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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 ffff888063580900 by task v4l_id/10889

CPU: 0 PID: 10889 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+0x188/0x250 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+0x5c5/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x7ff/0xf80 fs/open.c:826
 do_open fs/namei.c:3616 [inline]
 path_openat+0x26f5/0x2fa0 fs/namei.c:3750
 do_filp_open+0x1e2/0x410 fs/namei.c:3777
 do_sys_openat2+0x150/0x4b0 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: 0033:0x7f3f4c8d3407
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:00007ffc4af81dd0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f3f4c7e5880 RCX: 00007f3f4c8d3407
RDX: 0000000000000000 RSI: 00007ffc4af82f1b RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffc4af82020 R14: 00007f3f4d061000 R15: 000056039ec494d8
 </TASK>

The buggy address belongs to the page:
page:ffffea00018d6000 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x63580
flags: 0xfff00000010000(head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x140cc0(GFP_USER|__GFP_COMP), pid 4245, ts 272825141121, free_ts 272468716418
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5487
 kmalloc_order+0x40/0x150 mm/slab_common.c:986
 kmalloc_order_trace+0x14/0xf0 mm/slab_common.c:1002
 hid_alloc_buffers drivers/hid/usbhid/hid-core.c:857 [inline]
 usbhid_start+0x8d5/0x24a0 drivers/hid/usbhid/hid-core.c:1089
 hid_hw_start+0x5b/0x100 drivers/hid/hid-core.c:2090
 hid_device_probe+0x271/0x360 drivers/hid/hid-core.c:2323
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x284/0xc80 drivers/base/dd.c:595
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
 __device_attach_driver+0x2b0/0x500 drivers/base/dd.c:907
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a8/0x480 drivers/base/dd.c:979
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3412
 hid_add_device+0x389/0x530 drivers/hid/hid-core.c:2475
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+0x8f/0x2a0 mm/page_alloc.c:3396
 free_nonslab_page+0xe2/0x150 mm/slub.c:3540
 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2128 [inline]
 kref_put include/linux/kref.h:65 [inline]
 em28xx_v4l2_init+0x1649/0x2e50 drivers/media/usb/em28xx/em28xx-video.c:2911
 em28xx_init_extension+0x118/0x1b0 drivers/media/usb/em28xx/em28xx-core.c:1126
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff888063580800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888063580880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888063580900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                   ^
 ffff888063580980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888063580a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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