syzbot


possible deadlock in iterate_dir

Status: upstream: reported on 2022/12/24 12:14
Subsystems: reiserfs (incorrect?)
Reported-by: syzbot+435320768a3c52aa94b6@syzkaller.appspotmail.com
First crash: 92d, last: 5d23h
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 possible deadlock in iterate_dir ubifs C 11375 15d 1010d 0/1 upstream: reported C repro on 2020/06/15 06:16
linux-4.19 possible deadlock in iterate_dir 1 1182d 1182d 0/1 auto-closed as invalid on 2020/04/24 15:06

Sample crash report:
REISERFS (device loop3): Using r5 hash to sort names
reiserfs: enabling write barrier flush mode
REISERFS warning (device loop3): jdm-20006 create_privroot: xattrs/ACLs enabled and couldn't find/create .reiserfs_priv. Failing mount.
======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc2-syzkaller-00069-g0ddc84d2dd43 #0 Not tainted
------------------------------------------------------
syz-executor.3/4566 is trying to acquire lock:
ffff88802bc36090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7a/0xd0 fs/reiserfs/lock.c:27

but task is already holding lock:
ffff88802b846460 (sb_writers#42){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2181 [inline]
ffff88802b846460 (sb_writers#42){.+.+}-{0:0}, at: iterate_dir+0x488/0x570 fs/readdir.c:70

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#42){.+.+}-{0:0}:
       lock_acquire+0x1e1/0x520 kernel/locking/lockdep.c:5669
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1477 [inline]
       sb_start_write+0x4d/0x1c0 include/linux/fs.h:1552
       mnt_want_write_file+0x5e/0x1f0 fs/namespace.c:438
       reiserfs_ioctl+0x174/0x340 fs/reiserfs/ioctl.c:103
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:870 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&sbi->lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain+0x166b/0x58e0 kernel/locking/lockdep.c:3832
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
       lock_acquire+0x1e1/0x520 kernel/locking/lockdep.c:5669
       __mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
       reiserfs_write_lock+0x7a/0xd0 fs/reiserfs/lock.c:27
       reiserfs_dirty_inode+0xf2/0x240 fs/reiserfs/super.c:704
       __mark_inode_dirty+0x305/0xd90 fs/fs-writeback.c:2421
       generic_update_time fs/inode.c:1860 [inline]
       inode_update_time fs/inode.c:1873 [inline]
       touch_atime+0x3fe/0x680 fs/inode.c:1945
       file_accessed include/linux/fs.h:2181 [inline]
       iterate_dir+0x488/0x570 fs/readdir.c:70
       __do_sys_getdents fs/readdir.c:286 [inline]
       __se_sys_getdents+0x1ef/0x4c0 fs/readdir.c:271
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#42);
                               lock(&sbi->lock);
                               lock(sb_writers#42);
  lock(&sbi->lock);

 *** DEADLOCK ***

3 locks held by syz-executor.3/4566:
 #0: ffff8880214fc5e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x254/0x2f0 fs/file.c:1047
 #1: ffff888043bd7a20 (&type->i_mutex_dir_key#25){++++}-{3:3}, at: iterate_dir+0x10e/0x570 fs/readdir.c:55
 #2: ffff88802b846460 (sb_writers#42){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2181 [inline]
 #2: ffff88802b846460 (sb_writers#42){.+.+}-{0:0}, at: iterate_dir+0x488/0x570 fs/readdir.c:70

stack backtrace:
CPU: 1 PID: 4566 Comm: syz-executor.3 Not tainted 6.3.0-rc2-syzkaller-00069-g0ddc84d2dd43 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2fe/0x3b0 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain+0x166b/0x58e0 kernel/locking/lockdep.c:3832
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
 lock_acquire+0x1e1/0x520 kernel/locking/lockdep.c:5669
 __mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
 reiserfs_write_lock+0x7a/0xd0 fs/reiserfs/lock.c:27
 reiserfs_dirty_inode+0xf2/0x240 fs/reiserfs/super.c:704
 __mark_inode_dirty+0x305/0xd90 fs/fs-writeback.c:2421
 generic_update_time fs/inode.c:1860 [inline]
 inode_update_time fs/inode.c:1873 [inline]
 touch_atime+0x3fe/0x680 fs/inode.c:1945
 file_accessed include/linux/fs.h:2181 [inline]
 iterate_dir+0x488/0x570 fs/readdir.c:70
 __do_sys_getdents fs/readdir.c:286 [inline]
 __se_sys_getdents+0x1ef/0x4c0 fs/readdir.c:271
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb605e8c0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007fb606c46168 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007fb605fabf80 RCX: 00007fb605e8c0f9
RDX: 0000000000000ffa RSI: 00000000200003c0 RDI: 0000000000000005
RBP: 00007fb605ee7b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeddeff79f R14: 00007fb606c46300 R15: 0000000000022000
 </TASK>

Crashes (8):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-upstream-fs 2023/03/16 20:23 upstream 0ddc84d2dd43 18b58603 .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
ci2-upstream-fs 2023/03/16 20:07 upstream 0ddc84d2dd43 18b58603 .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
ci2-upstream-fs 2023/03/15 23:16 upstream 9c1bec9c0b08 18b58603 .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
ci2-upstream-fs 2023/03/02 20:19 upstream 04a357b1f6f0 f8902b57 .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
ci2-upstream-fs 2023/02/21 21:05 upstream 9e58df973d22 42a4d508 .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
ci2-upstream-fs 2023/02/20 22:15 upstream 91bc559d8d3a 2414209c .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
ci2-upstream-fs 2023/02/17 16:49 upstream ec35307e18ba cf8c2d39 .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
ci-upstream-kasan-gce-root 2022/12/20 12:08 upstream 6feb57c2fd7c d3e76707 .config console log report info [disk image] [vmlinux] [kernel image] possible deadlock in iterate_dir
* Struck through repros no longer work on HEAD.