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Commit b2660f35 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Greg Kroah-Hartman
Browse files

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: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: default avatarsyzbot <syzbot+9f03168400f56df89dbc6f1751f4458fe739ff29@syzkaller.appspotmail.com>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Renamed sysfs_ready -> sysfs_inited.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 684db31e

drivers/block/loop.c

+6 −5
Original line number Diff line number Diff line
@@ -824,14 +824,15 @@ 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,

	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)

{

	if (lo->sysfs_inited)

		sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,

				   &loop_attribute_group);

}

drivers/block/loop.h

+1 −0
Original line number Diff line number Diff line
@@ -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;