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BUG: KASAN: use-after-free in btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245
Read of size 8 at addr ffff88809c5b06a8 by task syz-executor.5/31176

CPU: 1 PID: 31176 Comm: syz-executor.5 Not tainted 5.9.0-rc6-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+0x1d6/0x29e lib/dump_stack.c:118
 print_address_description+0x66/0x620 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245
 device_list_add+0x1a88/0x1d60 fs/btrfs/volumes.c:943
 btrfs_scan_one_device+0x196/0x490 fs/btrfs/volumes.c:1359
 btrfs_mount_root+0x48f/0xb60 fs/btrfs/super.c:1634
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x88/0x270 fs/super.c:1547
 fc_mount fs/namespace.c:978 [inline]
 vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008
 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x88/0x270 fs/super.c:1547
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x179d/0x29e0 fs/namespace.c:3192
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount+0x126/0x180 fs/namespace.c:3390
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x460bca
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 dd 87 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 ba 87 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f29ea778a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f29ea778b20 RCX: 0000000000460bca
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f29ea778ae0
RBP: 00007f29ea778ae0 R08: 00007f29ea778b20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 000000002001a800

Allocated by task 31108:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
 kmalloc_node include/linux/slab.h:577 [inline]
 kvmalloc_node+0x81/0x110 mm/util.c:574
 kvmalloc include/linux/mm.h:757 [inline]
 kvzalloc include/linux/mm.h:765 [inline]
 btrfs_mount_root+0xd0/0xb60 fs/btrfs/super.c:1613
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x88/0x270 fs/super.c:1547
 fc_mount fs/namespace.c:978 [inline]
 vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008
 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x88/0x270 fs/super.c:1547
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x179d/0x29e0 fs/namespace.c:3192
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount+0x126/0x180 fs/namespace.c:3390
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 31108:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track+0x3d/0x70 mm/kasan/common.c:56
 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422
 __cache_free mm/slab.c:3422 [inline]
 kfree+0x113/0x200 mm/slab.c:3760
 deactivate_locked_super+0xa7/0xf0 fs/super.c:335
 btrfs_mount_root+0x72b/0xb60 fs/btrfs/super.c:1678
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x88/0x270 fs/super.c:1547
 fc_mount fs/namespace.c:978 [inline]
 vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008
 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732
 legacy_get_tree+0xea/0x180 fs/fs_context.c:592
 vfs_get_tree+0x88/0x270 fs/super.c:1547
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x179d/0x29e0 fs/namespace.c:3192
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount+0x126/0x180 fs/namespace.c:3390
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809c5b0000
 which belongs to the cache kmalloc-16k of size 16384
The buggy address is located 1704 bytes inside of
 16384-byte region [ffff88809c5b0000, ffff88809c5b4000)
The buggy address belongs to the page:
page:0000000001ba636f refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9c5b0
head:0000000001ba636f order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea000114ec08 ffffea00024ac408 ffff8880aa440b00
raw: 0000000000000000 ffff88809c5b0000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809c5b0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809c5b0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809c5b0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff88809c5b0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809c5b0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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