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BUG: KASAN: use-after-free in btrfs_printk+0x312/0x380 fs/btrfs/super.c:218
Read of size 8 at addr ffff8880893d4690 by task systemd-udevd/13824

CPU: 1 PID: 13824 Comm: systemd-udevd Not tainted 5.4.0-rc8-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+0xa0/0xea lib/dump_stack.c:118
 print_address_description.constprop.4.cold.6+0x9/0x376 mm/kasan/report.c:374
 __kasan_report.cold.7+0x7d/0xa2 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:634
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 btrfs_printk+0x312/0x380 fs/btrfs/super.c:218
 device_list_add+0xe41/0x1600 fs/btrfs/volumes.c:865
 btrfs_scan_one_device+0x2c8/0x880 fs/btrfs/volumes.c:1281
 btrfs_control_ioctl+0xbe/0x220 fs/btrfs/super.c:2192
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x196/0x1150 fs/ioctl.c:696
 ksys_ioctl+0x62/0x90 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:718
 do_syscall_64+0x93/0x4e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7efe92be3017
Code: 00 00 00 48 8b 05 81 7e 2b 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 7e 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffebc01bb58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007efe92be3017
RDX: 00007ffebc01bb70 RSI: 0000000090009427 RDI: 000000000000000f
RBP: 00007ffebc01bb70 R08: 0000000000000000 R09: 0000000000000150
R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000000f
R13: 0000000000000000 R14: 0000562fdfa5c810 R15: 0000562fdfa4a060

The buggy address belongs to the page:
page:ffffea000224f500 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0
raw: 00fff00000000000 ffffea0002aec508 ffffea00022ab908 0000000000000000
raw: 0000000000000000 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880893d4580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880893d4600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880893d4680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff8880893d4700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880893d4780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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