====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/9804 is trying to acquire lock: 000000002fae3538 (&fs_info->qgroup_ioctl_lock){+.+.}, at: btrfs_remove_qgroup+0xae/0x770 fs/btrfs/qgroup.c:1415 but task is already holding lock: 0000000038468b9b (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline] 0000000038468b9b (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_remove_qgroup+0xae/0x770 fs/btrfs/qgroup.c:1415 btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:5337 [inline] btrfs_ioctl+0x661c/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: BTRFS error (device loop3): fail to start transaction for status update: -28 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.3/9804: #0: 00000000f8bdd0f7 (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline] #0: 00000000f8bdd0f7 (sb_writers#14){.+.+}, at: mnt_want_write_file+0x63/0x1d0 fs/namespace.c:418 #1: 0000000038468b9b (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline] #1: 0000000038468b9b (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528 stack backtrace: CPU: 1 PID: 9804 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_remove_qgroup+0xae/0x770 fs/btrfs/qgroup.c:1415 btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:5337 [inline] btrfs_ioctl+0x661c/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: 0033:0x7f85ec75a0a9 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:00007f85e38ab168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f85ec87a050 RCX: 00007f85ec75a0a9 RDX: 00000000200011c0 RSI: 000000004010942a RDI: 0000000000000004 RBP: 00007f85ec7b5ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd2e54faff R14: 00007f85e38ab300 R15: 0000000000022000 BTRFS info (device loop4): using free space tree BTRFS info (device loop4): has skinny extents BTRFS error (device loop4): fail to start transaction for status update: -28 BTRFS warning (device ): duplicate device /dev/loop3 devid 1 generation 8 scanned by syz-executor.3 (9828) BTRFS info (device loop3): using free space tree BTRFS info (device loop3): has skinny extents BTRFS warning (device ): duplicate device /dev/loop4 devid 1 generation 8 scanned by syz-executor.4 (9872) BTRFS warning (device ): duplicate device /dev/loop4 devid 1 generation 8 scanned by systemd-udevd (9909) netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. BTRFS error (device loop3): fail to start transaction for status update: -28 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. BTRFS info (device loop4): using free space tree netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. BTRFS info (device loop4): has skinny extents netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. BTRFS error (device loop4): 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 ubi0: attaching mtd0 ubi0: scanning is finished ubi0: empty MTD device detected ubi0: attached mtd0 (name "mtdram test device", size 0 MiB) ubi0: PEB size: 4096 bytes (4 KiB), LEB size: 3968 bytes ubi0: min./max. I/O unit sizes: 1/64, sub-page size 1 ubi0: VID header offset: 64 (aligned 64), data offset: 128 ubi0: good PEBs: 32, bad PEBs: 0, corrupted PEBs: 0 ubi0: user volume: 0, internal volumes: 1, max. volumes count: 23 ubi0: max/mean erase counter: 0/0, WL threshold: 4096, image sequence number: 4190749851 ubi0: available PEBs: 28, total reserved PEBs: 4, PEBs reserved for bad PEB handling: 0 ubi0: background thread "ubi_bgt0d" started, PID 10066 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0