linux-kernel - [PATCH 5.0 098/139] dm mpath: always free attached_handler_name in parse

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Date:   Thu, 23 May 2019 21:06:26 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Yufen Yu <yuyufen@...wei.com>,
        Martin Wilck <mwilck@...e.com>,
        Mike Snitzer <snitzer@...hat.com>
Subject: [PATCH 5.0 098/139] dm mpath: always free attached_handler_name in parse_path()

From: Martin Wilck <mwilck@...e.com>

commit 940bc471780b004a5277c1931f52af363c2fc9da upstream.

Commit b592211c33f7 ("dm mpath: fix attached_handler_name leak and
dangling hw_handler_name pointer") fixed a memory leak for the case
where setup_scsi_dh() returns failure. But setup_scsi_dh may return
success and not "use" attached_handler_name if the
retain_attached_hwhandler flag is not set on the map. As setup_scsi_sh
properly "steals" the pointer by nullifying it, freeing it
unconditionally in parse_path() is safe.

Fixes: b592211c33f7 ("dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointer")
Cc: stable@...r.kernel.org
Reported-by: Yufen Yu <yuyufen@...wei.com>
Signed-off-by: Martin Wilck <mwilck@...e.com>
Signed-off-by: Mike Snitzer <snitzer@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/md/dm-mpath.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -882,6 +882,7 @@ static struct pgpath *parse_path(struct
 	if (attached_handler_name || m->hw_handler_name) {
 		INIT_DELAYED_WORK(&p->activate_path, activate_path_work);
 		r = setup_scsi_dh(p->path.dev->bdev, m, &attached_handler_name, &ti->error);
+		kfree(attached_handler_name);
 		if (r) {
 			dm_put_device(ti, p->path.dev);
 			goto bad;
@@ -896,7 +897,6 @@ static struct pgpath *parse_path(struct
 
 	return p;
  bad:
-	kfree(attached_handler_name);
 	free_pgpath(p);
 	return ERR_PTR(r);
 }