syzbot


possible deadlock in filename_create (2)

Status: upstream: reported C repro on 2024/03/02 21:45
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+6002e4561fb277938809@syzkaller.appspotmail.com
First crash: 104d, last: 10d
Bug presence (1)
Date Name Commit Repro Result
2024/03/02 upstream (ToT) 04b8076df253 C [report] possible deadlock in filename_create
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 488d 488d 0/1 upstream: reported on 2023/02/13 11:59
linux-5.15 possible deadlock in filename_create 23 233d 456d 0/3 auto-obsoleted due to no activity on 2024/02/02 20:22
linux-6.1 possible deadlock in filename_create 15 243d 445d 0/3 auto-obsoleted due to no activity on 2024/01/23 21:11
linux-4.14 possible deadlock in filename_create reiserfs 1 522d 522d 0/1 upstream: reported on 2023/01/10 15:41
linux-5.15 possible deadlock in filename_create (2) origin:upstream C error 10 33d 77d 0/3 upstream: reported C repro on 2024/03/30 13:42
upstream possible deadlock in filename_create reiserfs C 97 152d 584d 0/27 auto-obsoleted due to no activity on 2024/03/25 04:40
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2024/06/04 20:36 1h36m bisect fix linux-6.1.y job log (0) log
2024/04/01 21:50 2h26m bisect fix linux-6.1.y job log (0) log

Sample crash report:
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
6.1.80-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor344/6785 is trying to acquire lock:
ffff0000e2596640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
ffff0000e2596640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x204/0x468 fs/namei.c:3878

but task is already holding lock:
ffff0000dbe14460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#8){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1877 [inline]
       sb_start_write+0x7c/0x308 include/linux/fs.h:1952
       mnt_want_write_file+0x64/0x1e8 fs/namespace.c:437
       reiserfs_ioctl+0x184/0x454 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl fs/ioctl.c:856 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (&sbi->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
       reiserfs_lookup+0x130/0x3c4 fs/reiserfs/namei.c:364
       lookup_one_qstr_excl+0x108/0x230 fs/namei.c:1605
       filename_create+0x230/0x468 fs/namei.c:3879
       do_mkdirat+0xac/0x510 fs/namei.c:4123
       __do_sys_mkdirat fs/namei.c:4148 [inline]
       __se_sys_mkdirat fs/namei.c:4146 [inline]
       __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4146
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
       lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
       down_write_nested+0x64/0x94 kernel/locking/rwsem.c:1689
       inode_lock_nested include/linux/fs.h:793 [inline]
       filename_create+0x204/0x468 fs/namei.c:3878
       do_mkdirat+0xac/0x510 fs/namei.c:4123
       __do_sys_mkdirat fs/namei.c:4148 [inline]
       __se_sys_mkdirat fs/namei.c:4146 [inline]
       __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4146
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
  &type->i_mutex_dir_key#6/1 --> &sbi->lock --> sb_writers#8

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#8);
                               lock(&sbi->lock);
                               lock(sb_writers#8);
  lock(&type->i_mutex_dir_key#6/1);

 *** DEADLOCK ***

1 lock held by syz-executor344/6785:
 #0: ffff0000dbe14460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393

stack backtrace:
CPU: 0 PID: 6785 Comm: syz-executor344 Not tainted 6.1.80-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2048
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
 down_write_nested+0x64/0x94 kernel/locking/rwsem.c:1689
 inode_lock_nested include/linux/fs.h:793 [inline]
 filename_create+0x204/0x468 fs/namei.c:3878
 do_mkdirat+0xac/0x510 fs/namei.c:4123
 __do_sys_mkdirat fs/namei.c:4148 [inline]
 __se_sys_mkdirat fs/namei.c:4146 [inline]
 __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4146
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/02 21:44 linux-6.1.y a3eb3a74aa8c 25905f5d .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/27 20:15 linux-6.1.y f2295faba5e8 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in filename_create
2024/05/03 12:09 linux-6.1.y 909ba1f1b414 dd26401e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/30 12:17 linux-6.1.y dcbc050cb0d3 3ce4924c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/29 12:36 linux-6.1.y dcbc050cb0d3 27e33c58 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/29 12:36 linux-6.1.y dcbc050cb0d3 27e33c58 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/29 12:36 linux-6.1.y dcbc050cb0d3 27e33c58 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/29 00:30 linux-6.1.y f2295faba5e8 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/27 05:04 linux-6.1.y 6741e066ec76 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/22 13:19 linux-6.1.y 6741e066ec76 36c961ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/22 05:28 linux-6.1.y 6741e066ec76 af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/19 16:10 linux-6.1.y 6741e066ec76 af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
2024/04/02 15:26 linux-6.1.y e5cd595e23c1 eb2966c4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 possible deadlock in filename_create
* Struck through repros no longer work on HEAD.