From: Tetsuo Handa Date: Fri, 4 May 2018 16:58:09 +0000 (-0600) Subject: loop: remember whether sysfs_create_group() was done X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=d3349b6b3c373ac1fbfb040b810fcee5e2adc7e0;p=openwrt%2Fstaging%2Fblogic.git loop: remember whether sysfs_create_group() was done 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 Reported-by: syzbot Reviewed-by: Greg Kroah-Hartman Renamed sysfs_ready -> sysfs_inited. Signed-off-by: Jens Axboe --- diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 5d4e31655d96..5f0df2efc26c 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -809,16 +809,17 @@ 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 b78de9879f4f..4d42c7af7de7 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_inited; struct request_queue *lo_queue; struct blk_mq_tag_set tag_set;