From: Omar Sandoval <osandov@osandov.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
viro@zeniv.linux.org.uk, osandov@fb.com, dvyukov@google.com,
bot+abdba5bc6de135d7622f00756da97998425b6de5@syzkaller.appspotmail.com,
axboe@kernel.dk, tom.leiming@gmail.com, hare@suse.de,
shli@fb.com, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com, mingo@redhat.com,
linux-fsdevel@vger.kernel.org, knikanth@suse.de
Subject: Re: INFO: task hung in lo_ioctl
Date: Fri, 6 Apr 2018 08:59:05 -0700 [thread overview]
Message-ID: <20180406155905.GA11697@vader> (raw)
In-Reply-To: <20180406154343.GK4082@hirez.programming.kicks-ass.net>
On Fri, Apr 06, 2018 at 05:43:43PM +0200, Peter Zijlstra wrote:
> On Fri, Apr 06, 2018 at 10:55:03PM +0900, Tetsuo Handa wrote:
> > Peter Zijlstra wrote:
> > > On Fri, Apr 06, 2018 at 09:04:18PM +0900, Tetsuo Handa wrote:
> > > > + /* Temporary hack for handling lock imbalance. */
> > > > + if (__mutex_owner(&lo->lo_ctl_mutex) == current)
> > > > + mutex_unlock(&lo->lo_ctl_mutex);
> > >
> > > ARGGH.. you didn't read the comment we put on that?
> > >
> >
> > Commit 5b52330bbfe63b33 ("audit: fix auditd/kernel connection state tracking")
> > is using __mutex_owner(). ;-)
>
> That got removed and the warning added.
Seems easy enough to fix without resorting to __mutex_owner() (untested):
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 264abaaff662..cee258d12a1e 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1300,12 +1300,13 @@ loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) {
static int
loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
struct loop_info64 info64;
- int err = 0;
+ int err;
- if (!arg)
- err = -EINVAL;
- if (!err)
- err = loop_get_status(lo, &info64);
+ if (!arg) {
+ mutex_unlock(&lo->lo_ctl_mutex);
+ return -EINVAL;
+ }
+ err = loop_get_status(lo, &info64);
if (!err && copy_to_user(arg, &info64, sizeof(info64)))
err = -EFAULT;
I'll test it and send it up when I get into the office.
next prev parent reply other threads:[~2018-04-06 15:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <94eb2c0810d04f5a46055ffc71aa@google.com>
[not found] ` <CACT4Y+Y6UhNQOc7VUPgvXZ3yGPusjg2WJ9-OXMCRGM2Q1bx7ZQ@mail.gmail.com>
2018-04-04 15:23 ` INFO: task hung in lo_ioctl Tetsuo Handa
2018-04-06 12:04 ` Tetsuo Handa
2018-04-06 12:14 ` Peter Zijlstra
2018-04-06 13:55 ` Tetsuo Handa
2018-04-06 15:43 ` Peter Zijlstra
2018-04-06 15:59 ` Omar Sandoval [this message]
2019-01-19 18:56 ` Dmitry Vyukov
2019-01-20 2:35 ` Tetsuo Handa
2019-01-20 9:49 ` Dmitry Vyukov
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