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possible deadlock in wait_transaction_locked

Status: upstream: reported on 2026/01/20 15:21
Reported-by: syzbot+6edd366fa6c02b001539@syzkaller.appspotmail.com
First crash: 10d, last: 3h28m
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in wait_transaction_locked ext4 4 3 603d 622d 0/29 auto-obsoleted due to no activity on 2024/09/14 08:21
linux-6.6 possible deadlock in wait_transaction_locked 4 1 7d22h 7d22h 0/2 upstream: reported on 2026/01/23 09:44
upstream possible deadlock in wait_transaction_locked (3) ext4 4 47 2h30m 31d 0/29 upstream: reported on 2025/12/30 11:48
upstream possible deadlock in wait_transaction_locked (2) ext4 4 1 387d 383d 0/29 auto-obsoleted due to no activity on 2025/04/18 23:41
linux-6.1 possible deadlock in wait_transaction_locked 4 36 5h20m 18d 0/3 upstream: reported on 2026/01/12 10:36

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.7.302/5836 is trying to acquire lock:
ffff888028600990 (jbd2_handle){++++}-{0:0}, at: wait_transaction_locked+0x19f/0x270 fs/jbd2/transaction.c:178

but task is already holding lock:
ffff88807aab04e8 (&journal->j_trans_barrier){.+.+}-{3:3}, at: ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&journal->j_trans_barrier){.+.+}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374
       ocfs2_modify_bh+0xe0/0x4c0 fs/ocfs2/quota_local.c:101
       ocfs2_local_read_info+0x13c8/0x1750 fs/ocfs2/quota_local.c:764
       dquot_load_quota_sb+0x756/0xac0 fs/quota/dquot.c:2463
       dquot_load_quota_inode+0x2d8/0x5d0 fs/quota/dquot.c:2500
       ocfs2_enable_quotas+0x1c5/0x490 fs/ocfs2/super.c:927
       ocfs2_fill_super+0x3cd2/0x50f0 fs/ocfs2/super.c:1140
       mount_bdev+0x287/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x24a/0xa40 fs/namespace.c:3034
       do_mount fs/namespace.c:3377 [inline]
       __do_sys_mount fs/namespace.c:3585 [inline]
       __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #4 (sb_internal#5){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_intwrite include/linux/fs.h:1928 [inline]
       ocfs2_start_trans+0x2a7/0x6f0 fs/ocfs2/journal.c:372
       ocfs2_acquire_dquot+0x688/0xb10 fs/ocfs2/quota_global.c:848
       dqget+0x778/0xeb0 fs/quota/dquot.c:988
       __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517
       ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
       ocfs2_mknod+0x8ab/0x2510 fs/ocfs2/namei.c:310
       ocfs2_mkdir+0x192/0x420 fs/ocfs2/namei.c:657
       vfs_mkdir+0x387/0x570 fs/namei.c:4073
       do_mkdirat+0x1df/0x5b0 fs/namei.c:4098
       __do_sys_mkdirat fs/namei.c:4113 [inline]
       __se_sys_mkdirat fs/namei.c:4111 [inline]
       __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4111
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #3 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ocfs2_create_local_dquot+0x199/0x1850 fs/ocfs2/quota_local.c:1224
       ocfs2_acquire_dquot+0x7ed/0xb10 fs/ocfs2/quota_global.c:871
       dqget+0x778/0xeb0 fs/quota/dquot.c:988
       __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517
       ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
       ocfs2_mknod+0x8ab/0x2510 fs/ocfs2/namei.c:310
       ocfs2_mkdir+0x192/0x420 fs/ocfs2/namei.c:657
       vfs_mkdir+0x387/0x570 fs/namei.c:4073
       do_mkdirat+0x1df/0x5b0 fs/namei.c:4098
       __do_sys_mkdirat fs/namei.c:4113 [inline]
       __se_sys_mkdirat fs/namei.c:4111 [inline]
       __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4111
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #2 (&dquot->dq_lock){+.+.}-{3:3}:
       __mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6210
       mark_dquot_dirty fs/quota/dquot.c:372 [inline]
       mark_all_dquot_dirty+0x1e3/0x400 fs/quota/dquot.c:412
       __dquot_alloc_space+0x5d0/0xe20 fs/quota/dquot.c:1752
       dquot_alloc_space_nodirty include/linux/quotaops.h:297 [inline]
       dquot_alloc_space include/linux/quotaops.h:310 [inline]
       dquot_alloc_block include/linux/quotaops.h:334 [inline]
       ext4_mb_new_blocks+0xf81/0x4980 fs/ext4/mballoc.c:5750
       ext4_ext_map_blocks+0x191c/0x6580 fs/ext4/extents.c:4341
       ext4_map_blocks+0x98e/0x1b30 fs/ext4/inode.c:673
       ext4_alloc_file_blocks+0x378/0xb60 fs/ext4/extents.c:4528
       ext4_zero_range+0x4d4/0xde0 fs/ext4/extents.c:4645
       ext4_fallocate+0x538/0x1ed0 fs/ext4/extents.c:4780
       vfs_fallocate+0x587/0x6f0 fs/open.c:308
       ksys_fallocate fs/open.c:331 [inline]
       __do_sys_fallocate fs/open.c:339 [inline]
       __se_sys_fallocate fs/open.c:337 [inline]
       __x64_sys_fallocate+0xbd/0x100 fs/open.c:337
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (&ei->i_data_sem){++++}-{3:3}:
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       ext4_truncate+0x97f/0x10f0 fs/ext4/inode.c:4251
       ext4_setattr+0xffe/0x19e0 fs/ext4/inode.c:5601
       notify_change+0xbcd/0xee0 fs/attr.c:505
       do_truncate+0x1ac/0x240 fs/open.c:65
       do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (jbd2_handle){++++}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       wait_transaction_locked+0x1bb/0x270 fs/jbd2/transaction.c:178
       add_transaction_credits+0x103/0xc80 fs/jbd2/transaction.c:242
       start_this_handle+0x74d/0x15c0 fs/jbd2/transaction.c:423
       jbd2__journal_start+0x2b7/0x5a0 fs/jbd2/transaction.c:521
       jbd2_journal_start+0x26/0x30 fs/jbd2/transaction.c:560
       ocfs2_start_trans+0x3b2/0x6f0 fs/ocfs2/journal.c:376
       ocfs2_add_inode_to_orphan+0x228/0x7b0 fs/ocfs2/namei.c:2665
       ocfs2_dio_wr_get_block+0x7e6/0x1820 fs/ocfs2/aops.c:2211
       get_more_blocks fs/direct-io.c:673 [inline]
       do_direct_IO fs/direct-io.c:959 [inline]
       do_blockdev_direct_IO fs/direct-io.c:1276 [inline]
       __blockdev_direct_IO+0x13d4/0x3a70 fs/direct-io.c:1368
       ocfs2_direct_IO+0x233/0x2a0 fs/ocfs2/aops.c:2468
       generic_file_direct_write+0x22c/0x490 mm/filemap.c:3687
       __generic_file_write_iter+0x2b1/0x4e0 mm/filemap.c:3869
       ocfs2_file_write_iter+0x1670/0x1e70 fs/ocfs2/file.c:2472
       do_iter_readv_writev+0x47e/0x5f0 fs/read_write.c:-1
       do_iter_write+0x205/0x7b0 fs/read_write.c:855
       iter_file_splice_write+0x699/0xcc0 fs/splice.c:689
       do_splice_from fs/splice.c:767 [inline]
       direct_splice_actor+0xe1/0x130 fs/splice.c:956
       splice_direct_to_actor+0x4ea/0xc10 fs/splice.c:902
       do_splice_direct+0x1d4/0x2f0 fs/splice.c:1008
       do_sendfile+0x5fc/0xeb0 fs/read_write.c:1249
       __do_sys_sendfile64 fs/read_write.c:1317 [inline]
       __se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1303
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  jbd2_handle --> sb_internal#5 --> &journal->j_trans_barrier

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&journal->j_trans_barrier);
                               lock(sb_internal#5);
                               lock(&journal->j_trans_barrier);
  lock(jbd2_handle);

 *** DEADLOCK ***

5 locks held by syz.7.302/5836:
 #0: ffff88807e82e460 (sb_writers#26){.+.+}-{0:0}, at: do_sendfile+0x5d9/0xeb0 fs/read_write.c:1248
 #1: ffff88805f8ec2c8 (&sb->s_type->i_mutex_key#34){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff88805f8ec2c8 (&sb->s_type->i_mutex_key#34){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x436/0x1e70 fs/ocfs2/file.c:2402
 #2: ffff888072715f48 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #2: ffff888072715f48 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]){+.+.}-{3:3}, at: ocfs2_lookup_lock_orphan_dir+0xe9/0x2d0 fs/ocfs2/namei.c:2116
 #3: ffff88807e82e650 (sb_internal#5){.+.+}-{0:0}, at: ocfs2_add_inode_to_orphan+0x228/0x7b0 fs/ocfs2/namei.c:2665
 #4: ffff88807aab04e8 (&journal->j_trans_barrier){.+.+}-{3:3}, at: ocfs2_start_trans+0x3a6/0x6f0 fs/ocfs2/journal.c:374

stack backtrace:
CPU: 0 PID: 5836 Comm: syz.7.302 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 wait_transaction_locked+0x1bb/0x270 fs/jbd2/transaction.c:178
 add_transaction_credits+0x103/0xc80 fs/jbd2/transaction.c:242
 start_this_handle+0x74d/0x15c0 fs/jbd2/transaction.c:423
 jbd2__journal_start+0x2b7/0x5a0 fs/jbd2/transaction.c:521
 jbd2_journal_start+0x26/0x30 fs/jbd2/transaction.c:560
 ocfs2_start_trans+0x3b2/0x6f0 fs/ocfs2/journal.c:376
 ocfs2_add_inode_to_orphan+0x228/0x7b0 fs/ocfs2/namei.c:2665
 ocfs2_dio_wr_get_block+0x7e6/0x1820 fs/ocfs2/aops.c:2211
 get_more_blocks fs/direct-io.c:673 [inline]
 do_direct_IO fs/direct-io.c:959 [inline]
 do_blockdev_direct_IO fs/direct-io.c:1276 [inline]
 __blockdev_direct_IO+0x13d4/0x3a70 fs/direct-io.c:1368
 ocfs2_direct_IO+0x233/0x2a0 fs/ocfs2/aops.c:2468
 generic_file_direct_write+0x22c/0x490 mm/filemap.c:3687
 __generic_file_write_iter+0x2b1/0x4e0 mm/filemap.c:3869
 ocfs2_file_write_iter+0x1670/0x1e70 fs/ocfs2/file.c:2472
 do_iter_readv_writev+0x47e/0x5f0 fs/read_write.c:-1
 do_iter_write+0x205/0x7b0 fs/read_write.c:855
 iter_file_splice_write+0x699/0xcc0 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0xe1/0x130 fs/splice.c:956
 splice_direct_to_actor+0x4ea/0xc10 fs/splice.c:902
 do_splice_direct+0x1d4/0x2f0 fs/splice.c:1008
 do_sendfile+0x5fc/0xeb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1303
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f062b088eb9
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:00007f06292e4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f062b303fa0 RCX: 00007f062b088eb9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007f062b0f6c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f062b304038 R14: 00007f062b303fa0 R15: 00007ffff91db198
 </TASK>
syz.7.302 (5836) used greatest stack depth: 17776 bytes left

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/31 04:34 linux-5.15.y 9eec9a14ee10 c75a2f6e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/01/29 20:24 linux-5.15.y 9eec9a14ee10 aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/01/28 00:19 linux-5.15.y 9eec9a14ee10 3029c699 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/01/24 13:48 linux-5.15.y 9eec9a14ee10 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/01/24 13:47 linux-5.15.y 9eec9a14ee10 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/01/20 18:39 linux-5.15.y 9eec9a14ee10 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
2026/01/20 15:20 linux-5.15.y 9eec9a14ee10 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in wait_transaction_locked
* Struck through repros no longer work on HEAD.