gfs2: fsid=syz:syz.0: first mount done, others may mount gfs2: fsid=syz:syz.0: found 2 quota changes ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.356/6072 is trying to acquire lock: ffff0000d8518ae0 (&sdp->sd_quota_mutex){+.+.}-{3:3}, at: do_qc+0xbc/0x648 fs/gfs2/quota.c:682 but task is already holding lock: ffff0000f50e4260 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1529 [inline] ffff0000f50e4260 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x20d8/0x2e88 fs/gfs2/bmap.c:1854 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 punch_hole+0x2968/0x2e88 fs/gfs2/bmap.c:1955 gfs2_iomap_end+0x4c8/0x694 fs/gfs2/bmap.c:1174 iomap_iter+0x1d0/0x10e0 fs/iomap/iter.c:79 iomap_file_buffered_write+0x5a0/0x6b8 fs/iomap/buffered-io.c:846 gfs2_file_buffered_write+0x488/0x7e8 fs/gfs2/file.c:1057 gfs2_file_write_iter+0x3f0/0xc1c fs/gfs2/file.c:1158 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x3ec/0x7f0 fs/read_write.c:584 ksys_write+0x12c/0x224 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __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 *** 6 locks held by syz.4.356/6072: #0: ffff0000d59fe368 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x114/0x16c fs/file.c:1038 #1: ffff0000d13ac460 (sb_writers#19){.+.+}-{0:0}, at: vfs_write+0x244/0x7f0 fs/read_write.c:580 #2: ffff0000f50e3dc8 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #2: ffff0000f50e3dc8 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: gfs2_file_write_iter+0x2cc/0xc1c fs/gfs2/file.c:1115 #3: ffff0000d13ac650 (sb_internal#6){.+.+}-{0:0}, at: gfs2_trans_begin+0xa8/0x114 fs/gfs2/trans.c:118 #4: ffff0000d8519058 (&sdp->sd_log_flush_lock){++++}-{3:3}, at: __gfs2_trans_begin+0x500/0x870 fs/gfs2/trans.c:87 #5: ffff0000f50e4260 (&ip->i_rw_mutex){++++}-{3:3}, at: sweep_bh_for_rgrps fs/gfs2/bmap.c:1529 [inline] #5: ffff0000f50e4260 (&ip->i_rw_mutex){++++}-{3:3}, at: punch_hole+0x20d8/0x2e88 fs/gfs2/bmap.c:1854 stack backtrace: CPU: 0 PID: 6072 Comm: syz.4.356 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 punch_hole+0x2968/0x2e88 fs/gfs2/bmap.c:1955 gfs2_iomap_end+0x4c8/0x694 fs/gfs2/bmap.c:1174 iomap_iter+0x1d0/0x10e0 fs/iomap/iter.c:79 iomap_file_buffered_write+0x5a0/0x6b8 fs/iomap/buffered-io.c:846 gfs2_file_buffered_write+0x488/0x7e8 fs/gfs2/file.c:1057 gfs2_file_write_iter+0x3f0/0xc1c fs/gfs2/file.c:1158 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x3ec/0x7f0 fs/read_write.c:584 ksys_write+0x12c/0x224 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __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