Message-ID: <0000000000001b987605f47b72d3@google.com>
Date:   Sat, 11 Feb 2023 23:11:56 -0800
From:   syzbot <syzbot+5a195884ee3ad761db4e@...kaller.appspotmail.com>
To:     linux-kernel@...r.kernel.org, linux-unionfs@...r.kernel.org,
        miklos@...redi.hu, syzkaller-bugs@...glegroups.com
Subject: [syzbot] WARNING: locking bug in take_dentry_name_snapshot

Hello,

syzbot found the following issue on:

HEAD commit:    38d2b86a665b Add linux-next specific files for 20230208
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11f5e56b480000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3691b32dd4410e01
dashboard link: https://syzkaller.appspot.com/bug?extid=5a195884ee3ad761db4e
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, 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/0a9d60e90514/disk-38d2b86a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/71311be5f1a1/vmlinux-38d2b86a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a242870cc8eb/bzImage-38d2b86a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5a195884ee3ad761db4e@...kaller.appspotmail.com

reiserfs: enabling write barrier flush mode
REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage.
overlayfs: upper fs needs to support d_type.
overlayfs: upper fs does not support tmpfile.
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(1)
WARNING: CPU: 1 PID: 5500 at kernel/locking/lockdep.c:232 hlock_class kernel/locking/lockdep.c:232 [inline]
WARNING: CPU: 1 PID: 5500 at kernel/locking/lockdep.c:232 hlock_class kernel/locking/lockdep.c:221 [inline]
WARNING: CPU: 1 PID: 5500 at kernel/locking/lockdep.c:232 check_wait_context kernel/locking/lockdep.c:4746 [inline]
WARNING: CPU: 1 PID: 5500 at kernel/locking/lockdep.c:232 __lock_acquire+0x1664/0x5df0 kernel/locking/lockdep.c:5024
Modules linked in:
CPU: 1 PID: 5500 Comm: syz-executor.2 Not tainted 6.2.0-rc7-next-20230208-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:hlock_class kernel/locking/lockdep.c:232 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:221 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4746 [inline]
RIP: 0010:__lock_acquire+0x1664/0x5df0 kernel/locking/lockdep.c:5024
Code: 08 84 d2 0f 85 8c 3a 00 00 8b 0d 93 4e 10 0d 85 c9 0f 85 33 fb ff ff 48 c7 c6 80 6f 4c 8a 48 c7 c7 c0 63 4c 8a e8 9c 58 e6 ff <0f> 0b 31 ed e9 b3 ed ff ff e8 1e d6 b0 02 85 c0 0f 84 c3 fa ff ff
RSP: 0000:ffffc900059cf7f0 EFLAGS: 00010086
RAX: 0000000000000000 RBX: ffffffff92000c7f RCX: ffffc90005f61000
RDX: 0000000000040000 RSI: ffffffff814bfdd7 RDI: 0000000000000001
RBP: 0000000000001100 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 000000002d2d2d2d R12: ffff888028100ab0
R13: ffff888028100000 R14: 0000000000040000 R15: 0000000000041100
FS:  00007f8fab92e700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200de030 CR3: 00000000717c5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire.part.0+0x11c/0x370 kernel/locking/lockdep.c:5691
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:350 [inline]
 take_dentry_name_snapshot+0x2b/0x170 fs/dcache.c:315
 ovl_check_rename_whiteout fs/overlayfs/super.c:1207 [inline]
 ovl_make_workdir fs/overlayfs/super.c:1329 [inline]
 ovl_get_workdir fs/overlayfs/super.c:1444 [inline]
 ovl_fill_super+0x2090/0x7270 fs/overlayfs/super.c:2000
 mount_nodev+0x64/0x120 fs/super.c:1418
 legacy_get_tree+0x109/0x220 fs/fs_context.c:610
 vfs_get_tree+0x8d/0x350 fs/super.c:1502
 do_new_mount fs/namespace.c:3042 [inline]
 path_mount+0x1342/0x1e40 fs/namespace.c:3372
 do_mount fs/namespace.c:3385 [inline]
 __do_sys_mount fs/namespace.c:3594 [inline]
 __se_sys_mount fs/namespace.c:3571 [inline]
 __x64_sys_mount+0x283/0x300 fs/namespace.c:3571
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f8faac8c0f9
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:00007f8fab92e168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f8faadabf80 RCX: 00007f8faac8c0f9
RDX: 0000000020000080 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 00007f8faace7ae9 R08: 0000000020000480 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff1f6e324f R14: 00007f8fab92e300 R15: 0000000000022000
 </TASK>


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