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BUG: KASAN: use-after-free in v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline]
BUG: KASAN: use-after-free in v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63
Read of size 8 at addr ffff88805aa94900 by task v4l_id/5686

CPU: 1 PID: 5686 Comm: v4l_id Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline]
 v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63
 em28xx_v4l2_open+0x152/0x990 drivers/media/usb/em28xx/em28xx-video.c:2163
 v4l2_open+0x20b/0x360 drivers/media/v4l2-core/v4l2-dev.c:427
 chrdev_open+0x597/0x670 fs/char_dev.c:414
 do_dentry_open+0x7ff/0xf80 fs/open.c:826
 do_open fs/namei.c:3616 [inline]
 path_openat+0x2682/0x2f30 fs/namei.c:3750
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
 do_sys_openat2+0x142/0x4a0 fs/open.c:1255
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_openat fs/open.c:1287 [inline]
 __se_sys_openat fs/open.c:1282 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1282
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f18ca3a3407
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:00007ffd69d7d8f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f18ca2b5880 RCX: 00007f18ca3a3407
RDX: 0000000000000000 RSI: 00007ffd69d7ef1b RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffd69d7db40 R14: 00007f18cab31000 R15: 0000561f9b01c4d8
 </TASK>

The buggy address belongs to the page:
page:ffffea00016aa500 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x2 pfn:0x5aa94
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001665808 ffff88813fffb910 0000000000000000
raw: 0000000000000002 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x102800(GFP_NOWAIT|__GFP_NOWARN|__GFP_HARDWALL), pid 5689, ts 132241561462, free_ts 132241566397
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487
 stack_depot_save+0x342/0x440 lib/stackdepot.c:302
 kasan_save_stack+0x4b/0x60 mm/kasan/common.c:40
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x182/0x930 kernel/rcu/tree.c:3091
 __dentry_kill+0x4ef/0x650 fs/dcache.c:600
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xd8/0x1a0 fs/dcache.c:893
 ovl_lookup_positive_unlocked fs/overlayfs/namei.c:215 [inline]
 ovl_lookup_single+0x486/0x850 fs/overlayfs/namei.c:230
 ovl_lookup_layer+0x379/0x440 fs/overlayfs/namei.c:314
 ovl_lookup+0x6af/0x16c0 fs/overlayfs/namei.c:914
 lookup_open fs/namei.c:3448 [inline]
 open_last_lookups fs/namei.c:3540 [inline]
 path_openat+0x1003/0x2f30 fs/namei.c:3747
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
 do_sys_openat2+0x142/0x4a0 fs/open.c:1255
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_creat fs/open.c:1347 [inline]
 __se_sys_creat fs/open.c:1341 [inline]
 __x64_sys_creat+0x8c/0xb0 fs/open.c:1341
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x94/0x280 mm/page_alloc.c:3396
 stack_depot_save+0x418/0x440 lib/stackdepot.c:335
 kasan_save_stack+0x4b/0x60 mm/kasan/common.c:40
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x182/0x930 kernel/rcu/tree.c:3091
 __dentry_kill+0x4ef/0x650 fs/dcache.c:600
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xd8/0x1a0 fs/dcache.c:893
 ovl_lookup_positive_unlocked fs/overlayfs/namei.c:215 [inline]
 ovl_lookup_single+0x486/0x850 fs/overlayfs/namei.c:230
 ovl_lookup_layer+0x379/0x440 fs/overlayfs/namei.c:314
 ovl_lookup+0x6af/0x16c0 fs/overlayfs/namei.c:914
 lookup_open fs/namei.c:3448 [inline]
 open_last_lookups fs/namei.c:3540 [inline]
 path_openat+0x1003/0x2f30 fs/namei.c:3747
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
 do_sys_openat2+0x142/0x4a0 fs/open.c:1255
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_creat fs/open.c:1347 [inline]
 __se_sys_creat fs/open.c:1341 [inline]
 __x64_sys_creat+0x8c/0xb0 fs/open.c:1341

Memory state around the buggy address:
 ffff88805aa94800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805aa94880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805aa94900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88805aa94980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805aa94a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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