* WARNING: locking bug in loop_control_ioctl
@ 2018-11-09 19:48 syzbot
2018-11-10 8:09 ` Tetsuo Handa
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2018-11-09 19:48 UTC (permalink / raw)
To: axboe, linux-block, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following crash on:
HEAD commit: 442b8cea2477 Add linux-next specific files for 20181109
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14790f7b400000
kernel config: https://syzkaller.appspot.com/x/.config?x=66046c6bfaf1f24d
dashboard link: https://syzkaller.appspot.com/bug?extid=c0138741c2290fc5e63f
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15ef394d400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=111cfb83400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(depth <= 0)
WARNING: CPU: 1 PID: 5795 at kernel/locking/lockdep.c:3595 __lock_release
kernel/locking/lockdep.c:3595 [inline]
WARNING: CPU: 1 PID: 5795 at kernel/locking/lockdep.c:3595
lock_release+0x740/0xa10 kernel/locking/lockdep.c:3863
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 5795 Comm: syz-executor569 Not tainted
4.20.0-rc1-next-20181109+ #109
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
panic+0x2ad/0x55c kernel/panic.c:188
__warn.cold.8+0x20/0x45 kernel/panic.c:540
report_bug+0x254/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:__lock_release kernel/locking/lockdep.c:3595 [inline]
RIP: 0010:lock_release+0x740/0xa10 kernel/locking/lockdep.c:3863
Code: 03 38 d0 7c 08 84 d2 0f 85 da 02 00 00 8b 35 a7 82 b3 08 85 f6 75 15
48 c7 c6 20 66 2b 88 48 c7 c7 c0 33 2b 88 e8 10 36 e7 ff <0f> 0b 48 8b 95
e8 fe ff ff 4c 89 f7 48 8b b5 f0 fe ff ff e8 e8 58
RSP: 0018:ffff8801b9867868 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 1ffff1003730cf12 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8165ba15 RDI: 0000000000000006
RBP: ffff8801b9867998 R08: ffff8801d24940c0 R09: fffffbfff12b2254
R10: fffffbfff12b2254 R11: ffffffff895912a3 R12: ffffffff8b0e17a0
R13: ffff8801b9867970 R14: ffff8801d24940c0 R15: ffff8801b98678b0
__mutex_unlock_slowpath+0x102/0x8c0 kernel/locking/mutex.c:1197
mutex_unlock+0xd/0x10 kernel/locking/mutex.c:713
loop_control_ioctl+0xf5/0x4e0 drivers/block/loop.c:2095
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x447009
Code: e8 0c b4 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fba6d10bda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006e19e8 RCX: 0000000000447009
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 00000000006e19e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e19ec
R13: 6f72746e6f632d70 R14: 6f6f6c2f7665642f R15: 00000000006e19e0
Kernel Offset: disabled
Rebooting in 86400 seconds..
---
This bug 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 bug report. See:
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syzbot can test patches for this bug, for details see:
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: WARNING: locking bug in loop_control_ioctl
2018-11-09 19:48 WARNING: locking bug in loop_control_ioctl syzbot
@ 2018-11-10 8:09 ` Tetsuo Handa
2018-11-12 2:56 ` Ming Lei
2018-11-12 11:02 ` Jan Kara
0 siblings, 2 replies; 4+ messages in thread
From: Tetsuo Handa @ 2018-11-10 8:09 UTC (permalink / raw)
To: axboe, Jan Kara; +Cc: syzbot, linux-block, linux-kernel, syzkaller-bugs
From 4b9e5556fada37dff1eff13665a229b69e1f7dd8 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Sat, 10 Nov 2018 17:04:40 +0900
Subject: [PATCH] loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl().
Commit 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") forgot to
remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when
replacing loop_index_mutex with loop_ctl_mutex.
Reported-by: syzbot <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Jan Kara <jack@suse.cz>
---
drivers/block/loop.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index bf6bc35..176ab1f 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2074,12 +2074,10 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
break;
if (lo->lo_state != Lo_unbound) {
ret = -EBUSY;
- mutex_unlock(&loop_ctl_mutex);
break;
}
if (atomic_read(&lo->lo_refcnt) > 0) {
ret = -EBUSY;
- mutex_unlock(&loop_ctl_mutex);
break;
}
lo->lo_disk->private_data = NULL;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: WARNING: locking bug in loop_control_ioctl
2018-11-10 8:09 ` Tetsuo Handa
@ 2018-11-12 2:56 ` Ming Lei
2018-11-12 11:02 ` Jan Kara
1 sibling, 0 replies; 4+ messages in thread
From: Ming Lei @ 2018-11-12 2:56 UTC (permalink / raw)
To: Tetsuo Handa
Cc: axboe, Jan Kara, syzbot, linux-block, linux-kernel, syzkaller-bugs
On Sat, Nov 10, 2018 at 05:09:09PM +0900, Tetsuo Handa wrote:
> From 4b9e5556fada37dff1eff13665a229b69e1f7dd8 Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Date: Sat, 10 Nov 2018 17:04:40 +0900
> Subject: [PATCH] loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl().
>
> Commit 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") forgot to
> remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when
> replacing loop_index_mutex with loop_ctl_mutex.
>
> Reported-by: syzbot <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: Jan Kara <jack@suse.cz>
> ---
> drivers/block/loop.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index bf6bc35..176ab1f 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -2074,12 +2074,10 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
> break;
> if (lo->lo_state != Lo_unbound) {
> ret = -EBUSY;
> - mutex_unlock(&loop_ctl_mutex);
> break;
> }
> if (atomic_read(&lo->lo_refcnt) > 0) {
> ret = -EBUSY;
> - mutex_unlock(&loop_ctl_mutex);
> break;
> }
> lo->lo_disk->private_data = NULL;
> --
> 1.8.3.1
>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
--
Ming
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: WARNING: locking bug in loop_control_ioctl
2018-11-10 8:09 ` Tetsuo Handa
2018-11-12 2:56 ` Ming Lei
@ 2018-11-12 11:02 ` Jan Kara
1 sibling, 0 replies; 4+ messages in thread
From: Jan Kara @ 2018-11-12 11:02 UTC (permalink / raw)
To: Tetsuo Handa
Cc: axboe, Jan Kara, syzbot, linux-block, linux-kernel, syzkaller-bugs
On Sat 10-11-18 17:09:09, Tetsuo Handa wrote:
> From 4b9e5556fada37dff1eff13665a229b69e1f7dd8 Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Date: Sat, 10 Nov 2018 17:04:40 +0900
> Subject: [PATCH] loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl().
>
> Commit 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") forgot to
> remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when
> replacing loop_index_mutex with loop_ctl_mutex.
>
> Reported-by: syzbot <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: Jan Kara <jack@suse.cz>
Yeah, my bad. Thanks for fixing this. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> drivers/block/loop.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index bf6bc35..176ab1f 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -2074,12 +2074,10 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
> break;
> if (lo->lo_state != Lo_unbound) {
> ret = -EBUSY;
> - mutex_unlock(&loop_ctl_mutex);
> break;
> }
> if (atomic_read(&lo->lo_refcnt) > 0) {
> ret = -EBUSY;
> - mutex_unlock(&loop_ctl_mutex);
> break;
> }
> lo->lo_disk->private_data = NULL;
> --
> 1.8.3.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-11-09 19:48 WARNING: locking bug in loop_control_ioctl syzbot
2018-11-10 8:09 ` Tetsuo Handa
2018-11-12 2:56 ` Ming Lei
2018-11-12 11:02 ` Jan Kara
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