[syzbot] [ext4?] WARNING: bad unlock balance in ext4_rename

[syzbot] [ext4?] WARNING: bad unlock balance in ext4_rename

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    9c1bec9c0b08 Merge tag 'linux-kselftest-fixes-6.3-rc3' of ..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12d6a556c80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6c84f77790aba2eb
dashboard link: https://syzkaller.appspot.com/bug?extid=636aeec054650b49a379
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/e27b04dd32d0/disk-9c1bec9c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7b5061fb1ef2/vmlinux-9c1bec9c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f36752323820/bzImage-9c1bec9c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+636aeec054650b49a379@syzkaller.appspotmail.com

ext4 filesystem being mounted at /root/syzkaller-testdir1527489572/syzkaller.Uw8Ert/4184/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs error (device loop4): ext4_get_first_dir_block:3520: inode #12: block 32: comm syz-executor.4: bad entry in directory: rec_len is smaller than minimal - offset=0, inode=67174412, rec_len=0, size=2048 fake=1
EXT4-fs error (device loop4): ext4_get_first_dir_block:3524: inode #12: comm syz-executor.4: directory missing '.'
=====================================
WARNING: bad unlock balance detected!
6.3.0-rc2-syzkaller-00050-g9c1bec9c0b08 #0 Not tainted
-------------------------------------
syz-executor.4/25678 is trying to release lock (&type->i_mutex_dir_key) at:
[<ffffffff8230b319>] inode_unlock include/linux/fs.h:763 [inline]
[<ffffffff8230b319>] ext4_rename+0x569/0x27c0 fs/ext4/namei.c:4029
but there are no more locks to release!

other info that might help us debug this:
2 locks held by syz-executor.4/25678:
 #0: ffff88807a162460 (sb_writers#4){.+.+}-{0:0}, at: do_renameat2+0x37f/0xc90 fs/namei.c:4859
 #1: ffff888084013628 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff888084013628 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: lock_rename+0x229/0x280 fs/namei.c:2991

stack backtrace:
CPU: 0 PID: 25678 Comm: syz-executor.4 Not tainted 6.3.0-rc2-syzkaller-00050-g9c1bec9c0b08 #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+0xd9/0x150 lib/dump_stack.c:106
 __lock_release kernel/locking/lockdep.c:5346 [inline]
 lock_release+0x4f1/0x670 kernel/locking/lockdep.c:5689
 up_write+0x2a/0x520 kernel/locking/rwsem.c:1625
 inode_unlock include/linux/fs.h:763 [inline]
 ext4_rename+0x569/0x27c0 fs/ext4/namei.c:4029
 ext4_rename2+0x1c7/0x270 fs/ext4/namei.c:4202
 vfs_rename+0xef6/0x17a0 fs/namei.c:4772
 do_renameat2+0xb62/0xc90 fs/namei.c:4923
 __do_sys_renameat2 fs/namei.c:4956 [inline]
 __se_sys_renameat2 fs/namei.c:4953 [inline]
 __x64_sys_renameat2+0xe8/0x120 fs/namei.c:4953
 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: 0033:0x7f762388c0f9
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:00007f7624588168 EFLAGS: 00000246 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007f76239abf80 RCX: 00007f762388c0f9
RDX: 0000000000000004 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 00007f76238e7b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000200 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd99195a8f R14: 00007f7624588300 R15: 0000000000022000
 </TASK>
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff8880870a0390, owner = 0x0, curr 0xffff88802506ba80, list empty
WARNING: CPU: 1 PID: 25678 at kernel/locking/rwsem.c:1369 __up_write kernel/locking/rwsem.c:1369 [inline]
WARNING: CPU: 1 PID: 25678 at kernel/locking/rwsem.c:1369 up_write+0x425/0x520 kernel/locking/rwsem.c:1626
Modules linked in:
CPU: 1 PID: 25678 Comm: syz-executor.4 Not tainted 6.3.0-rc2-syzkaller-00050-g9c1bec9c0b08 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:__up_write kernel/locking/rwsem.c:1369 [inline]
RIP: 0010:up_write+0x425/0x520 kernel/locking/rwsem.c:1626
Code: 3c 02 00 0f 85 da 00 00 00 48 8b 55 00 4d 89 f1 53 4d 89 f8 4c 89 e9 48 c7 c6 60 51 4c 8a 48 c7 c7 00 50 4c 8a e8 7b 1b e8 ff <0f> 0b 59 e9 dd fc ff ff 48 89 df e8 eb aa 70 00 e9 1a fc ff ff 48
RSP: 0018:ffffc9000319f9a0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff8a4c4f40 RCX: ffffc9000c5aa000
RDX: 0000000000040000 RSI: ffffffff814b6037 RDI: 0000000000000001
RBP: ffff8880870a0390 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 57525f4755424544 R12: ffff8880870a0398
R13: ffff8880870a0390 R14: ffff88802506ba80 R15: 0000000000000000
FS:  00007f7624588700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020526000 CR3: 000000001cfeb000 CR4: 0000000000350ee0
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:763 [inline]
 ext4_rename+0x569/0x27c0 fs/ext4/namei.c:4029
 ext4_rename2+0x1c7/0x270 fs/ext4/namei.c:4202
 vfs_rename+0xef6/0x17a0 fs/namei.c:4772
 do_renameat2+0xb62/0xc90 fs/namei.c:4923
 __do_sys_renameat2 fs/namei.c:4956 [inline]
 __se_sys_renameat2 fs/namei.c:4953 [inline]
 __x64_sys_renameat2+0xe8/0x120 fs/namei.c:4953
 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: 0033:0x7f762388c0f9
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:00007f7624588168 EFLAGS: 00000246 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007f76239abf80 RCX: 00007f762388c0f9
RDX: 0000000000000004 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 00007f76238e7b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000200 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd99195a8f R14: 00007f7624588300 R15: 0000000000022000
 </TASK>


---
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Re: [syzbot] [ext4?] WARNING: bad unlock balance in ext4_rename

[Theodore Ts'o]

On Thu, Mar 16, 2023 at 03:51:50AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    9c1bec9c0b08 Merge tag 'linux-kselftest-fixes-6.3-rc3' of ..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12d6a556c80000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6c84f77790aba2eb
> dashboard link: https://syzkaller.appspot.com/bug?extid=636aeec054650b49a379
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> 

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.5-rc2

Re: [syzbot] [ext4?] WARNING: bad unlock balance in ext4_rename

[syzbot]

> On Thu, Mar 16, 2023 at 03:51:50AM -0700, syzbot wrote:
>> Hello,
>> 
>> syzbot found the following issue on:
>> 
>> HEAD commit:    9c1bec9c0b08 Merge tag 'linux-kselftest-fixes-6.3-rc3' of ..
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=12d6a556c80000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=6c84f77790aba2eb
>> dashboard link: https://syzkaller.appspot.com/bug?extid=636aeec054650b49a379
>> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>> 
>
> #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.5-rc2

This crash does not have a reproducer. I cannot test it.

>