linux-kernel - [PATCH 3.16 069/157] mtd: cfi: fix deadloop in cfi_cmdset_0002.c do_write

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Message-ID: <lsq.1565469607.292130683@decadent.org.uk>
Date:   Sat, 10 Aug 2019 21:40:07 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Tokunori Ikegami" <ikegami_to@...oo.co.jp>,
        "Richard Weinberger" <richard@....at>,
        "Liu Jian" <liujian56@...wei.com>,
        "Yi Huaijie" <yihuaijie@...wei.com>
Subject: [PATCH 3.16 069/157] mtd: cfi: fix deadloop in cfi_cmdset_0002.c
 do_write_buffer

3.16.72-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Liu Jian <liujian56@...wei.com>

commit d9b8a67b3b95a5c5aae6422b8113adc1c2485f2b upstream.

In function do_write_buffer(), in the for loop, there is a case
chip_ready() returns 1 while chip_good() returns 0, so it never
break the loop.
To fix this, chip_good() is enough and it should timeout if it stay
bad for a while.

Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
Signed-off-by: Yi Huaijie <yihuaijie@...wei.com>
Signed-off-by: Liu Jian <liujian56@...wei.com>
Reviewed-by: Tokunori Ikegami <ikegami_to@...oo.co.jp>
Signed-off-by: Richard Weinberger <richard@....at>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/mtd/chips/cfi_cmdset_0002.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -1538,7 +1538,11 @@ static int __xipram do_write_buffer(stru
 			continue;
 		}
 
-		if (time_after(jiffies, timeo) && !chip_ready(map, adr))
+		/*
+		 * We check "time_after" and "!chip_good" before checking "chip_good" to avoid
+		 * the failure due to scheduling.
+		 */
+		if (time_after(jiffies, timeo) && !chip_good(map, adr, datum))
 			break;
 
 		if (chip_good(map, adr, datum)) {