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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2018-05-04 10:58:09 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-17 11:31:46 +0200
commit43991e916eb9eac9ea0ef0317f9bfd3c491972cb (patch)
treeca5ecf5795dc8d0a3a3578c20e2bfa919b1b16dc
parent28db2b23f44c4a15e431327e488fc0680c4aceb0 (diff)
loop: remember whether sysfs_create_group() was done
commit d3349b6b3c373ac1fbfb040b810fcee5e2adc7e0 upstream. 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> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Renamed sysfs_ready -> sysfs_inited. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/block/loop.c11
-rw-r--r--drivers/block/loop.h1
2 files changed, 7 insertions, 5 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index aaa7000a4342..da3902ac16c8 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -835,16 +835,17 @@ static struct attribute_group loop_attribute_group = {
.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_inited = !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_inited)
+ 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 fb2237c73e61..60f0fd2c0c65 100644
--- a/drivers/block/loop.h
+++ b/drivers/block/loop.h
@@ -59,6 +59,7 @@ struct loop_device {
struct kthread_worker worker;
struct task_struct *worker_task;
bool use_dio;
+ bool sysfs_inited;
struct request_queue *lo_queue;
struct blk_mq_tag_set tag_set;