linux-kernel - [PATCH] vmw_balloon: release lock on error in vmballoon

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Date:   Mon, 11 Feb 2019 21:45:45 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Julien Freche <jfreche@...are.com>,
        Xavier Deguillard <xdeguillard@...are.com>,
        Nadav Amit <namit@...are.com>
Cc:     "VMware, Inc." <pv-drivers@...are.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH] vmw_balloon: release lock on error in vmballoon_reset()

We added some locking to this function but forgot to drop the lock on
these two error paths.  This bug would lead to an immediate deadlock.

Fixes: c7b3690fb152 ("vmw_balloon: stats rework")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
 drivers/misc/vmw_balloon.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 6542a7711cac..ad807d5a3141 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1330,7 +1330,7 @@ static void vmballoon_reset(struct vmballoon *b)
 	vmballoon_pop(b);
 
 	if (vmballoon_send_start(b, VMW_BALLOON_CAPABILITIES))
-		return;
+		goto unlock;
 
 	if ((b->capabilities & VMW_BALLOON_BATCHED_CMDS) != 0) {
 		if (vmballoon_init_batching(b)) {
@@ -1341,7 +1341,7 @@ static void vmballoon_reset(struct vmballoon *b)
 			 * The guest will retry in one second.
 			 */
 			vmballoon_send_start(b, 0);
-			return;
+			goto unlock;
 		}
 	} else if ((b->capabilities & VMW_BALLOON_BASIC_CMDS) != 0) {
 		vmballoon_deinit_batching(b);
@@ -1357,6 +1357,7 @@ static void vmballoon_reset(struct vmballoon *b)
 	if (vmballoon_send_guest_id(b))
 		pr_err("failed to send guest ID to the host\n");
 
+unlock:
 	up_write(&b->conf_sem);
 }
 
-- 
2.17.1