gfs2: fsid=syz:syz.0: first mount done, others may mount ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.60/4671 is trying to acquire lock: ffff0000d9220ae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xbc/0x648 fs/gfs2/quota.c:682 but task is already holding lock: ffff0000e1ae2780 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x1f4/0x13f4 fs/gfs2/bmap.c:685 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ip->i_rw_mutex){++++}-{3:3}: down_read+0x64/0x300 kernel/locking/rwsem.c:1520 __gfs2_iomap_get+0x114/0x1044 fs/gfs2/bmap.c:862 gfs2_iomap_get+0xd4/0x144 fs/gfs2/bmap.c:1413 bh_get+0x1e4/0x604 fs/gfs2/quota.c:385 qd_fish fs/gfs2/quota.c:485 [inline] gfs2_quota_sync+0x230/0x500 fs/gfs2/quota.c:1320 gfs2_sync_fs+0x4c/0xc4 fs/gfs2/super.c:664 sync_filesystem+0xe8/0x218 fs/sync.c:56 generic_shutdown_super+0x70/0x324 fs/super.c:474 kill_block_super+0x70/0xdc fs/super.c:1470 gfs2_kill_sb+0xc0/0xd4 fs/gfs2/ops_fstype.c:-1 deactivate_locked_super+0xac/0x120 fs/super.c:332 deactivate_super+0xe4/0x104 fs/super.c:363 cleanup_mnt+0x390/0x418 fs/namespace.c:1191 __cleanup_mnt+0x20/0x30 fs/namespace.c:1198 task_work_run+0x1ec/0x278 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x1fa0/0x2aa4 arch/arm64/kernel/signal.c:1151 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 -> #0 (&sdp->sd_quota_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 do_qc+0xbc/0x648 fs/gfs2/quota.c:682 gfs2_quota_change+0x238/0x718 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x13b8/0x1ab8 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x388/0x13f4 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x134/0x1c4 fs/gfs2/bmap.c:1426 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xbd0/0x1758 fs/gfs2/file.c:1331 gfs2_fallocate+0x34c/0x494 fs/gfs2/file.c:1395 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290 file_ioctl fs/ioctl.c:-1 [inline] do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849 __do_sys_ioctl fs/ioctl.c:868 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ip->i_rw_mutex); lock(&sdp->sd_quota_mutex); lock(&ip->i_rw_mutex); lock(&sdp->sd_quota_mutex); *** DEADLOCK *** 5 locks held by syz.4.60/4671: #0: ffff0000dcc52460 (sb_writers#20){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3015 [inline] #0: ffff0000dcc52460 (sb_writers#20){.+.+}-{0:0}, at: vfs_fallocate+0x434/0x5f4 fs/open.c:322 #1: ffff0000e1ae22e8 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff0000e1ae22e8 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: gfs2_fallocate+0x190/0x494 fs/gfs2/file.c:1374 #2: ffff0000dcc52650 (sb_internal#5){.+.+}-{0:0}, at: gfs2_trans_begin+0xa8/0x114 fs/gfs2/trans.c:118 #3: ffff0000d9221058 (&sdp->sd_log_flush_lock){++++}-{3:3}, at: __gfs2_trans_begin+0x500/0x870 fs/gfs2/trans.c:87 #4: ffff0000e1ae2780 (&ip->i_rw_mutex){++++}-{3:3}, at: __gfs2_iomap_alloc+0x1f4/0x13f4 fs/gfs2/bmap.c:685 stack backtrace: CPU: 1 PID: 4671 Comm: syz.4.60 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048 check_noncircular+0x264/0x2f8 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2880/0x6800 kernel/locking/lockdep.c:5049 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 do_qc+0xbc/0x648 fs/gfs2/quota.c:682 gfs2_quota_change+0x238/0x718 fs/gfs2/quota.c:1295 gfs2_alloc_blocks+0x13b8/0x1ab8 fs/gfs2/rgrp.c:2494 __gfs2_iomap_alloc+0x388/0x13f4 fs/gfs2/bmap.c:711 gfs2_iomap_alloc+0x134/0x1c4 fs/gfs2/bmap.c:1426 fallocate_chunk fs/gfs2/file.c:1192 [inline] __gfs2_fallocate+0xbd0/0x1758 fs/gfs2/file.c:1331 gfs2_fallocate+0x34c/0x494 fs/gfs2/file.c:1395 vfs_fallocate+0x4a4/0x5f4 fs/open.c:323 ioctl_preallocate+0x20c/0x2b4 fs/ioctl.c:290 file_ioctl fs/ioctl.c:-1 [inline] do_vfs_ioctl+0x1874/0x2100 fs/ioctl.c:849 __do_sys_ioctl fs/ioctl.c:868 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:856 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585