[PATCH] mtd: gpmi-nand: Fix kernel crash due to missing verify_buf

Fabio Estevam
2012-08-10T22:48:48Z

From: Fabio Estevam <fabio.estevam@freescale.com>

When selecting CONFIG_MTD_NAND_VERIFY_WRITE=y and doing simple write tests the following kernel crash happens:

root@freescale /$ dd if=/dev/zero of=/dev/mtd0 bs=128k count=1
[ 41.070000] Unable to handle kernel NULL pointer dereference at virtual addr0
[ 41.080000] pgd = c77ac000
[ 41.080000] [00000000] *pgd=4773c831, *pte=00000000, *ppte=00000000
[ 41.090000] Internal error: Oops: 17 [#1] ARM
[ 41.090000] Modules linked in:
[ 41.090000] CPU: 0 Not tainted (3.6.0-rc1-next-20120809-00002-ga25d017-d)
[ 41.090000] PC is at nand_verify_buf+0x18/0x5c
[ 41.090000] LR is at nand_write_page+0xc0/0x140
[ 41.090000] pc : [<c023e7d4>] lr : [<c023fcfc>] psr: 20000013
[ 41.090000] sp : c7779de4 ip : 00000000 fp : c6e60000
[ 41.090000] r10: 00000000 r9 : 00020000 r8 : 00000000
[ 41.090000] r7 : 00000000 r6 : c6e60000 r5 : c762cb10 r4 : 00000000
[ 41.090000] r3 : c762c8a8 r2 : 00000800 r1 : c6e60000 r0 : 00000000
[ 41.090000] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 41.090000] Control: 0005317f Table: 477ac000 DAC: 00000015
[ 41.090000] Process dd (pid: 427, stack limit = 0xc7778270)
[ 41.090000] Stack: (0xc7779de4 to 0xc777a000)
...

The NULL pointer dereference that happens in nand_verify_buf() is due to the missing
gpmi_verify_buf implementation in the gpmi-nand driver.

Implement gpmi_verify_buf() to prevent this crash.

Cc: <stable@vger.kernel.org>
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 18 ++++++++++++++++++
drivers/mtd/nand/gpmi-nand/gpmi-nand.h | 1 +
2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
index 8c0d2f0..72b25ce 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
@@ -1533,6 +1533,23 @@ void gpmi_nfc_exit(struct gpmi_nand_data *this)
gpmi_free_dma_buffer(this);
}

+static int gpmi_verify_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
+{
+ struct nand_chip *nand = mtd->priv;
+ struct gpmi_nand_data *data = container_of(mtd, struct gpmi_nand_data,
+ mtd);
+ int ret;
+
+ ret = nand->ecc.read_page(mtd, nand, data->verify_buf, 0, 0);
+ if (ret)
+ return -EFAULT;
+
+ if (memcmp(buf, data->verify_buf, len))
+ return -EFAULT;
+
+ return 0;
+}
+
static int __devinit gpmi_nfc_init(struct gpmi_nand_data *this)
{
struct mtd_info *mtd = &this->mtd;
@@ -1555,6 +1572,7 @@ static int __devinit gpmi_nfc_init(struct gpmi_nand_data *this)
chip->dev_ready = gpmi_dev_ready;
chip->read_byte = gpmi_read_byte;
chip->read_buf = gpmi_read_buf;
+ chip->verify_buf = gpmi_verify_buf;
chip->write_buf = gpmi_write_buf;
chip->ecc.read_page = gpmi_ecc_read_page;
chip->ecc.write_page = gpmi_ecc_write_page;
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
index 1547a60..cd9bdf7 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
@@ -148,6 +148,7 @@ struct gpmi_nand_data {
/* General-use Variables */
int current_chip;
unsigned int command_length;
+ uint8_t verify_buf[NAND_MAX_PAGESIZE];

/* passed from upper layer */
uint8_t *upper_buf;
--
1.7.1