[syzbot] possible deadlock in mnt_want_write_file

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f2f32f8af2b0 Merge tag 'for-6.1-rc3-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=164d52ca880000
kernel config: https://syzkaller.appspot.com/x/.config?x=f7e100ed8aaa828e
dashboard link: https://syzkaller.appspot.com/bug?extid=1047e42179f502f2b0a2
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, 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/ea126f52b953/disk-f2f32f8a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/815b36048854/vmlinux-f2f32f8a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b7d04bb936fd/bzImage-f2f32f8a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1047e4...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc3-syzkaller-00152-gf2f32f8af2b0 #0 Not tainted
------------------------------------------------------
syz-executor.3/17174 is trying to acquire lock:
ffff88807eba6460 (sb_writers#30){.+.+}-{0:0}, at: mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437

but task is already holding lock:
ffff88804aba9090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x77/0xd0 fs/reiserfs/lock.c:27

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sbi->lock){+.+.}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
reiserfs_write_lock+0x77/0xd0 fs/reiserfs/lock.c:27
reiserfs_lookup+0x147/0x490 fs/reiserfs/namei.c:364
__lookup_hash+0x115/0x240 fs/namei.c:1601
filename_create+0x25f/0x4f0 fs/namei.c:3807
do_mkdirat+0xb5/0x550 fs/namei.c:4050
__do_sys_mkdirat fs/namei.c:4075 [inline]
__se_sys_mkdirat fs/namei.c:4073 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4073
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&type->i_mutex_dir_key#21/1){+.+.}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
down_write_nested+0xa2/0x280 kernel/locking/rwsem.c:1672
inode_lock_nested include/linux/fs.h:791 [inline]
filename_create+0x22a/0x4f0 fs/namei.c:3806
do_mkdirat+0xb5/0x550 fs/namei.c:4050
__do_sys_mkdirat fs/namei.c:4075 [inline]
__se_sys_mkdirat fs/namei.c:4073 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4073
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sb_writers#30){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1826 [inline]
sb_start_write+0x4d/0x1a0 include/linux/fs.h:1901
mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
reiserfs_ioctl+0x16e/0x340 fs/reiserfs/ioctl.c:103
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
sb_writers#30 --> &type->i_mutex_dir_key#21/1 --> &sbi->lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&sbi->lock);
lock(&type->i_mutex_dir_key#21/1);
lock(&sbi->lock);
lock(sb_writers#30);

*** DEADLOCK ***

1 lock held by syz-executor.3/17174:
#0: ffff88804aba9090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x77/0xd0 fs/reiserfs/lock.c:27

stack backtrace:
CPU: 0 PID: 17174 Comm: syz-executor.3 Not tainted 6.1.0-rc3-syzkaller-00152-gf2f32f8af2b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1826 [inline]
sb_start_write+0x4d/0x1a0 include/linux/fs.h:1901
mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
reiserfs_ioctl+0x16e/0x340 fs/reiserfs/ioctl.c:103
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f7f6ee8b5a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7f6e1de168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7f6efac050 RCX: 00007f7f6ee8b5a9
RDX: 0000000020000080 RSI: 0000000040087602 RDI: 0000000000000007
RBP: 00007f7f6eee67b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdcec8c8df R14: 00007f7f6e1de300 R15: 0000000000022000
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: eb7081409f94 Linux 6.1-rc6
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=155d6d45880000
kernel config: https://syzkaller.appspot.com/x/.config?x=8cdf448d3b35234

dashboard link: https://syzkaller.appspot.com/bug?extid=1047e42179f502f2b0a2
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1167648d880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1562d6c5880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4a019f55c517/disk-eb708140.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eb36e890aa8b/vmlinux-eb708140.xz
kernel image: https://storage.googleapis.com/syzbot-assets/feee2c23ec64/bzImage-eb708140.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/aa387a5f9eda/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1047e4...@syzkaller.appspotmail.com

REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.

======================================================
WARNING: possible circular locking dependency detected

6.1.0-rc6-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor139/3633 is trying to acquire lock:
ffff888026b18460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437

but task is already holding lock:

ffff88801f89c090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x77/0xd0 fs/reiserfs/lock.c:27

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&sbi->lock){+.+.}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
reiserfs_write_lock+0x77/0xd0 fs/reiserfs/lock.c:27
reiserfs_lookup+0x147/0x490 fs/reiserfs/namei.c:364

__lookup_slow+0x266/0x3a0 fs/namei.c:1685
lookup_one_len+0x430/0x690 fs/namei.c:2711
reiserfs_lookup_privroot+0x85/0x1e0 fs/reiserfs/xattr.c:973
reiserfs_fill_super+0x2071/0x24a0 fs/reiserfs/super.c:2174
mount_bdev+0x26c/0x3a0 fs/super.c:1401
legacy_get_tree+0xea/0x180 fs/fs_context.c:610
vfs_get_tree+0x88/0x270 fs/super.c:1531
do_new_mount+0x289/0xad0 fs/namespace.c:3040
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&type->i_mutex_dir_key#6){+.+.}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
down_write+0x9c/0x270 kernel/locking/rwsem.c:1562
inode_lock include/linux/fs.h:756 [inline]
open_last_lookups fs/namei.c:3478 [inline]
path_openat+0x7b9/0x2df0 fs/namei.c:3710
do_filp_open+0x264/0x4f0 fs/namei.c:3740
do_sys_openat2+0x124/0x4e0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1396

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sb_writers#9){.+.+}-{0:0}:

check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1826 [inline]
sb_start_write+0x4d/0x1a0 include/linux/fs.h:1901
mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
reiserfs_ioctl+0x16e/0x340 fs/reiserfs/ioctl.c:103
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:

sb_writers#9 --> &type->i_mutex_dir_key#6 --> &sbi->lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&sbi->lock);

lock(&type->i_mutex_dir_key#6);
lock(&sbi->lock);
lock(sb_writers#9);

*** DEADLOCK ***

1 lock held by syz-executor139/3633:
#0: ffff88801f89c090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x77/0xd0 fs/reiserfs/lock.c:27

stack backtrace:
CPU: 1 PID: 3633 Comm: syz-executor139 Not tainted 6.1.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022

Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1826 [inline]
sb_start_write+0x4d/0x1a0 include/linux/fs.h:1901
mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
reiserfs_ioctl+0x16e/0x340 fs/reiserfs/ioctl.c:103
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f9c2c672829
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffffe9d1ea8 EFLAGS:

[Hillf Danton]

On 22 Nov 2022 18:33:39 -0800

> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: eb7081409f94 Linux 6.1-rc6
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1562d6c5880000

Fix the deadlock by reversing the order of lock(&sbi->lock) and lock(sb_writers#9).

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git eb7081409f94

--- x/fs/reiserfs/ioctl.c
+++ y/fs/reiserfs/ioctl.c
@@ -78,6 +78,9 @@ long reiserfs_ioctl(struct file *filp, u
struct inode *inode = file_inode(filp);
int err = 0;

+ err = mnt_want_write_file(filp);
+ if (err)
+ return err;
reiserfs_write_lock(inode->i_sb);

switch (cmd) {
@@ -100,23 +103,19 @@ long reiserfs_ioctl(struct file *filp, u
err = -EPERM;
break;
}
- err = mnt_want_write_file(filp);
- if (err)
- break;
if (get_user(inode->i_generation, (int __user *)arg)) {
err = -EFAULT;
- goto setversion_out;
+ break;
}
inode->i_ctime = current_time(inode);
mark_inode_dirty(inode);
-setversion_out:
- mnt_drop_write_file(filp);
break;
default:
err = -ENOTTY;
}

reiserfs_write_unlock(inode->i_sb);
+ mnt_drop_write_file(filp);

return err;
}
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel BUG in do_journal_begin_r

REISERFS (device loop0): journal params: device loop0, size 512, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)

REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.

------------[ cut here ]------------
kernel BUG at fs/reiserfs/journal.c:3039!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5794 Comm: syz-executor.0 Not tainted 6.1.0-rc6-syzkaller-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022

RIP: 0010:do_journal_begin_r+0x105b/0x1070 fs/reiserfs/journal.c:3039
Code: ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 22 ff ff ff 48 89 df e8 a6 eb b2 ff e9 15 ff ff ff e8 bc d3 5e ff 0f 0b e8 b5 d3 5e ff <0f> 0b e8 2e 6f 6a 08 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 55
RSP: 0018:ffffc900095cf5e0 EFLAGS: 00010293
RAX: ffffffff822bc4bb RBX: 000000001100e5be RCX: ffff88807d299d40
RDX: 0000000000000000 RSI: 000000001100e5be RDI: 0000000000000100
RBP: ffffc900095cf788 R08: ffffffff822bb592 R09: fffffbfff1d2f2de
R10: fffffbfff1d2f2de R11: 1ffffffff1d2f2dd R12: ffff88807a6c6678
R13: ffffc9000ac11214 R14: dffffc0000000000 R15: 0000000000000100
FS: 00007fd0ac76a700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd0abba8000 CR3: 000000007980d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
journal_begin+0x14b/0x350 fs/reiserfs/journal.c:3255
reiserfs_create+0x2c3/0x660 fs/reiserfs/namei.c:661
lookup_open fs/namei.c:3413 [inline]
open_last_lookups fs/namei.c:3481 [inline]
path_openat+0x12d0/0x2df0 fs/namei.c:3710

do_filp_open+0x264/0x4f0 fs/namei.c:3740
do_sys_openat2+0x124/0x4e0 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__x64_sys_creat+0x11f/0x160 fs/open.c:1396
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7fd0aba8c189
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd0ac76a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fd0abbabf80 RCX: 00007fd0aba8c189
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000040
RBP: 00007fd0abae7b01 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007ffeb4434c9f R14: 00007fd0ac76a300 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:do_journal_begin_r+0x105b/0x1070 fs/reiserfs/journal.c:3039
Code: ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 22 ff ff ff 48 89 df e8 a6 eb b2 ff e9 15 ff ff ff e8 bc d3 5e ff 0f 0b e8 b5 d3 5e ff <0f> 0b e8 2e 6f 6a 08 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 55
RSP: 0018:ffffc900095cf5e0 EFLAGS: 00010293
RAX: ffffffff822bc4bb RBX: 000000001100e5be RCX: ffff88807d299d40
RDX: 0000000000000000 RSI: 000000001100e5be RDI: 0000000000000100
RBP: ffffc900095cf788 R08: ffffffff822bb592 R09: fffffbfff1d2f2de
R10: fffffbfff1d2f2de R11: 1ffffffff1d2f2dd R12: ffff88807a6c6678
R13: ffffc9000ac11214 R14: dffffc0000000000 R15: 0000000000000100
FS: 00007fd0ac76a700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd0abba8000 CR3: 000000007980d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit: eb708140 Linux 6.1-rc6
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=14428075880000

kernel config: https://syzkaller.appspot.com/x/.config?x=8cdf448d3b35234
dashboard link: https://syzkaller.appspot.com/bug?extid=1047e42179f502f2b0a2
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=153b4afd880000

[Hillf Danton]

On 22 Nov 2022 18:33:39 -0800

> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: eb7081409f94 Linux 6.1-rc6
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1562d6c5880000

Fix the deadlock by reversing the order of lock(&sbi->lock) and lock(sb_writers#9).

Add debug info.

--- x/fs/reiserfs/namei.c
+++ y/fs/reiserfs/namei.c
@@ -658,6 +658,12 @@ static int reiserfs_create(struct user_n
jbegin_count += retval;
reiserfs_write_lock(dir->i_sb);

+ if (WARN_ON_ONCE(jbegin_count > SB_JOURNAL(dir->i_sb)->j_trans_max,
+ "%s() jbegin_count %d > SB_JOURNAL(dir->i_sb)->j_trans_max %u\n",
+ __func__, jbegin_count, SB_JOURNAL(dir->i_sb)->j_trans_max)) {
+ retval = -EINVAL;
+ goto out_failed;
+ }
retval = journal_begin(&th, dir->i_sb, jbegin_count);
if (retval) {
drop_new_inode(inode);
--

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

fs/reiserfs/namei.c:662:4: error: too many arguments provided to function-like macro invocation
fs/reiserfs/namei.c:661:6: error: use of undeclared identifier 'WARN_ON_ONCE'

Tested on:

commit: eb708140 Linux 6.1-rc6
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

dashboard link: https://syzkaller.appspot.com/bug?extid=1047e42179f502f2b0a2
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=1239542d880000

[Hillf Danton]

On 22 Nov 2022 18:33:39 -0800

> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: eb7081409f94 Linux 6.1-rc6
> git tree: upstream

+ if (WARN_ONCE(jbegin_count > SB_JOURNAL(dir->i_sb)->j_trans_max,

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+1047e4...@syzkaller.appspotmail.com

Tested on:

commit: eb708140 Linux 6.1-rc6
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

console output: https://syzkaller.appspot.com/x/log.txt?x=12589ac3880000
kernel config: https://syzkaller.appspot.com/x/.config?x=8cdf448d3b35234

dashboard link: https://syzkaller.appspot.com/bug?extid=1047e42179f502f2b0a2
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=17711155880000

Note: testing is done by a robot and is best-effort only.

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 6f861765464f43a71462d52026fbddfc858239a5
Author: Jan Kara <ja...@suse.cz>
Date: Wed Nov 1 17:43:10 2023 +0000

fs: Block writes to mounted block devices

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=164f208e180000
start commit: ac865f00af29 Merge tag 'pci-v6.7-fixes-2' of git://git.ker..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=655f8abe9fe69b3b
dashboard link: https://syzkaller.appspot.com/bug?extid=1047e42179f502f2b0a2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=116d8055e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15687d81e80000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fs: Block writes to mounted block devices

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.