_bprm_check_security+0x11b/0x180 security/tomoyo/tomoyo.c:102
 security_bprm_check+0x85/0x240 security/security.c:794
 search_binary_handler fs/exec.c:1654 [inline]
 exec_binprm fs/exec.c:1696 [inline]
 bprm_execve+0x8a2/0x1470 fs/exec.c:1748
 do_execveat_common+0x50d/0x690 fs/exec.c:1846
 __do_sys_execve fs/exec.c:1930 [inline]
 __se_sys_execve fs/exec.c:1924 [inline]
 __x64_sys_execve+0x97/0xc0 fs/exec.c:1924
page last free pid 5497 tgid 5497 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1401 [inline]
 __free_frozen_pages+0xbf0/0xd00 mm/page_alloc.c:2942
 __slab_free+0x274/0x2c0 mm/slub.c:5605
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 __kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5407
 kmalloc_noprof include/linux/slab.h:950 [inline]
 tomoyo_print_header security/tomoyo/audit.c:156 [inline]
 tomoyo_init_log+0x195/0x1fb0 security/tomoyo/audit.c:255
 tomoyo_supervisor+0x353/0x1570 security/tomoyo/common.c:2232
 tomoyo_audit_path_log security/tomoyo/file.c:169 [inline]
 tomoyo_path_permission+0x25a/0x380 security/tomoyo/file.c:592
 tomoyo_check_open_permission+0x2b2/0x470 security/tomoyo/file.c:782
 security_file_open+0xa9/0x240 security/security.c:2661
 do_dentry_open+0x384/0x14e0 fs/open.c:926
 vfs_open+0x3b/0x340 fs/open.c:1081
 do_open fs/namei.c:4693 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4852
 do_file_open+0x23e/0x4a0 fs/namei.c:4881
 do_sys_openat2+0x113/0x200 fs/open.c:1366

Memory state around the buggy address:
 ffff88801b168700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801b168780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801b168800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88801b168880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801b168900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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