possible deadlock in btrfs_create_qgroup

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=106e2d97880000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=612ed3b940119a3f68de
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+612ed3...@syzkaller.appspotmail.com

audit: type=1800 audit(1670310233.941:1518): pid=18336 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="loop5" ino=263 res=0
======================================================
WARNING: possible circular locking dependency detected
4.19.211-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/18336 is trying to acquire lock:
000000007a863766 (&fs_info->qgroup_ioctl_lock){+.+.}, at: btrfs_create_qgroup+0x5a/0x270 fs/btrfs/qgroup.c:1380

but task is already holding lock:
00000000214ed586 (sb_internal#4){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline]
00000000214ed586 (sb_internal#4){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_internal#4){.+.+}:
sb_start_intwrite include/linux/fs.h:1626 [inline]
start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528
btrfs_quota_enable+0x169/0x10b0 fs/btrfs/qgroup.c:905
btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:5233 [inline]
btrfs_ioctl+0x622c/0x76d0 fs/btrfs/ioctl.c:6021
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (&fs_info->qgroup_ioctl_lock){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:937 [inline]
__mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078
btrfs_create_qgroup+0x5a/0x270 fs/btrfs/qgroup.c:1380
btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:5335 [inline]
btrfs_ioctl+0xcce/0x76d0 fs/btrfs/ioctl.c:6025
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(sb_internal#4);
lock(&fs_info->qgroup_ioctl_lock);
lock(sb_internal#4);
lock(&fs_info->qgroup_ioctl_lock);

*** DEADLOCK ***

2 locks held by syz-executor.5/18336:
#0: 000000008f60b514 (sb_writers#35){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
#0: 000000008f60b514 (sb_writers#35){.+.+}, at: mnt_want_write_file+0x63/0x1d0 fs/namespace.c:418
#1: 00000000214ed586 (sb_internal#4){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline]
#1: 00000000214ed586 (sb_internal#4){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528

stack backtrace:
CPU: 1 PID: 18336 Comm: syz-executor.5 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
check_prev_add kernel/locking/lockdep.c:1866 [inline]
check_prevs_add kernel/locking/lockdep.c:1979 [inline]
validate_chain kernel/locking/lockdep.c:2420 [inline]
__lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
__mutex_lock_common kernel/locking/mutex.c:937 [inline]
__mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078
btrfs_create_qgroup+0x5a/0x270 fs/btrfs/qgroup.c:1380
btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:5335 [inline]
btrfs_ioctl+0xcce/0x76d0 fs/btrfs/ioctl.c:6025
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f7096f3e0d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f70954b0168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f709705df80 RCX: 00007f7096f3e0d9
RDX: 00000000200000c0 RSI: 000000004010942a RDI: 0000000000000004
RBP: 00007f7096f99ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc2d29d54f R14: 00007f70954b0300 R15: 0000000000022000
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
audit: type=1800 audit(1670310235.391:1519): pid=18445 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="loop5" ino=263 res=0
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
audit: type=1800 audit(1670310236.031:1520): pid=18560 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="loop5" ino=263 res=0
batadv0: This device is already a HSR slave.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
audit: type=1800 audit(1670310236.301:1521): pid=18618 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="loop5" ino=263 res=0
nla_parse: 4 callbacks suppressed
netlink: 40 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 40 bytes leftover after parsing attributes in process `syz-executor.1'.
audit: type=1800 audit(1670310236.551:1522): pid=18678 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14717 res=0
audit: type=1800 audit(1670310236.551:1523): pid=18678 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14717 res=0
batadv0: This device is already a HSR slave.
netlink: 40 bytes leftover after parsing attributes in process `syz-executor.1'.
audit: type=1800 audit(1670310236.551:1524): pid=18678 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14717 res=0
audit: type=1800 audit(1670310236.551:1525): pid=18678 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14717 res=0
audit: type=1800 audit(1670310236.561:1526): pid=18678 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14717 res=0
audit: type=1800 audit(1670310236.561:1527): pid=18678 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14717 res=0
BTRFS info (device loop5): using free space tree
audit: type=1800 audit(1670310236.561:1528): pid=18678 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14717 res=0
BTRFS info (device loop5): has skinny extents
netlink: 40 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 40 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 40 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 20 bytes leftover after parsing attributes in process `syz-executor.1'.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
batadv0: This device is already a HSR slave.
netlink: 20 bytes leftover after parsing attributes in process `syz-executor.1'.
netlink: 20 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 40 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
batadv0: This device is already a HSR slave.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
kauditd_printk_skb: 61 callbacks suppressed
audit: type=1800 audit(1670310241.162:1590): pid=19011 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="loop5" ino=263 res=0
audit: type=1800 audit(1670310241.202:1591): pid=19144 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="loop5" ino=263 res=0
batadv0: This device is already a HSR slave.
nla_parse: 11 callbacks suppressed
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
audit: type=1800 audit(1670310241.992:1592): pid=19163 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="loop5" ino=263 res=0
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
audit: type=1800 audit(1670310242.282:1593): pid=19295 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=13955 res=0
batadv0: This device is already a HSR slave.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
audit: type=1800 audit(1670310242.772:1594): pid=19375 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="bus" dev="sda1" ino=14732 res=0
batadv0: This device is already a HSR slave.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
BTRFS info (device loop5): using free space tree
BTRFS info (device loop5): has skinny extents
batadv0: This device is already a HSR slave.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
batadv0: This device is already a HSR slave.


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y

console output: https://syzkaller.appspot.com/x/log.txt?x=141f8bdb880000

kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=612ed3b940119a3f68de
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=109a296f880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11300a6f880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/fe49ba0e3362/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+612ed3...@syzkaller.appspotmail.com

BTRFS: device fsid 24c7a497-3402-47dd-bef8-82358f5f30e0 devid 1 transid 8 /dev/loop0
BTRFS info (device loop0): using free space tree
BTRFS info (device loop0): has skinny extents

======================================================
WARNING: possible circular locking dependency detected
4.19.211-syzkaller #0 Not tainted
------------------------------------------------------

syz-executor221/8122 is trying to acquire lock:
00000000266b3a34 (&fs_info->qgroup_ioctl_lock){+.+.}, at: btrfs_create_qgroup+0x5a/0x270 fs/btrfs/qgroup.c:1380

but task is already holding lock:

000000005b756e52 (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline]
000000005b756e52 (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_internal#2){.+.+}:

lock(sb_internal#2);
lock(&fs_info->qgroup_ioctl_lock);
lock(sb_internal#2);

lock(&fs_info->qgroup_ioctl_lock);

*** DEADLOCK ***

2 locks held by syz-executor221/8122:
#0: 000000005aca81aa (sb_writers#11){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
#0: 000000005aca81aa (sb_writers#11){.+.+}, at: mnt_want_write_file+0x63/0x1d0 fs/namespace.c:418
#1: 000000005b756e52 (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline]
#1: 000000005b756e52 (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528

stack backtrace:
CPU: 0 PID: 8122 Comm: syz-executor221 Not tainted 4.19.211-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
check_prev_add kernel/locking/lockdep.c:1866 [inline]
check_prevs_add kernel/locking/lockdep.c:1979 [inline]
validate_chain kernel/locking/lockdep.c:2420 [inline]
__lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
__mutex_lock_common kernel/locking/mutex.c:937 [inline]
__mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078
btrfs_create_qgroup+0x5a/0x270 fs/btrfs/qgroup.c:1380
btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:5335 [inline]
btrfs_ioctl+0xcce/0x76d0 fs/btrfs/ioctl.c:6025
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
__do_sys_ioctl fs/ioctl.c:712 [inline]
__se_sys_ioctl fs/ioctl.c:710 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

RIP: 0033:0x7f606a4fd7f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 7