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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 ffff888116494900 by task v4l_id/26071

CPU: 0 PID: 26071 Comm: v4l_id Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 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+0x11c/0x570 drivers/media/usb/em28xx/em28xx-video.c:2163
 v4l2_open+0x21c/0x3f0 drivers/media/v4l2-core/v4l2-dev.c:427
 chrdev_open+0x266/0x770 fs/char_dev.c:414
 do_dentry_open+0x4b4/0x1100 fs/open.c:824
 do_open fs/namei.c:3426 [inline]
 path_openat+0x1c9e/0x2940 fs/namei.c:3559
 do_filp_open+0x1aa/0x400 fs/namei.c:3586
 do_sys_openat2+0x16d/0x4d0 fs/open.c:1214
 do_sys_open fs/open.c:1230 [inline]
 __do_sys_openat fs/open.c:1246 [inline]
 __se_sys_openat fs/open.c:1241 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f3dc7fdd697
Code: 25 00 00 41 00 3d 00 00 41 00 74 37 64 8b 04 25 18 00 00 00 85 c0 75 5b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 85 00 00 00 48 83 c4 68 5d 41 5c c3 0f 1f
RSP: 002b:00007fffa915c590 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055e3c9050c40 RCX: 00007f3dc7fdd697
RDX: 0000000000000000 RSI: 00007fffa915df21 RDI: 00000000ffffff9c
RBP: 00007fffa915df21 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to the page:
page:ffffea0004592500 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x116494
flags: 0x200000000000000(node=0|zone=2)
raw: 0200000000000000 ffffea0004ade108 ffff8881f683da70 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 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 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 4098, ts 3244309283553, free_ts 3244529712307
 prep_new_page mm/page_alloc.c:2418 [inline]
 get_page_from_freelist+0x122d/0x2940 mm/page_alloc.c:4149
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369
 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2190
 kmalloc_order+0x34/0xf0 mm/slab_common.c:949
 kmalloc_order_trace+0x14/0x120 mm/slab_common.c:965
 kmalloc_large include/linux/slab.h:511 [inline]
 kmalloc include/linux/slab.h:575 [inline]
 kzalloc include/linux/slab.h:716 [inline]
 em28xx_v4l2_init drivers/media/usb/em28xx/em28xx-video.c:2542 [inline]
 em28xx_v4l2_init.cold+0x67/0x326f drivers/media/usb/em28xx/em28xx-video.c:2520
 em28xx_init_extension+0x12f/0x1f0 drivers/media/usb/em28xx/em28xx-core.c:1126
 request_module_async+0x5d/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3415
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 process_scheduled_works kernel/workqueue.c:2370 [inline]
 worker_thread+0x7e2/0x1110 kernel/workqueue.c:2459
 kthread+0x40b/0x500 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1338 [inline]
 free_pcp_prepare+0x361/0x760 mm/page_alloc.c:1389
 free_unref_page_prepare mm/page_alloc.c:3309 [inline]
 free_unref_page+0x19/0x580 mm/page_alloc.c:3388
 kref_put.isra.0+0x6f/0xa0 include/linux/kref.h:65
 em28xx_v4l2_init drivers/media/usb/em28xx/em28xx-video.c:2911 [inline]
 em28xx_v4l2_init.cold+0x238/0x326f drivers/media/usb/em28xx/em28xx-video.c:2520
 em28xx_init_extension+0x12f/0x1f0 drivers/media/usb/em28xx/em28xx-core.c:1126
 request_module_async+0x5d/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3415
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 process_scheduled_works kernel/workqueue.c:2370 [inline]
 worker_thread+0x7e2/0x1110 kernel/workqueue.c:2459
 kthread+0x40b/0x500 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff888116494800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888116494880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888116494900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888116494980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888116494a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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