All of lore.kernel.org
 help / color / mirror / Atom feed
From: syzbot <syzbot+dc5bf13993c4b32ec0cb@syzkaller.appspotmail.com>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	reiserfs-devel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [reiserfs?] possible deadlock in chmod_common
Date: Sun, 23 Apr 2023 23:46:46 -0700	[thread overview]
Message-ID: <000000000000df076505fa0f5e84@google.com> (raw)

Hello,

syzbot found the following issue on:

HEAD commit:    2caeeb9d4a1b Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=109cffafc80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4afb87f3ec27b7fd
dashboard link: https://syzkaller.appspot.com/bug?extid=dc5bf13993c4b32ec0cb
compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/187205513d6f/disk-2caeeb9d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ae84a1e0cbd0/vmlinux-2caeeb9d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0f0ff6d2e1aa/bzImage-2caeeb9d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dc5bf13993c4b32ec0cb@syzkaller.appspotmail.com

REISERFS warning (device loop2): 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-rc7-syzkaller-00189-g2caeeb9d4a1b #0 Not tainted
------------------------------------------------------
syz-executor.2/13499 is trying to acquire lock:
ffff88803a019020 (&type->i_mutex_dir_key#25){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff88803a019020 (&type->i_mutex_dir_key#25){+.+.}-{3:3}, at: chmod_common+0x1bb/0x4c0 fs/open.c:637

but task is already holding lock:
ffff8880281c2460 (sb_writers#30){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:394

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (sb_writers#30){.+.+}-{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

-> #1 (&sbi->lock){+.+.}-{3:3}:
       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_lookup+0x160/0x4b0 fs/reiserfs/namei.c:364
       __lookup_slow+0x282/0x3e0 fs/namei.c:1686
       lookup_one_len+0x18b/0x2d0 fs/namei.c:2712
       reiserfs_lookup_privroot+0x89/0x1e0 fs/reiserfs/xattr.c:973
       reiserfs_fill_super+0x195b/0x2620 fs/reiserfs/super.c:2192
       mount_bdev+0x271/0x3a0 fs/super.c:1380
       legacy_get_tree+0xef/0x190 fs/fs_context.c:610
       vfs_get_tree+0x8c/0x270 fs/super.c:1510
       do_new_mount+0x28f/0xae0 fs/namespace.c:3042
       do_mount fs/namespace.c:3385 [inline]
       __do_sys_mount fs/namespace.c:3594 [inline]
       __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3571
       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 (&type->i_mutex_dir_key#25){+.+.}-{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
       down_write+0x3a/0x50 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       chmod_common+0x1bb/0x4c0 fs/open.c:637
       vfs_fchmod fs/open.c:659 [inline]
       __do_sys_fchmod fs/open.c:668 [inline]
       __se_sys_fchmod fs/open.c:662 [inline]
       __x64_sys_fchmod+0xf0/0x150 fs/open.c:662
       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:

Chain exists of:
  &type->i_mutex_dir_key#25 --> &sbi->lock --> sb_writers#30

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#30);
                               lock(&sbi->lock);
                               lock(sb_writers#30);
  lock(&type->i_mutex_dir_key#25);

 *** DEADLOCK ***

1 lock held by syz-executor.2/13499:
 #0: ffff8880281c2460 (sb_writers#30){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:394

stack backtrace:
CPU: 0 PID: 13499 Comm: syz-executor.2 Not tainted 6.3.0-rc7-syzkaller-00189-g2caeeb9d4a1b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
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
 down_write+0x3a/0x50 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:758 [inline]
 chmod_common+0x1bb/0x4c0 fs/open.c:637
 vfs_fchmod fs/open.c:659 [inline]
 __do_sys_fchmod fs/open.c:668 [inline]
 __se_sys_fchmod fs/open.c:662 [inline]
 __x64_sys_fchmod+0xf0/0x150 fs/open.c:662
 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: 0033:0x7f94a988c169
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:00007f94aa5e0168 EFLAGS: 00000246 ORIG_RAX: 000000000000005b
RAX: ffffffffffffffda RBX: 00007f94a99abf80 RCX: 00007f94a988c169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f94a98e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe4c3619af R14: 00007f94aa5e0300 R15: 0000000000022000
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

                 reply	other threads:[~2023-04-24  6:46 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=000000000000df076505fa0f5e84@google.com \
    --to=syzbot+dc5bf13993c4b32ec0cb@syzkaller.appspotmail.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=reiserfs-devel@vger.kernel.org \
    --cc=syzkaller-bugs@googlegroups.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.