From: Brent Taylor motobud@gmail.com

Gregg, I apologize for the 4.4.y patch, I screwed up the branching in my local tree and tried to submit one patch that would cover versions 4.4.y and 3.18.y. Here is a valid 4.4.y patch. -- Brent

commit 30863e38ebeb500a31cecee8096fb5002677dd9b upstream.

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 # 4.4.x Signed-off-by: Brent Taylor motobud@gmail.com --- drivers/mtd/nand/nand_base.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 54ab48827258..7ba109e8cf88 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2663,15 +2663,18 @@ 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->priv; + 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;