==================================================================
BUG: KASAN: use-after-free in v4l2_fh_init+0x279/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25
Read of size 8 at addr ffff8881c56308c8 by task v4l_id/437

CPU: 0 PID: 437 Comm: v4l_id Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xef/0x16e lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:382
 __kasan_report.cold+0x37/0x92 mm/kasan/report.c:511
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 v4l2_fh_init+0x279/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25
 v4l2_fh_open+0x88/0xc0 drivers/media/v4l2-core/v4l2-fh.c:63
 em28xx_v4l2_open+0x11a/0x570 drivers/media/usb/em28xx/em28xx-video.c:2163
 v4l2_open+0x20f/0x3d0 drivers/media/v4l2-core/v4l2-dev.c:423
 chrdev_open+0x219/0x5c0 fs/char_dev.c:414
 do_dentry_open+0x4ac/0x1160 fs/open.c:797
 do_open fs/namei.c:3229 [inline]
 path_openat+0x1a0b/0x2740 fs/namei.c:3346
 do_filp_open+0x192/0x260 fs/namei.c:3373
 do_sys_openat2+0x585/0x7d0 fs/open.c:1148
 do_sys_open+0xc3/0x140 fs/open.c:1164
 do_syscall_64+0xb6/0x5a0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x7f4b7120f840
Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24
RSP: 002b:00007ffc5b2f1638 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffc5b2f17a8 RCX: 00007f4b7120f840
RDX: 00007f4b711fbea0 RSI: 0000000000000000 RDI: 00007ffc5b2f1f25
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 000056242adba8d0
R13: 00007ffc5b2f17a0 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0007158c00 refcount:0 mapcount:-128 mapping:0000000041a24cc8 index:0x0
flags: 0x200000000000000()
raw: 0200000000000000 ffffea000726c108 ffffea0007159a08 0000000000000000
raw: 0000000000000000 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881c5630780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c5630800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881c5630880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8881c5630900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881c5630980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================