From: Fabio Estevam <[email protected]>
Currently mx23_check_transcription_stamp() uses chip->buffers->databuf
as its buffer, which is allocated by nand_scan_tail().
Since commit 720e7ce5 ("mtd: gpmi: remove the nand_scan()"),
mx23_check_transcription_stamp() is called before nand_scan_tail(), which causes
a NULL pointer dereference:
[ 1.150000] NAND device: Manufacturer ID: 0xec, Chip ID: 0xd7 (Samsung NAND
4GiB 3,3V 8-bit), 4096MiB, page size: 4096, OOB size: 8
[ 1.160000] Unable to handle kernel NULL pointer dereference at virtual
address 000005d0
[ 1.170000] pgd = c0004000
[ 1.170000] [000005d0] *pgd=00000000
[ 1.180000] Internal error: Oops: 5 [#1] ARM
[ 1.180000] Modules linked in:
[ 1.180000] CPU: 0 PID: 1 Comm: swapper Not tainted 3.12.0 #89
[ 1.180000] task: c7440000 ti: c743a000 task.ti: c743a000
[ 1.180000] PC is at memcmp+0x10/0x54
[ 1.180000] LR is at gpmi_nand_probe+0x42c/0x894
[ 1.180000] pc : [<c025fcb0>] lr : [<c02f6a68>] psr: 20000053
[ 1.180000] sp : c743be2c ip : 600000d3 fp : ffffffff
[ 1.180000] r10: 000005d0 r9 : c02f5f08 r8 : 00000000
[ 1.180000] r7 : c75858a8 r6 : c75858a8 r5 : c7585b18 r4 : c7585800
[ 1.180000] r3 : 000005d0 r2 : 00000004 r1 : c05c33e4 r0 : 000005d0
[ 1.180000] Flags: nzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment
kernel
[ 1.180000] Control: 0005317f Table: 40004000 DAC: 00000017
[ 1.180000] Process swapper (pid: 1, stack limit = 0xc743a1c0)
In order to fix this problem, allocate the buffer locally via kzalloc().
Also, as mx23_check_transcription_stamp() can return en error code now, adapt
the logic in mx23_boot_init() to take this into account.
Cc: <[email protected]> # 3.12
Signed-off-by: Fabio Estevam <[email protected]>
---
Changes since v1:
- Drop sizeof(*buffer) from size calculatio in kzalloc (Brian Norris)
- Propagate the error if mx23_check_transcription_stamp returns a negative
error code (Brian Norris)
drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
index a9830ff..f99b876 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
@@ -1342,7 +1342,7 @@ static int mx23_check_transcription_stamp(struct
gpmi_nand_data *this)
unsigned int search_area_size_in_strides;
unsigned int stride;
unsigned int page;
- uint8_t *buffer = chip->buffers->databuf;
+ uint8_t *buffer;
int saved_chip_number;
int found_an_ncb_fingerprint = false;
@@ -1352,6 +1352,9 @@ static int mx23_check_transcription_stamp(struct
gpmi_nand_data *this)
saved_chip_number = this->current_chip;
chip->select_chip(mtd, 0);
+ buffer = kzalloc(strlen(fingerprint), GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
/*
* Loop through the first search area, looking for the NCB fingerprint.
*/
@@ -1380,6 +1383,8 @@ static int mx23_check_transcription_stamp(struct
gpmi_nand_data *this)
chip->select_chip(mtd, saved_chip_number);
+ kfree(buffer);
+
if (found_an_ncb_fingerprint)
dev_dbg(dev, "\tFound a fingerprint\n");
else
@@ -1488,7 +1493,11 @@ static int mx23_boot_init(struct gpmi_nand_data *this)
* transcription stamp. If we find it, then we don't have to do
* anything -- the block marks are already transcribed.
*/
- if (mx23_check_transcription_stamp(this))
+
+ ret = mx23_check_transcription_stamp(this);
+ if (ret < 0)
+ return ret;
+ else if (ret)
return 0;
/*
--
1.8.1.2
--
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