The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 30863e38ebeb500a31cecee8096fb5002677dd9b Mon Sep 17 00:00:00 2001
From: Brent Taylor motobud@gmail.com Date: Mon, 30 Oct 2017 22:32:45 -0500 Subject: [PATCH] mtd: nand: Fix writing mtdoops to nand flash.
When mtdoops calls mtd_panic_write(), it eventually calls panic_nand_write() in nand_base.c. In order to properly wait for the nand chip to be ready in panic_nand_wait(), the chip must first be selected.
When using the atmel nand flash controller, a panic would occur due to a NULL pointer exception.
Fixes: 2af7c6539931 ("mtd: Add panic_write for NAND flashes") Cc: stable@vger.kernel.org Signed-off-by: Brent Taylor motobud@gmail.com Signed-off-by: Boris Brezillon boris.brezillon@free-electrons.com
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 4c867115c53b..e48bf8260f54 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2799,15 +2799,18 @@ static int panic_nand_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const uint8_t *buf) { struct nand_chip *chip = mtd_to_nand(mtd); + int chipnr = (int)(to >> chip->chip_shift); struct mtd_oob_ops ops; int ret;
- /* Wait for the device to get ready */ - panic_nand_wait(mtd, chip, 400); - /* Grab the device */ panic_nand_get_device(chip, mtd, FL_WRITING);
+ chip->select_chip(mtd, chipnr); + + /* Wait for the device to get ready */ + panic_nand_wait(mtd, chip, 400); + memset(&ops, 0, sizeof(ops)); ops.len = len; ops.datbuf = (uint8_t *)buf;