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possible deadlock in filename_create (2)

Status: upstream: reported C repro on 2024/03/30 13:42
Bug presence: origin:lts-only
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+b6f2fe752b6507098b78@syzkaller.appspotmail.com
First crash: 451d, last: 10d
Fix bisection: failed (error log, bisect log)
  
Bug presence (2)
Date Name Commit Repro Result
2025/06/15 linux-5.15.y (ToT) 1c700860e8bc C [report] possible deadlock in filename_create
2025/06/15 upstream (ToT) 8c6bc74c7f89 C Didn't crash
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 possible deadlock in filename_create reiserfs 1 862d 862d 0/1 upstream: reported on 2023/02/13 11:59
linux-5.15 possible deadlock in filename_create 23 608d 831d 0/3 auto-obsoleted due to no activity on 2024/02/02 20:22
linux-6.1 possible deadlock in filename_create 15 618d 819d 0/3 auto-obsoleted due to no activity on 2024/01/23 21:11
linux-6.1 possible deadlock in filename_create (2) origin:upstream missing-backport C done 19 14d 479d 0/3 upstream: reported C repro on 2024/03/02 21:45
linux-4.14 possible deadlock in filename_create reiserfs 1 896d 896d 0/1 upstream: reported on 2023/01/10 15:41
upstream possible deadlock in filename_create reiserfs C 97 527d 958d 0/29 auto-obsoleted due to no activity on 2024/03/25 04:40
Last patch testing requests (6)
Created Duration User Patch Repo Result
2025/05/11 15:59 27m retest repro linux-5.15.y report log
2025/05/11 15:59 29m retest repro linux-5.15.y report log
2025/04/06 01:03 13m retest repro linux-5.15.y report log
2025/04/06 01:03 11m retest repro linux-5.15.y report log
2025/02/24 10:14 58m retest repro linux-5.15.y report log
2025/02/24 10:14 13m retest repro linux-5.15.y report log
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2025/03/17 01:53 1m fix candidate upstream error job log
2024/06/12 12:23 5m bisect fix linux-5.15.y error job log

Sample crash report:
REISERFS (device loop3): checking transaction log (loop3)
REISERFS (device loop3): Using tea hash to sort names
REISERFS (device loop3): Created .reiserfs_priv - reserved for xattr storage.
======================================================
WARNING: possible circular locking dependency detected
5.15.185-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor739/4205 is trying to acquire lock:
ffff88806f51c520 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:822 [inline]
ffff88806f51c520 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x1f2/0x450 fs/namei.c:3835

but task is already holding lock:
ffff888023118460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:377

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#9){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_write+0x4f/0x1c0 include/linux/fs.h:1881
       mnt_want_write_file+0x5c/0x200 fs/namespace.c:421
       reiserfs_ioctl+0x10a/0x330 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
       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 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       reiserfs_write_lock+0x75/0xd0 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x137/0x420 fs/reiserfs/namei.c:364
       lookup_one_qstr_excl+0x10e/0x240 fs/namei.c:1563
       filename_create+0x21e/0x450 fs/namei.c:3836
       do_mkdirat+0x9d/0x5a0 fs/namei.c:4080
       __do_sys_mkdirat fs/namei.c:4105 [inline]
       __se_sys_mkdirat fs/namei.c:4103 [inline]
       __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4103
       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 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}:
       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+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       down_write_nested+0x3b/0x60 kernel/locking/rwsem.c:1667
       inode_lock_nested include/linux/fs.h:822 [inline]
       filename_create+0x1f2/0x450 fs/namei.c:3835
       do_mkdirat+0x9d/0x5a0 fs/namei.c:4080
       __do_sys_mkdirat fs/namei.c:4105 [inline]
       __se_sys_mkdirat fs/namei.c:4103 [inline]
       __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4103
       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:
  &type->i_mutex_dir_key#6/1 --> &sbi->lock --> sb_writers#9

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#9);
                               lock(&sbi->lock);
                               lock(sb_writers#9);
  lock(&type->i_mutex_dir_key#6/1);

 *** DEADLOCK ***

1 lock held by syz-executor739/4205:
 #0: ffff888023118460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:377

stack backtrace:
CPU: 1 PID: 4205 Comm: syz-executor739 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 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+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 down_write_nested+0x3b/0x60 kernel/locking/rwsem.c:1667
 inode_lock_nested include/linux/fs.h:822 [inline]
 filename_create+0x1f2/0x450 fs/namei.c:3835
 do_mkdirat+0x9d/0x5a0 fs/namei.c:4080
 __do_sys_mkdirat fs/namei.c:4105 [inline]
 __se_sys_mkdirat fs/namei.c:4103 [inline]
 __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4103
 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: 0033:0x7fa15e8a0459
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff82debce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fa15e8a0459
RDX: 0000000000000000 RSI: 0000200000000180 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000001119 R09: 0000200000002300
R10: 00007fff82debbb0 R11: 0000000000000246 R12: 00007fff82debd1c
R13: 0000000000000002 R14: 431bde82d7b634db R15: 00007fff82debd50
 </TASK>

Crashes (24):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/09 11:03 linux-5.15.y 1c700860e8bc 4826c28e .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-5-15-kasan possible deadlock in filename_create
2025/03/05 06:11 linux-5.15.y c16c81c81336 c3901742 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2025/02/10 02:34 linux-5.15.y c16c81c81336 ef44b750 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1 (corrupt fs)] [mounted in repro #2 (corrupt fs)] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/04/20 18:33 linux-5.15.y c52b9710c83d af24b050 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/03/30 14:27 linux-5.15.y 9465fef4ae35 6baf5069 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2025/03/21 21:19 linux-5.15.y 0c935c049b5c c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in filename_create
2025/03/20 20:02 linux-5.15.y 0c935c049b5c 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in filename_create
2025/03/19 07:56 linux-5.15.y 0c935c049b5c 8d0a2921 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in filename_create
2025/03/18 15:45 linux-5.15.y 0c935c049b5c 22a6c2b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in filename_create
2025/03/18 15:45 linux-5.15.y 0c935c049b5c 22a6c2b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in filename_create
2024/04/30 23:43 linux-5.15.y b925f60c6ee7 3ce4924c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in filename_create
2025/06/08 11:27 linux-5.15.y 1c700860e8bc 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2025/06/08 11:25 linux-5.15.y 1c700860e8bc 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2025/04/25 05:42 linux-5.15.y f7347f400572 e3715315 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2025/04/25 05:42 linux-5.15.y f7347f400572 e3715315 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2025/04/24 19:47 linux-5.15.y f7347f400572 9882047a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2025/04/24 19:46 linux-5.15.y f7347f400572 9882047a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/05/13 05:04 linux-5.15.y 284087d4f7d5 9026e142 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/05/12 15:10 linux-5.15.y 284087d4f7d5 9026e142 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/04/23 02:18 linux-5.15.y c52b9710c83d 36c961ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/04/21 09:04 linux-5.15.y c52b9710c83d af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/03/31 17:57 linux-5.15.y 9465fef4ae35 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/03/30 13:41 linux-5.15.y 9465fef4ae35 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
2024/03/30 13:41 linux-5.15.y 9465fef4ae35 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 possible deadlock in filename_create
* Struck through repros no longer work on HEAD.