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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Zhihao Cheng <chengzhihao1@huawei.com>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        syzbot+d9aab50b1154e3d163f5@syzkaller.appspotmail.com,
        Richard Weinberger <richard@nod.at>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 174/232] ubi: fastmap: Dont produce the initial next anchor PEB when fastmap is disabled
Date:   Thu, 20 Aug 2020 11:20:25 +0200
Message-Id: <20200820091621.246072260@linuxfoundation.org>
In-Reply-To: <20200820091612.692383444@linuxfoundation.org>
References: <20200820091612.692383444@linuxfoundation.org>
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From: Zhihao Cheng <chengzhihao1@huawei.com>

[ Upstream commit 3b185255bb2f34fa6927619b9ef27f192a3d9f5a ]

Following process triggers a memleak caused by forgetting to release the
initial next anchor PEB (CONFIG_MTD_UBI_FASTMAP is disabled):
1. attach -> __erase_worker -> produce the initial next anchor PEB
2. detach -> ubi_fastmap_close (Do nothing, it should have released the
   initial next anchor PEB)

Don't produce the initial next anchor PEB in __erase_worker() when fastmap
is disabled.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Suggested-by: Sascha Hauer <s.hauer@pengutronix.de>
Fixes: f9c34bb529975fe ("ubi: Fix producing anchor PEBs")
Reported-by: syzbot+d9aab50b1154e3d163f5@syzkaller.appspotmail.com
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mtd/ubi/wl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 27636063ed1bb..42cac572f82dc 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -1086,7 +1086,8 @@ static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk)
 	if (!err) {
 		spin_lock(&ubi->wl_lock);
 
-		if (!ubi->fm_next_anchor && e->pnum < UBI_FM_MAX_START) {
+		if (!ubi->fm_disabled && !ubi->fm_next_anchor &&
+		    e->pnum < UBI_FM_MAX_START) {
 			/* Abort anchor production, if needed it will be
 			 * enabled again in the wear leveling started below.
 			 */
-- 
2.25.1