syzbot


possible deadlock in xfs_qm_dqpurge

Status: closed as dup on 2024/04/28 08:08
Subsystems: xfs
[Documentation on labels]
Reported-by: syzbot+a191ccc95425c3409faa@syzkaller.appspotmail.com
First crash: 85d, last: 76d
Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
possible deadlock in xfs_ilock_data_map_shared xfs 1 87d 83d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [xfs?] possible deadlock in xfs_qm_dqpurge 1 (2) 2024/04/28 08:08

Sample crash report:
XFS (loop1): Unmounting Filesystem c496e05e-540d-4c72-b591-04d79d8b4eeb
======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc6-syzkaller-00113-g49a73b1652c5 #0 Not tainted
------------------------------------------------------
syz-executor.1/18641 is trying to acquire lock:
ffffffff8d937100 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:312 [inline]
ffffffff8d937100 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:3746 [inline]
ffffffff8d937100 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:3827 [inline]
ffffffff8d937100 (fs_reclaim){+.+.}-{0:0}, at: kmalloc_trace+0x51/0x330 mm/slub.c:3992

but task is already holding lock:
ffff88805bc46f68 (&xfs_dquot_project_class){+.+.}-{3:3}, at: xfs_dqlock fs/xfs/xfs_dquot.h:125 [inline]
ffff88805bc46f68 (&xfs_dquot_project_class){+.+.}-{3:3}, at: xfs_qm_dqpurge+0xc5/0x630 fs/xfs/xfs_qm.c:129

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&xfs_dquot_project_class){+.+.}-{3:3}:
       __lock_release kernel/locking/lockdep.c:5468 [inline]
       lock_release+0x33e/0x6c0 kernel/locking/lockdep.c:5774
       __mutex_unlock_slowpath+0xa3/0x650 kernel/locking/mutex.c:912
       xfs_qm_dqget_cache_lookup+0x428/0x880 fs/xfs/xfs_dquot.c:802
       xfs_qm_dqget_inode+0x1e7/0x6d0 fs/xfs/xfs_dquot.c:994
       xfs_qm_dqattach_one+0x26f/0x590 fs/xfs/xfs_qm.c:278
       xfs_qm_dqattach_locked+0x1a8/0x2d0 fs/xfs/xfs_qm.c:345
       xfs_qm_vop_dqalloc+0x344/0xe40 fs/xfs/xfs_qm.c:1710
       xfs_create+0x422/0x1170 fs/xfs/xfs_inode.c:1041
       xfs_generic_create+0x631/0x7c0 fs/xfs/xfs_iops.c:199
       lookup_open.isra.0+0x10a1/0x13c0 fs/namei.c:3497
       open_last_lookups fs/namei.c:3566 [inline]
       path_openat+0x92f/0x2990 fs/namei.c:3796
       do_filp_open+0x1dc/0x430 fs/namei.c:3826
       do_sys_openat2+0x17a/0x1e0 fs/open.c:1406
       do_sys_open fs/open.c:1421 [inline]
       __do_compat_sys_openat fs/open.c:1481 [inline]
       __se_compat_sys_openat fs/open.c:1479 [inline]
       __ia32_compat_sys_openat+0x16e/0x210 fs/open.c:1479
       do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
       __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
       do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

-> #1 (&xfs_dir_ilock_class){++++}-{3:3}:
       down_write_nested+0x3d/0x50 kernel/locking/rwsem.c:1695
       xfs_ilock+0x2ef/0x420 fs/xfs/xfs_inode.c:206
       xfs_reclaim_inode fs/xfs/xfs_icache.c:945 [inline]
       xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1631 [inline]
       xfs_icwalk_ag+0xca6/0x1780 fs/xfs/xfs_icache.c:1713
       xfs_icwalk+0x57/0x100 fs/xfs/xfs_icache.c:1762
       xfs_reclaim_inodes_nr+0x182/0x250 fs/xfs/xfs_icache.c:1011
       super_cache_scan+0x409/0x550 fs/super.c:227
       do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435
       shrink_slab+0x18a/0x1310 mm/shrinker.c:662
       shrink_one+0x493/0x7c0 mm/vmscan.c:4774
       shrink_many mm/vmscan.c:4835 [inline]
       lru_gen_shrink_node+0x89f/0x1750 mm/vmscan.c:4935
       shrink_node mm/vmscan.c:5894 [inline]
       kswapd_shrink_node mm/vmscan.c:6704 [inline]
       balance_pgdat+0x10d1/0x1a10 mm/vmscan.c:6895
       kswapd+0x5ea/0xbf0 mm/vmscan.c:7164
       kthread+0x2c1/0x3a0 kernel/kthread.c:388
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (fs_reclaim){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
       lock_acquire kernel/locking/lockdep.c:5754 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
       __fs_reclaim_acquire mm/page_alloc.c:3698 [inline]
       fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3712
       might_alloc include/linux/sched/mm.h:312 [inline]
       slab_pre_alloc_hook mm/slub.c:3746 [inline]
       slab_alloc_node mm/slub.c:3827 [inline]
       kmalloc_trace+0x51/0x330 mm/slub.c:3992
       kmalloc include/linux/slab.h:628 [inline]
       add_stack_record_to_list mm/page_owner.c:177 [inline]
       inc_stack_record_count mm/page_owner.c:219 [inline]
       __set_page_owner+0x517/0x7a0 mm/page_owner.c:334
       set_page_owner include/linux/page_owner.h:32 [inline]
       post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534
       prep_new_page mm/page_alloc.c:1541 [inline]
       get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317
       __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575
       __alloc_pages_bulk+0x742/0x14f0 mm/page_alloc.c:4523
       alloc_pages_bulk_array include/linux/gfp.h:202 [inline]
       xfs_buf_alloc_pages+0x20f/0x9d0 fs/xfs/xfs_buf.c:398
       xfs_buf_find_insert fs/xfs/xfs_buf.c:650 [inline]
       xfs_buf_get_map+0x1e69/0x30d0 fs/xfs/xfs_buf.c:755
       xfs_buf_read_map+0xd2/0xb40 fs/xfs/xfs_buf.c:860
       xfs_trans_read_buf_map+0x352/0x990 fs/xfs/xfs_trans_buf.c:289
       xfs_trans_read_buf fs/xfs/xfs_trans.h:210 [inline]
       xfs_qm_dqflush+0x224/0x1470 fs/xfs/xfs_dquot.c:1271
       xfs_qm_dqpurge+0x1d3/0x630 fs/xfs/xfs_qm.c:149
       xfs_qm_dquot_walk.isra.0+0x217/0x3d0 fs/xfs/xfs_qm.c:88
       xfs_qm_dqpurge_all fs/xfs/xfs_qm.c:195 [inline]
       xfs_qm_unmount+0xc7/0x1c0 fs/xfs/xfs_qm.c:206
       xfs_unmountfs+0x76/0x240 fs/xfs/xfs_mount.c:1076
       xfs_fs_put_super+0x61/0x160 fs/xfs/xfs_super.c:1134
       generic_shutdown_super+0x159/0x3d0 fs/super.c:641
       kill_block_super+0x3b/0x90 fs/super.c:1675
       xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2026
       deactivate_locked_super+0xbe/0x1a0 fs/super.c:472
       deactivate_super+0xde/0x100 fs/super.c:505
       cleanup_mnt+0x222/0x450 fs/namespace.c:1267
       task_work_run+0x14e/0x250 kernel/task_work.c:180
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0xa7d/0x2c10 kernel/exit.c:878
       do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
       __do_sys_exit_group kernel/exit.c:1038 [inline]
       __se_sys_exit_group kernel/exit.c:1036 [inline]
       __ia32_sys_exit_group+0x3e/0x50 kernel/exit.c:1036
       do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
       __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
       do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

other info that might help us debug this:

Chain exists of:
  fs_reclaim --> &xfs_dir_ilock_class --> &xfs_dquot_project_class

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&xfs_dquot_project_class);
                               lock(&xfs_dir_ilock_class);
                               lock(&xfs_dquot_project_class);
  lock(fs_reclaim);

 *** DEADLOCK ***

3 locks held by syz-executor.1/18641:
 #0: ffff88801ceac0e0 (&type->s_umount_key#73){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88801ceac0e0 (&type->s_umount_key#73){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88801ceac0e0 (&type->s_umount_key#73){++++}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:504
 #1: ffff8880127fe158 (&qinf->qi_tree_lock){+.+.}-{3:3}, at: xfs_qm_dquot_walk.isra.0+0x111/0x3d0 fs/xfs/xfs_qm.c:75
 #2: ffff88805bc46f68 (&xfs_dquot_project_class){+.+.}-{3:3}, at: xfs_dqlock fs/xfs/xfs_dquot.h:125 [inline]
 #2: ffff88805bc46f68 (&xfs_dquot_project_class){+.+.}-{3:3}, at: xfs_qm_dqpurge+0xc5/0x630 fs/xfs/xfs_qm.c:129

stack backtrace:
CPU: 0 PID: 18641 Comm: syz-executor.1 Not tainted 6.9.0-rc6-syzkaller-00113-g49a73b1652c5 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137
 lock_acquire kernel/locking/lockdep.c:5754 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719
 __fs_reclaim_acquire mm/page_alloc.c:3698 [inline]
 fs_reclaim_acquire+0x102/0x160 mm/page_alloc.c:3712
 might_alloc include/linux/sched/mm.h:312 [inline]
 slab_pre_alloc_hook mm/slub.c:3746 [inline]
 slab_alloc_node mm/slub.c:3827 [inline]
 kmalloc_trace+0x51/0x330 mm/slub.c:3992
 kmalloc include/linux/slab.h:628 [inline]
 add_stack_record_to_list mm/page_owner.c:177 [inline]
 inc_stack_record_count mm/page_owner.c:219 [inline]
 __set_page_owner+0x517/0x7a0 mm/page_owner.c:334
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317
 __alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575
 __alloc_pages_bulk+0x742/0x14f0 mm/page_alloc.c:4523
 alloc_pages_bulk_array include/linux/gfp.h:202 [inline]
 xfs_buf_alloc_pages+0x20f/0x9d0 fs/xfs/xfs_buf.c:398
 xfs_buf_find_insert fs/xfs/xfs_buf.c:650 [inline]
 xfs_buf_get_map+0x1e69/0x30d0 fs/xfs/xfs_buf.c:755
 xfs_buf_read_map+0xd2/0xb40 fs/xfs/xfs_buf.c:860
 xfs_trans_read_buf_map+0x352/0x990 fs/xfs/xfs_trans_buf.c:289
 xfs_trans_read_buf fs/xfs/xfs_trans.h:210 [inline]
 xfs_qm_dqflush+0x224/0x1470 fs/xfs/xfs_dquot.c:1271
 xfs_qm_dqpurge+0x1d3/0x630 fs/xfs/xfs_qm.c:149
 xfs_qm_dquot_walk.isra.0+0x217/0x3d0 fs/xfs/xfs_qm.c:88
 xfs_qm_dqpurge_all fs/xfs/xfs_qm.c:195 [inline]
 xfs_qm_unmount+0xc7/0x1c0 fs/xfs/xfs_qm.c:206
 xfs_unmountfs+0x76/0x240 fs/xfs/xfs_mount.c:1076
 xfs_fs_put_super+0x61/0x160 fs/xfs/xfs_super.c:1134
 generic_shutdown_super+0x159/0x3d0 fs/super.c:641
 kill_block_super+0x3b/0x90 fs/super.c:1675
 xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2026
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:472
 deactivate_super+0xde/0x100 fs/super.c:505
 cleanup_mnt+0x222/0x450 fs/namespace.c:1267
 task_work_run+0x14e/0x250 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xa7d/0x2c10 kernel/exit.c:878
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1027
 __do_sys_exit_group kernel/exit.c:1038 [inline]
 __se_sys_exit_group kernel/exit.c:1036 [inline]
 __ia32_sys_exit_group+0x3e/0x50 kernel/exit.c:1036
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x75/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf734b579
Code: Unable to access opcode bytes at 0xf734b54f.
RSP: 002b:00000000ff94901c EFLAGS: 00000286 ORIG_RAX: 00000000000000fc
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000ff949120
RDX: 00000000f7377097 RSI: 0000000000000000 RDI: 00000000f73f21b5
RBP: 00000000ff949078 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/03 04:08 upstream 49a73b1652c5 22ee48a2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in xfs_qm_dqpurge
2024/04/30 04:39 upstream b947cc5bf6d7 f10afd69 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in xfs_qm_dqpurge
2024/04/24 07:10 upstream 9d1ddab261f3 21339d7b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in xfs_qm_dqpurge
* Struck through repros no longer work on HEAD.