From: syzbot <syzbot+c73ff6790f3d6c635abc@syzkaller.appspotmail.com>
To: heming.zhao@suse.com, jlbec@evilplan.org,
joseph.qi@linux.alibaba.com, linux-kernel@vger.kernel.org,
mark@fasheh.com, ocfs2-devel@lists.linux.dev,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [ocfs2?] possible deadlock in vfs_rename (3)
Date: Mon, 19 Oct 2026 17:11:07 -0700 [thread overview]
Message-ID: <6ad6b19b.b5bd089a.6b57.0081.GAE@google.com> (raw)
In-Reply-To: <6ab41b7d.e548f532.1ca396.0020.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: c03c1a14507d Linux 7.3
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14a519cd580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c4b098695335c89f
dashboard link: https://syzkaller.appspot.com/bug?extid=c73ff6790f3d6c635abc
compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12a519cd580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=137cc831580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c9d4a36731a6/disk-c03c1a14.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3c00e4e185bb/vmlinux-c03c1a14.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1f95d3156291/bzImage-c03c1a14.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2e6531d7c325/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=15381831580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c73ff6790f3d6c635abc@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor105/5623 is trying to acquire lock:
ffff8880767009a0 (&sb->s_type->i_mutex_key#18){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
ffff8880767009a0 (&sb->s_type->i_mutex_key#18){+.+.}-{4:4}, at: vfs_rename+0x6e3/0xef0 fs/namei.c:-1
but task is already holding lock:
ffff8880764ff9a0 (&sb->s_type->i_mutex_key#18/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline]
ffff8880764ff9a0 (&sb->s_type->i_mutex_key#18/2){+.+.}-{4:4}, at: vfs_rename+0x64d/0xef0 fs/namei.c:6159
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&sb->s_type->i_mutex_key#18/2){+.+.}-{4:4}:
down_write_nested+0x9d/0x210 kernel/locking/rwsem.c:1757
inode_lock_nested include/linux/fs.h:1069 [inline]
__ocfs2_reflink+0xcab/0x16e0 fs/ocfs2/refcounttree.c:4198
ocfs2_reflink+0x4eb/0x920 fs/ocfs2/refcounttree.c:4297
ocfs2_vfs_reflink+0x338/0x450 fs/ocfs2/refcounttree.c:4423
ocfs2_reflink_ioctl+0x3a0/0x450 fs/ocfs2/refcounttree.c:4463
ocfs2_ioctl+0x5b5/0x7e0 fs/ocfs2/ioctl.c:920
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&oi->ip_alloc_sem){+.+.}-{4:4}:
down_write+0x96/0x200 kernel/locking/rwsem.c:1631
ocfs2_reflink+0x4d2/0x920 fs/ocfs2/refcounttree.c:4296
ocfs2_vfs_reflink+0x338/0x450 fs/ocfs2/refcounttree.c:4423
ocfs2_reflink_ioctl+0x3a0/0x450 fs/ocfs2/refcounttree.c:4463
ocfs2_ioctl+0x5b5/0x7e0 fs/ocfs2/ioctl.c:920
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&oi->ip_xattr_sem){++++}-{4:4}:
down_write+0x96/0x200 kernel/locking/rwsem.c:1631
ocfs2_reflink+0x4c3/0x920 fs/ocfs2/refcounttree.c:4295
ocfs2_vfs_reflink+0x338/0x450 fs/ocfs2/refcounttree.c:4423
ocfs2_reflink_ioctl+0x3a0/0x450 fs/ocfs2/refcounttree.c:4463
ocfs2_ioctl+0x5b5/0x7e0 fs/ocfs2/ioctl.c:920
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#18){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3209 [inline]
check_prevs_add kernel/locking/lockdep.c:3328 [inline]
validate_chain kernel/locking/lockdep.c:3952 [inline]
__lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
down_write+0x96/0x200 kernel/locking/rwsem.c:1631
inode_lock include/linux/fs.h:1024 [inline]
vfs_rename+0x6e3/0xef0 fs/namei.c:-1
filename_renameat2+0x533/0x9a0 fs/namei.c:6325
__do_sys_rename fs/namei.c:6369 [inline]
__se_sys_rename+0x55/0x2c0 fs/namei.c:6365
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&sb->s_type->i_mutex_key#18 --> &oi->ip_alloc_sem --> &sb->s_type->i_mutex_key#18/2
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sb->s_type->i_mutex_key#18/2);
lock(&oi->ip_alloc_sem);
lock(&sb->s_type->i_mutex_key#18/2);
lock(&sb->s_type->i_mutex_key#18);
*** DEADLOCK ***
locks held by syz-executor105/5623: 5, last CPU#1:
#0: ffff88807f244460 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:531
#1: ffff88807f244768 (&type->s_vfs_rename_key){+.+.}-{4:4}, at: lock_rename fs/namei.c:3789 [inline]
#1: ffff88807f244768 (&type->s_vfs_rename_key){+.+.}-{4:4}, at: __start_renaming+0xed/0x410 fs/namei.c:3878
#2: ffff8880767025a0 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline]
#2: ffff8880767025a0 (&type->i_mutex_dir_key#6/1){+.+.}-{4:4}, at: lock_two_directories+0x141/0x220 fs/namei.c:3755
#3: ffff8880767017a0 (&sb->s_type->i_mutex_key#18/5){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline]
#3: ffff8880767017a0 (&sb->s_type->i_mutex_key#18/5){+.+.}-{4:4}, at: lock_two_directories+0x16b/0x220 fs/namei.c:3756
#4: ffff8880764ff9a0 (&sb->s_type->i_mutex_key#18/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline]
#4: ffff8880764ff9a0 (&sb->s_type->i_mutex_key#18/2){+.+.}-{4:4}, at: vfs_rename+0x64d/0xef0 fs/namei.c:6159
stack backtrace:
CPU: 1 UID: 0 PID: 5623 Comm: syz-executor105 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087
check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219
check_prev_add kernel/locking/lockdep.c:3209 [inline]
check_prevs_add kernel/locking/lockdep.c:3328 [inline]
validate_chain kernel/locking/lockdep.c:3952 [inline]
__lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
down_write+0x96/0x200 kernel/locking/rwsem.c:1631
inode_lock include/linux/fs.h:1024 [inline]
vfs_rename+0x6e3/0xef0 fs/namei.c:-1
filename_renameat2+0x533/0x9a0 fs/namei.c:6325
__do_sys_rename fs/namei.c:6369 [inline]
__se_sys_rename+0x55/0x2c0 fs/namei.c:6365
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5228311de9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd98464798 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5228311de9
RDX: 69662f7375622f2e RSI: 0000200000002bc0 RDI: 0000200000002b80
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffd984647d0
R10: 00007ffd984647a0 R11: 0000000000000246 R12: 00007ffd984647d0
R13: 0000000000000002 R14: 431bde82d7b634db R15: 00007f522837104b
</TASK>
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
prev parent reply other threads:[~2026-10-20 0:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-23 18:33 syzbot
2026-10-20 0:11 ` syzbot [this message]
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