possible deadlock in xfs_dquot_disk_alloc

Status: auto-obsoleted due to no activity on 2025/04/20 08:56
Subsystems: xfs
[Documentation on labels]
Reported-by: syzbot+0f440b139d96ada5b0fd@syzkaller.appspotmail.com
First crash: 612d, last: 552d
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly xfs report (Jan 2025) 0 (1) 2025/01/20 08:14
[syzbot] Monthly xfs report (Dec 2024) 0 (1) 2024/12/21 08:53
[syzbot] [xfs?] possible deadlock in xfs_dquot_disk_alloc 0 (1) 2024/11/24 07:53
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in xfs_dquot_disk_alloc (2) xfs prio:high 4 2 16d 12d 0/29 upstream: reported on 2026/07/12 18:49

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc7-syzkaller-00189-g595523945be0 #0 Not tainted
------------------------------------------------------
kworker/u8:23/13670 is trying to acquire lock:
ffff888059104e98 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_dquot_disk_alloc+0x399/0xe20 fs/xfs/xfs_dquot.c:363

but task is already holding lock:
ffff8880637f4610 (sb_internal#2){.+.+}-{0:0}, at: xfs_dquot_disk_alloc+0x36f/0xe20 fs/xfs/xfs_dquot.c:358

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (sb_internal#2){.+.+}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1725 [inline]
       sb_start_intwrite include/linux/fs.h:1908 [inline]
       xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:266
       xfs_vn_update_time+0x203/0x5f0 fs/xfs/xfs_iops.c:1103
       inode_update_time fs/inode.c:2124 [inline]
       touch_atime+0x27f/0x690 fs/inode.c:2197
       file_accessed include/linux/fs.h:2539 [inline]
       xfs_file_mmap+0x1ab/0x530 fs/xfs/xfs_file.c:1589
       call_mmap include/linux/fs.h:2183 [inline]
       mmap_file mm/internal.h:124 [inline]
       __mmap_new_file_vma mm/vma.c:2291 [inline]
       __mmap_new_vma mm/vma.c:2355 [inline]
       __mmap_region+0x2250/0x2d30 mm/vma.c:2456
       mmap_region+0x226/0x2c0 mm/mmap.c:1352
       do_mmap+0x97a/0x10d0 mm/mmap.c:500
       vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:575
       ksys_mmap_pgoff+0x4eb/0x720 mm/mmap.c:546
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __might_fault+0xc6/0x120 mm/memory.c:6751
       _inline_copy_from_user include/linux/uaccess.h:162 [inline]
       _copy_from_user+0x2a/0xc0 lib/usercopy.c:18
       copy_from_user include/linux/uaccess.h:212 [inline]
       __blk_trace_setup kernel/trace/blktrace.c:626 [inline]
       blk_trace_ioctl+0x1ad/0x9a0 kernel/trace/blktrace.c:740
       blkdev_ioctl+0x40c/0x6a0 block/ioctl.c:682
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&q->debugfs_mutex){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       blk_mq_init_sched+0x3fa/0x830 block/blk-mq-sched.c:473
       elevator_init_mq+0x20e/0x320 block/elevator.c:610
       add_disk_fwnode+0x10d/0xf80 block/genhd.c:413
       sd_probe+0xba6/0x1100 drivers/scsi/sd.c:4024
       really_probe+0x2ba/0xad0 drivers/base/dd.c:658
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
       driver_probe_device+0x50/0x430 drivers/base/dd.c:830
       __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
       bus_for_each_drv+0x250/0x2e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
       async_run_entry_fn+0xaa/0x420 kernel/async.c:129
       process_one_work kernel/workqueue.c:3236 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #3 (&q->q_usage_counter(queue)#50){++++}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       blk_queue_enter+0xe1/0x600 block/blk-core.c:328
       blk_mq_alloc_request+0x4fa/0xaa0 block/blk-mq.c:652
       scsi_alloc_request drivers/scsi/scsi_lib.c:1225 [inline]
       scsi_execute_cmd+0x16c/0x10e0 drivers/scsi/scsi_lib.c:307
       read_capacity_16+0x2b4/0x1450 drivers/scsi/sd.c:2655
       sd_read_capacity drivers/scsi/sd.c:2824 [inline]
       sd_revalidate_disk+0x1013/0xbce0 drivers/scsi/sd.c:3734
       sd_probe+0x9fa/0x1100 drivers/scsi/sd.c:4010
       really_probe+0x2ba/0xad0 drivers/base/dd.c:658
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
       driver_probe_device+0x50/0x430 drivers/base/dd.c:830
       __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
       bus_for_each_drv+0x250/0x2e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
       async_run_entry_fn+0xaa/0x420 kernel/async.c:129
       process_one_work kernel/workqueue.c:3236 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #2 (&q->limits_lock){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       queue_limits_start_update include/linux/blkdev.h:947 [inline]
       loop_reconfigure_limits+0x43f/0x900 drivers/block/loop.c:998
       loop_set_block_size drivers/block/loop.c:1473 [inline]
       lo_simple_ioctl drivers/block/loop.c:1496 [inline]
       lo_ioctl+0x1351/0x1f50 drivers/block/loop.c:1559
       blkdev_ioctl+0x57f/0x6a0 block/ioctl.c:693
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->q_usage_counter(io)#17){++++}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       bio_queue_enter block/blk.h:75 [inline]
       blk_mq_submit_bio+0x1536/0x2390 block/blk-mq.c:3090
       __submit_bio+0x2c6/0x560 block/blk-core.c:629
       __submit_bio_noacct_mq block/blk-core.c:710 [inline]
       submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739
       xfs_buf_ioapply_map+0x461/0x5d0 fs/xfs/xfs_buf.c:1586
       _xfs_buf_ioapply+0x307/0x660 fs/xfs/xfs_buf.c:1674
       __xfs_buf_submit+0x34f/0x7e0 fs/xfs/xfs_buf.c:1758
       xfs_buf_submit fs/xfs/xfs_buf.c:61 [inline]
       _xfs_buf_read fs/xfs/xfs_buf.c:809 [inline]
       xfs_buf_read_map+0x431/0xa50 fs/xfs/xfs_buf.c:873
       xfs_trans_read_buf_map+0x260/0xab0 fs/xfs/xfs_trans_buf.c:304
       xfs_trans_read_buf fs/xfs/xfs_trans.h:213 [inline]
       xfs_read_agf+0x2dc/0x630 fs/xfs/libxfs/xfs_alloc.c:3378
       xfs_alloc_read_agf+0x196/0xbe0 fs/xfs/libxfs/xfs_alloc.c:3413
       xfs_alloc_fix_freelist+0x608/0x1bc0 fs/xfs/libxfs/xfs_alloc.c:2877
       xfs_alloc_vextent_prepare_ag+0xf9/0x6b0 fs/xfs/libxfs/xfs_alloc.c:3543
       xfs_alloc_vextent_iterate_ags+0x141/0x950 fs/xfs/libxfs/xfs_alloc.c:3727
       xfs_alloc_vextent_start_ag+0x3f6/0x950 fs/xfs/libxfs/xfs_alloc.c:3816
       xfs_bmap_btalloc_best_length fs/xfs/libxfs/xfs_bmap.c:3766 [inline]
       xfs_bmap_btalloc fs/xfs/libxfs/xfs_bmap.c:3811 [inline]
       xfs_bmapi_allocate+0x18fa/0x3450 fs/xfs/libxfs/xfs_bmap.c:4224
       xfs_bmapi_write+0xbac/0x1b40 fs/xfs/libxfs/xfs_bmap.c:4553
       xfs_dquot_disk_alloc+0x5f4/0xe20 fs/xfs/xfs_dquot.c:381
       xfs_qm_dqread+0x1a3/0x630 fs/xfs/xfs_dquot.c:720
       xfs_qm_dqget+0x2bb/0x6f0 fs/xfs/xfs_dquot.c:932
       xfs_qm_quotacheck_dqadjust+0xeb/0x5e0 fs/xfs/xfs_qm.c:1331
       xfs_qm_dqusage_adjust+0x5e1/0x850 fs/xfs/xfs_qm.c:1457
       xfs_iwalk_ag_recs+0x4e5/0x820 fs/xfs/xfs_iwalk.c:209
       xfs_iwalk_run_callbacks+0x218/0x470 fs/xfs/xfs_iwalk.c:370
       xfs_iwalk_ag+0xa9a/0xbb0 fs/xfs/xfs_iwalk.c:476
       xfs_iwalk_ag_work+0xfb/0x1b0 fs/xfs/xfs_iwalk.c:625
       xfs_pwork_work+0x81/0x190 fs/xfs/xfs_pwork.c:47
       process_one_work kernel/workqueue.c:3236 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (&xfs_nondir_ilock_class){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693
       xfs_dquot_disk_alloc+0x399/0xe20 fs/xfs/xfs_dquot.c:363
       xfs_qm_dqread+0x1a3/0x630 fs/xfs/xfs_dquot.c:720
       xfs_qm_dqget+0x2bb/0x6f0 fs/xfs/xfs_dquot.c:932
       xfs_qm_quotacheck_dqadjust+0xeb/0x5e0 fs/xfs/xfs_qm.c:1331
       xfs_qm_dqusage_adjust+0x5e1/0x850 fs/xfs/xfs_qm.c:1457
       xfs_iwalk_ag_recs+0x4e5/0x820 fs/xfs/xfs_iwalk.c:209
       xfs_iwalk_run_callbacks+0x218/0x470 fs/xfs/xfs_iwalk.c:370
       xfs_iwalk_ag+0xa9a/0xbb0 fs/xfs/xfs_iwalk.c:476
       xfs_iwalk_ag_work+0xfb/0x1b0 fs/xfs/xfs_iwalk.c:625
       xfs_pwork_work+0x81/0x190 fs/xfs/xfs_pwork.c:47
       process_one_work kernel/workqueue.c:3236 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Chain exists of:
  &xfs_nondir_ilock_class --> &mm->mmap_lock --> sb_internal#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_internal#2);
                               lock(&mm->mmap_lock);
                               lock(sb_internal#2);
  lock(&xfs_nondir_ilock_class);

 *** DEADLOCK ***

3 locks held by kworker/u8:23/13670:
 #0: ffff88805953d148 ((wq_completion)xfs_iwalk-15762){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
 #0: ffff88805953d148 ((wq_completion)xfs_iwalk-15762){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3317
 #1: ffffc9000532fd00 ((work_completion)(&pwork->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
 #1: ffffc9000532fd00 ((work_completion)(&pwork->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3317
 #2: ffff8880637f4610 (sb_internal#2){.+.+}-{0:0}, at: xfs_dquot_disk_alloc+0x36f/0xe20 fs/xfs/xfs_dquot.c:358

stack backtrace:
CPU: 0 UID: 0 PID: 13670 Comm: kworker/u8:23 Not tainted 6.13.0-rc7-syzkaller-00189-g595523945be0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: xfs_iwalk-15762 xfs_pwork_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693
 xfs_dquot_disk_alloc+0x399/0xe20 fs/xfs/xfs_dquot.c:363
 xfs_qm_dqread+0x1a3/0x630 fs/xfs/xfs_dquot.c:720
 xfs_qm_dqget+0x2bb/0x6f0 fs/xfs/xfs_dquot.c:932
 xfs_qm_quotacheck_dqadjust+0xeb/0x5e0 fs/xfs/xfs_qm.c:1331
 xfs_qm_dqusage_adjust+0x5e1/0x850 fs/xfs/xfs_qm.c:1457
 xfs_iwalk_ag_recs+0x4e5/0x820 fs/xfs/xfs_iwalk.c:209
 xfs_iwalk_run_callbacks+0x218/0x470 fs/xfs/xfs_iwalk.c:370
 xfs_iwalk_ag+0xa9a/0xbb0 fs/xfs/xfs_iwalk.c:476
 xfs_iwalk_ag_work+0xfb/0x1b0 fs/xfs/xfs_iwalk.c:625
 xfs_pwork_work+0x81/0x190 fs/xfs/xfs_pwork.c:47
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
bridge0: port 1(bridge_slave_0) entered blocking state
bridge0: port 1(bridge_slave_0) entered forwarding state
bridge0: port 2(bridge_slave_1) entered blocking state
bridge0: port 2(bridge_slave_1) entered forwarding state
bridge0: port 2(bridge_slave_1) entered blocking state
bridge0: port 2(bridge_slave_1) entered forwarding state

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/18 21:56 upstream 595523945be0 f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2025/01/10 11:07 upstream 2144da25584e 67d7ec0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2025/01/04 20:22 upstream 63676eefb7a0 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2024/12/20 15:41 upstream 8faabc041a00 1d58202c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2024/12/15 23:01 upstream 2d8308bf5b67 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2024/12/10 16:18 upstream 7cb1b4663150 cfc402b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2024/11/24 21:54 upstream 9f16d5e6f220 68da6d95 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2024/11/22 08:37 upstream 28eb75e178d3 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2024/11/20 07:49 upstream a5c93bfec0be 7d02db5a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
2024/11/20 07:49 upstream a5c93bfec0be 7d02db5a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in xfs_dquot_disk_alloc
* Struck through repros no longer work on HEAD.