possible deadlock in ocfs2_remove_btree_range

Status: upstream: reported on 2026/01/29 20:10
Reported-by: syzbot+69c0df05e9a71a6ea62e@syzkaller.appspotmail.com
First crash: 233d, last: 3d14h
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in ocfs2_remove_btree_range (2) ocfs2 4 1 319d 315d 0/29 auto-obsoleted due to no activity on 2026/02/13 02:43
linux-5.15 possible deadlock in ocfs2_remove_btree_range (3) 4 2 37d 54d 0/3 upstream: reported on 2026/07/28 02:59
linux-5.15 possible deadlock in ocfs2_remove_btree_range (2) 4 4 159d 224d 0/3 auto-obsoleted due to no activity on 2026/07/23 14:33
linux-5.15 possible deadlock in ocfs2_remove_btree_range 4 1 735d 735d 0/3 auto-obsoleted due to no activity on 2024/12/24 02:14
upstream possible deadlock in ocfs2_remove_btree_range ocfs2 4 2 665d 692d 0/29 auto-obsoleted due to no activity on 2025/03/03 19:57

Sample crash report:
ocfs2: Mounting device (7,4) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.4.172/4789 is trying to acquire lock:
ffff888054b7a648 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline]
ffff888054b7a648 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: ocfs2_remove_btree_range+0x64f/0x15e0 fs/ocfs2/alloc.c:5742

but task is already holding lock:
ffff8880723c4da0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x365/0x1660 fs/ocfs2/file.c:467

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       ocfs2_create_local_dquot+0x19a/0x1900 fs/ocfs2/quota_local.c:1224
       ocfs2_acquire_dquot+0x7e6/0xb80 fs/ocfs2/quota_global.c:871
       dqget+0x713/0xbb0 fs/quota/dquot.c:1013
       __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1542
       ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
       ocfs2_mknod+0xbe8/0x25e0 fs/ocfs2/namei.c:311
       ocfs2_create+0x1b6/0x4b0 fs/ocfs2/namei.c:681
       lookup_open fs/namei.c:3533 [inline]
       open_last_lookups fs/namei.c:3601 [inline]
       path_openat+0x11b9/0x2f10 fs/namei.c:3831
       do_filp_open+0x1ee/0x420 fs/namei.c:3861
       do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
       do_sys_open fs/open.c:1336 [inline]
       __do_sys_creat fs/open.c:1414 [inline]
       __se_sys_creat fs/open.c:1408 [inline]
       __x64_sys_creat+0x8c/0xb0 fs/open.c:1408
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #3 (&dquot->dq_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747
       dquot_commit+0x5a/0x410 fs/quota/dquot.c:535
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817
       mark_dquot_dirty fs/quota/dquot.c:400 [inline]
       mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440
       __dquot_alloc_space+0x5f6/0xe50 fs/quota/dquot.c:1777
       dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline]
       dquot_alloc_space include/linux/quotaops.h:306 [inline]
       dquot_alloc_block include/linux/quotaops.h:330 [inline]
       ext4_mb_new_blocks+0xf55/0x44d0 fs/ext4/mballoc.c:5740
       ext4_ext_map_blocks+0x18d1/0x6640 fs/ext4/extents.c:4361
       ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681
       _ext4_get_block+0x1e7/0x540 fs/ext4/inode.c:824
       ext4_block_write_begin+0x63b/0x12f0 fs/ext4/inode.c:1126
       ext4_write_begin+0x623/0xf40 fs/ext4/ext4_jbd2.h:-1
       ext4_da_write_begin+0x408/0x920 fs/ext4/inode.c:3002
       generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
       ext4_buffered_write_iter+0x11a/0x380 fs/ext4/file.c:292
       ext4_file_write_iter+0x1e3/0x17d0 fs/ext4/file.c:-1
       call_write_iter include/linux/fs.h:2271 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x482/0x9a0 fs/read_write.c:584
       ksys_pwrite64 fs/read_write.c:699 [inline]
       __do_sys_pwrite64 fs/read_write.c:709 [inline]
       __se_sys_pwrite64 fs/read_write.c:706 [inline]
       __x64_sys_pwrite64+0x194/0x220 fs/read_write.c:706
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (&ei->i_data_sem){++++}-{3:3}:
       down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520
       ext4_map_blocks+0x338/0x1a90 fs/ext4/inode.c:606
       ext4_append+0x22d/0x560 fs/ext4/namei.c:75
       ext4_init_new_dir+0x2b8/0x550 fs/ext4/namei.c:3032
       ext4_mkdir+0x4c3/0xc90 fs/ext4/namei.c:3078
       vfs_mkdir+0x386/0x570 fs/namei.c:4157
       do_mkdirat+0x1d8/0x440 fs/namei.c:4182
       __do_sys_mkdir fs/namei.c:4202 [inline]
       __se_sys_mkdir fs/namei.c:4200 [inline]
       __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4200
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (jbd2_handle){++++}-{0:0}:
       jbd2_journal_lock_updates+0xa8/0x390 fs/jbd2/transaction.c:880
       __ocfs2_flush_truncate_log+0x2cf/0x1220 fs/ocfs2/alloc.c:6029
       ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6076
       ocfs2_sync_fs+0x119/0x330 fs/ocfs2/super.c:402
       sync_filesystem+0x1be/0x220 fs/sync.c:66
       generic_shutdown_super+0x6b/0x340 fs/super.c:474
       kill_block_super+0x7c/0xe0 fs/super.c:1481
       deactivate_locked_super+0x93/0xf0 fs/super.c:332
       cleanup_mnt+0x471/0x4f0 fs/namespace.c:1191
       task_work_run+0x1d0/0x260 kernel/task_work.c:203
       resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
       exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:180
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213
       __syscall_exit_to_user_mode_work kernel/entry/common.c:295 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:306
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3830 [inline]
       __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
       lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5678
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:764 [inline]
       ocfs2_remove_btree_range+0x64f/0x15e0 fs/ocfs2/alloc.c:5742
       ocfs2_commit_truncate+0xba2/0x1e00 fs/ocfs2/alloc.c:7353
       ocfs2_truncate_file+0xdf0/0x1660 fs/ocfs2/file.c:505
       ocfs2_setattr+0x16f8/0x1d90 fs/ocfs2/file.c:1212
       notify_change+0xca0/0xf90 fs/attr.c:499
       do_truncate+0x1ac/0x240 fs/open.c:65
       handle_truncate fs/namei.c:3336 [inline]
       do_open fs/namei.c:3681 [inline]
       path_openat+0x2897/0x2f10 fs/namei.c:3834
       do_filp_open+0x1ee/0x420 fs/namei.c:3861
       do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
       do_sys_open fs/open.c:1336 [inline]
       __do_sys_openat fs/open.c:1352 [inline]
       __se_sys_openat fs/open.c:1347 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1347
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
  &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7 --> &dquot->dq_lock --> &ocfs2_quota_ip_alloc_sem_key

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ocfs2_quota_ip_alloc_sem_key);
                               lock(&dquot->dq_lock);
                               lock(&ocfs2_quota_ip_alloc_sem_key);
  lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7);

 *** DEADLOCK ***

3 locks held by syz.4.172/4789:
 #0: ffff88814472c460 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
 #1: ffff8880723c5108 (&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:764 [inline]
 #1: ffff8880723c5108 (&sb->s_type->i_mutex_key#23){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
 #2: ffff8880723c4da0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x365/0x1660 fs/ocfs2/file.c:467

stack backtrace:
CPU: 0 PID: 4789 Comm: syz.4.172 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3830 [inline]
 __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5678
 down_write+0x36/0x60 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:764 [inline]
 ocfs2_remove_btree_range+0x64f/0x15e0 fs/ocfs2/alloc.c:5742
 ocfs2_commit_truncate+0xba2/0x1e00 fs/ocfs2/alloc.c:7353
 ocfs2_truncate_file+0xdf0/0x1660 fs/ocfs2/file.c:505
 ocfs2_setattr+0x16f8/0x1d90 fs/ocfs2/file.c:1212
 notify_change+0xca0/0xf90 fs/attr.c:499
 do_truncate+0x1ac/0x240 fs/open.c:65
 handle_truncate fs/namei.c:3336 [inline]
 do_open fs/namei.c:3681 [inline]
 path_openat+0x2897/0x2f10 fs/namei.c:3834
 do_filp_open+0x1ee/0x420 fs/namei.c:3861
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0aee99e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0aef8e9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0aeec25fa0 RCX: 00007f0aee99e159
RDX: 000000000000275a RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f0aeea3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0aeec26038 R14: 00007f0aeec25fa0 R15: 00007ffc106ebae8
 </TASK>

Crashes (24):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/17 00:55 linux-6.1.y 1a8763b93150 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/09/17 00:55 linux-6.1.y 1a8763b93150 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/09/14 17:28 linux-6.1.y 1a8763b93150 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/07/28 04:17 linux-6.1.y dc5c83b7f5f8 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/04/15 16:08 linux-6.1.y 8e8fc038cad5 c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/03/12 21:01 linux-6.1.y f2ddafa93a25 4efadf07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/02/07 22:19 linux-6.1.y 0182cb5b74ee 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/02/06 07:08 linux-6.1.y cd9b81672742 f03c4191 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in ocfs2_remove_btree_range
2026/08/31 02:37 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/08/18 19:16 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/08/08 13:14 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/08/08 13:09 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/08/08 13:06 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/08/06 20:34 linux-6.1.y 03f3a99e8e93 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/06/03 17:00 linux-6.1.y 228da13e907e 234057e5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/05/29 20:45 linux-6.1.y dcbcab9d7079 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/04/04 10:43 linux-6.1.y 1989cd3d56e2 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/03/06 17:25 linux-6.1.y f2ddafa93a25 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/03/02 15:35 linux-6.1.y 779f9571ac3e b9dd6534 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/02/21 19:54 linux-6.1.y 779f9571ac3e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/02/10 13:38 linux-6.1.y 0182cb5b74ee 91d776d3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/02/07 14:14 linux-6.1.y 0182cb5b74ee f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/02/05 11:14 linux-6.1.y cd9b81672742 4936e85c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
2026/01/29 20:10 linux-6.1.y cd9b81672742 aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in ocfs2_remove_btree_range
* Struck through repros no longer work on HEAD.