This is a note to let you know that I've just added the patch titled
scsi: sg: fix blktrace debugfs entries leakage
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-sg-fix-blktrace-debugfs-entries-leakage.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 16176e2729a460f26254bf143981355bcb83b0a6
Author: Yu Kuai <yukuai3@xxxxxxxxxx>
Date: Sat Jun 10 10:20:02 2023 +0800
scsi: sg: fix blktrace debugfs entries leakage
[ Upstream commit db59133e927916d8a25ee1fd8264f2808040909d ]
sg_ioctl() support to enable blktrace, which will create debugfs entries
"/sys/kernel/debug/block/sgx/", however, there is no guarantee that user
will remove these entries through ioctl, and deleting sg device doesn't
cleanup these blktrace entries.
This problem can be fixed by cleanup blktrace while releasing
request_queue, however, it's not a good idea to do this special handling
in common layer just for sg device.
Fix this problem by shutdown bltkrace in sg_device_destroy(), where the
device is deleted and all the users close the device, also grab a
scsi_device reference from sg_add_device() to prevent scsi_device to be
freed before sg_device_destroy();
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230610022003.2557284-3-yukuai1@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 037f8c98a6d36..0adfbd77437f3 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1496,6 +1496,10 @@ sg_add_device(struct device *cl_dev)
int error;
unsigned long iflags;
+ error = scsi_device_get(scsidp);
+ if (error)
+ return error;
+
error = -ENOMEM;
cdev = cdev_alloc();
if (!cdev) {
@@ -1553,6 +1557,7 @@ sg_add_device(struct device *cl_dev)
out:
if (cdev)
cdev_del(cdev);
+ scsi_device_put(scsidp);
return error;
}
@@ -1560,6 +1565,7 @@ static void
sg_device_destroy(struct kref *kref)
{
struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
+ struct request_queue *q = sdp->device->request_queue;
unsigned long flags;
/* CAUTION! Note that the device can still be found via idr_find()
@@ -1567,6 +1573,9 @@ sg_device_destroy(struct kref *kref)
* any other cleanup.
*/
+ blk_trace_remove(q);
+ scsi_device_put(sdp->device);
+
write_lock_irqsave(&sg_index_lock, flags);
idr_remove(&sg_index_idr, sdp->index);
write_unlock_irqrestore(&sg_index_lock, flags);
