[PATCH v2] mtd: gpmi: Fix NULL pointer dereference
Brian Norris
computersforpeace at gmail.com
Mon Nov 11 14:27:59 EST 2013
On Mon, Nov 11, 2013 at 05:13:41PM -0200, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam at freescale.com>
>
> 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: <stable at vger.kernel.org> # 3.12
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
> ---
> 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)
Signed-off-by: Brian Norris <computersforpeace at gmail.com>
I'll give Huang a chance to comment before pulling this in.
Thanks,
Brian
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