linux-kernel - [PATCH] mmc: fix host release issue after discard operation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1C995FCD38EDD646A035D3E5892E8C7C04C189A8@SJEXCHMB13.corp.ad.broadcom.com>
Date:	Thu, 24 Oct 2013 22:13:33 +0000
From:	"Ray Jui" <rjui@...adcom.com>
To:	"Chris Ball" <cjb@...top.org>,
	"Seungwon Jeon" <tgih.jun@...sung.com>
cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] mmc: fix host release issue after discard operation

Under function mmc_blk_issue_rq, after an MMC discard operation,
the MMC request data structure may be freed in memory. Later in
the same function, the check of req->cmd_flags & MMC_REQ_SPECIAL_MASK
is dangerous and invalid. It causes the MMC host not being released
when it should

This patch fixes the issue by marking the special request down before
the discard/flush operation

Reported by: Harold (SoonYeal) Yang <haroldsy@...adcom.com>
Signed-off-by: Ray Jui <rjui@...adcom.com>
---
 drivers/mmc/card/block.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 1a3163f..9e8e970 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -1954,7 +1954,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
 
 static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 {
-	int ret;
+	int ret, req_is_special = 0;
 	struct mmc_blk_data *md = mq->data;
 	struct mmc_card *card = md->queue.card;
 	struct mmc_host *host = card->host;
@@ -1973,6 +1973,10 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 		goto out;
 	}
 
+	/* mark special request here since req may be freed later */
+	if (req && (req->cmd_flags & MMC_REQ_SPECIAL_MASK))
+		req_is_special = 1;
+
 	mq->flags &= ~MMC_QUEUE_NEW_REQUEST;
 	if (req && req->cmd_flags & REQ_DISCARD) {
 		/* complete ongoing async transfer before issuing discard */
@@ -1999,7 +2003,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 
 out:
 	if ((!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST)) ||
-	     (req && (req->cmd_flags & MMC_REQ_SPECIAL_MASK)))
+	     req_is_special)
 		/*
 		 * Release host when there are no more requests
 		 * and after special request(discard, flush) is done.
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/