syzbot

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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 ffff88804f8e4860 by task v4l_id/6243

CPU: 1 UID: 0 PID: 6243 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __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:1079
 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:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x12d/0x210 fs/open.c:1412
 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: 0033:0x7f6c30fdf407
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:00007ffc2c6fce30 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6c30f53880 RCX: 00007f6c30fdf407
RDX: 0000000000000000 RSI: 00007ffc2c6fdf1c RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffc2c6fd080 R14: 00007f6c31238000 R15: 00005609e50cb4d8
 </TASK>

Allocated by task 991:
 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
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 em28xx_v4l2_init.cold+0x94/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:2707
 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:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 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 991:
 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:2700 [inline]
 slab_free mm/slub.c:6310 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6625
 kref_put.isra.0+0x53/0x75 include/linux/kref.h:65
 em28xx_v4l2_init.cold+0x280/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:3078
 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:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 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 ffff88804f8e4000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2144 bytes inside of
 freed 8192-byte region [ffff88804f8e4000, ffff88804f8e6000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4f8e0
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 ffff88813fe38280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe38280 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 5274, tgid 5274 (dhcpcd), ts 26028979644, free_ts 26028617461
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x812/0x3d20 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x27c/0x2b60 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab mm/slub.c:3404 [inline]
 new_slab+0xa2/0x670 mm/slub.c:3447
 refill_objects+0xe3/0x430 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x375/0x660 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __kmalloc_cache_noprof+0x48d/0x6e0 mm/slub.c:5446
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [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 5274 tgid 5274 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938
 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:4610 [inline]
 slab_alloc_node mm/slub.c:4939 [inline]
 __kmalloc_cache_noprof+0x243/0x6e0 mm/slub.c:5446
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [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
 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:
 ffff88804f8e4700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804f8e4780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88804f8e4800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88804f8e4880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804f8e4900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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