From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: syzbot
<bot+9f03168400f56df89dbc6f1751f4458fe739ff29@syzkaller.appspotmail.com>,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
Jens Axboe <axboe@kernel.dk>
Cc: dvyukov@google.com, gregkh@linuxfoundation.org
Subject: Re: WARNING in sysfs_remove_group
Date: Wed, 2 May 2018 23:11:59 +0900 [thread overview]
Message-ID: <55ff5960-eaab-5a36-5605-4e2230b77607@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <94eb2c030882b2b1b505610813df@google.com>
syzbot has hit this bug for nearly 6000 times. Why not to fix this trivial one? ;-)
>From 626d33de1b70b11ecaf95a9f83f7644998e54cbb Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Wed, 2 May 2018 23:03:48 +0900
Subject: [PATCH] loop: remember whether sysfs_create_group() succeeded
syzbot is hitting WARN() triggered by memory allocation fault
injection [1] because loop module is calling sysfs_remove_group()
when sysfs_create_group() failed.
Fix this by remembering whether sysfs_create_group() succeeded.
[1] https://syzkaller.appspot.com/bug?id=3f86c0edf75c86d2633aeb9dd69eccc70bc7e90b
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+9f03168400f56df89dbc6f1751f4458fe739ff29@syzkaller.appspotmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
---
drivers/block/loop.c | 11 ++++++-----
drivers/block/loop.h | 1 +
2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 5d4e316..1d758d8 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -809,16 +809,17 @@ static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf)
.attrs= loop_attrs,
};
-static int loop_sysfs_init(struct loop_device *lo)
+static void loop_sysfs_init(struct loop_device *lo)
{
- return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj,
- &loop_attribute_group);
+ lo->sysfs_ready = !sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj,
+ &loop_attribute_group);
}
static void loop_sysfs_exit(struct loop_device *lo)
{
- sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,
- &loop_attribute_group);
+ if (lo->sysfs_ready)
+ sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,
+ &loop_attribute_group);
}
static void loop_config_discard(struct loop_device *lo)
diff --git a/drivers/block/loop.h b/drivers/block/loop.h
index b78de98..73c801f 100644
--- a/drivers/block/loop.h
+++ b/drivers/block/loop.h
@@ -58,6 +58,7 @@ struct loop_device {
struct kthread_worker worker;
struct task_struct *worker_task;
bool use_dio;
+ bool sysfs_ready;
struct request_queue *lo_queue;
struct blk_mq_tag_set tag_set;
--
1.8.3.1
next prev parent reply other threads:[~2018-05-02 14:11 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <001a113ed2fa7bedfe055c8316a5@google.com>
2017-10-27 8:43 ` WARNING in sysfs_remove_group Greg KH
2017-10-27 9:10 ` Dmitry Vyukov
2017-10-27 9:23 ` Greg KH
2017-10-27 9:30 ` Dmitry Vyukov
2017-12-23 20:50 ` syzbot
2018-05-02 14:11 ` Tetsuo Handa [this message]
2018-05-02 14:24 ` Greg KH
2018-05-04 11:47 ` [PATCH] loop: remember whether sysfs_create_group() succeeded Tetsuo Handa
2018-05-04 14:15 ` Jens Axboe
2018-05-04 14:27 ` Tetsuo Handa
2018-05-04 14:30 ` Jens Axboe
2018-05-04 14:40 ` Tetsuo Handa
2018-05-04 14:43 ` Jens Axboe
2018-05-04 16:14 ` [PATCH v2] " Tetsuo Handa
2018-05-04 16:27 ` Jens Axboe
2018-05-04 16:47 ` Tetsuo Handa
2018-05-05 10:46 ` [PATCH] " Milan Broz
2018-05-05 11:49 ` Tetsuo Handa
2018-05-08 9:02 ` Milan Broz
2018-05-09 12:31 ` Jan Kara
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