BTRFS: device fsid 24c7a497-3402-47dd-bef8-82358f5f30e0 devid 1 transid 8 /dev/loop3 BTRFS info (device loop3): using free space tree BTRFS info (device loop3): has skinny extents ====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/10947 is trying to acquire lock: 000000004ef267c0 (&fs_info->qgroup_ioctl_lock){+.+.}, at: btrfs_limit_qgroup+0x63/0x7b0 fs/btrfs/qgroup.c:1467 but task is already holding lock: 000000006e25795a (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline] 000000006e25795a (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){.+.+}: 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_limit_qgroup+0x63/0x7b0 fs/btrfs/qgroup.c:1467 btrfs_ioctl_qgroup_limit fs/btrfs/ioctl.c:5386 [inline] btrfs_ioctl+0x3c0c/0x76d0 fs/btrfs/ioctl.c:6027 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#2); lock(&fs_info->qgroup_ioctl_lock); lock(sb_internal#2); lock(&fs_info->qgroup_ioctl_lock); *** DEADLOCK *** 2 locks held by syz-executor.3/10947: #0: 000000001e26322a (sb_writers#19){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 000000001e26322a (sb_writers#19){.+.+}, at: mnt_want_write_file+0x63/0x1d0 fs/namespace.c:418 #1: 000000006e25795a (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline] #1: 000000006e25795a (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528 stack backtrace: CPU: 0 PID: 10947 Comm: syz-executor.3 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_limit_qgroup+0x63/0x7b0 fs/btrfs/qgroup.c:1467 btrfs_ioctl_qgroup_limit fs/btrfs/ioctl.c:5386 [inline] btrfs_ioctl+0x3c0c/0x76d0 fs/btrfs/ioctl.c:6027 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: 0033:0x7fe2d4d3e0d9 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:00007fe2d32b0168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe2d4e5df80 RCX: 00007fe2d4d3e0d9 RDX: 0000000020001140 RSI: 000000008030942b RDI: 0000000000000004 RBP: 00007fe2d4d99ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc0415161f R14: 00007fe2d32b0300 R15: 0000000000022000 BTRFS error (device loop3): fail to start transaction for status update: -28 BTRFS info (device loop3): using free space tree BTRFS info (device loop3): has skinny extents BTRFS error (device loop3): fail to start transaction for status update: -28 BTRFS info (device loop3): using free space tree BTRFS info (device loop3): has skinny extents BTRFS error (device loop3): fail to start transaction for status update: -28 x_tables: duplicate underflow at hook 1 BTRFS info (device loop3): using free space tree BTRFS info (device loop3): has skinny extents BTRFS error (device loop3): fail to start transaction for status update: -28 audit: type=1326 audit(1669768848.613:5): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=11362 comm="syz-executor.5" exe="/root/syz-executor.5" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7fdbfb7120d9 code=0x0 audit: type=1326 audit(1669768849.383:6): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=11401 comm="syz-executor.4" exe="/root/syz-executor.4" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7f97d1d340d9 code=0x0 L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.