From: Huang Shijie Date: Tue, 12 Nov 2013 04:23:08 +0000 (+0800) Subject: mtd: gpmi: fix the NULL pointer X-Git-Tag: firefly_0821_release~176^2~4985^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=885d71e5838f68d5dbee92ab952cc90ad6c1dc6b;p=firefly-linux-kernel-4.4.55.git mtd: gpmi: fix the NULL pointer The imx23 board will check the fingerprint, so it will call the mx23_check_transcription_stamp. This function will use @chip->buffers->databuf as its buffer which is allocated in the nand_scan_tail(). Unfortunately, the mx23_check_transcription_stamp is called before the nand_scan_tail(). So we will meet a NULL pointer bug: -------------------------------------------------------------------- [ 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 : [] lr : [] 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) -------------------------------------------------------------------- This patch rearrange the init procedure: Set the NAND_SKIP_BBTSCAN to skip the nand scan firstly, and after we set the proper settings, we will call the chip->scan_bbt() manually. Cc: stable@vger.kernel.org # 3.12 Signed-off-by: Huang Shijie Reported-by: Fabio Estevam Tested-by: Fabio Estevam Signed-off-by: Brian Norris --- diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c index c7243dca90fd..dabbc14db563 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c @@ -1578,8 +1578,6 @@ static int gpmi_set_geometry(struct gpmi_nand_data *this) static int gpmi_pre_bbt_scan(struct gpmi_nand_data *this) { - int ret; - /* Set up swap_block_mark, must be set before the gpmi_set_geometry() */ if (GPMI_IS_MX23(this)) this->swap_block_mark = false; @@ -1587,12 +1585,8 @@ static int gpmi_pre_bbt_scan(struct gpmi_nand_data *this) this->swap_block_mark = true; /* Set up the medium geometry */ - ret = gpmi_set_geometry(this); - if (ret) - return ret; + return gpmi_set_geometry(this); - /* NAND boot init, depends on the gpmi_set_geometry(). */ - return nand_boot_init(this); } static void gpmi_nfc_exit(struct gpmi_nand_data *this) @@ -1682,10 +1676,16 @@ static int gpmi_nfc_init(struct gpmi_nand_data *this) if (ret) goto err_out; + chip->options |= NAND_SKIP_BBTSCAN; ret = nand_scan_tail(mtd); if (ret) goto err_out; + ret = nand_boot_init(this); + if (ret) + goto err_out; + chip->scan_bbt(mtd); + ppdata.of_node = this->pdev->dev.of_node; ret = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0); if (ret)