[PATCH V4] mtd: rawnand: qcom: fix memory corruption that causes panic
Md Sadre Alam
quic_mdalam at quicinc.com
Mon Apr 18 00:49:13 PDT 2022
On 4/18/2022 12:06 PM, Manivannan Sadhasivam wrote:
> On Mon, Apr 18, 2022 at 11:53:11AM +0530, Md Sadre Alam wrote:
>> This patch fixes a memory corruption that occurred in the
>> nand_scan() path for Hynix nand device.
>>
>> On boot, for Hynix nand device will panic at a weird place:
>> | Unable to handle kernel NULL pointer dereference at virtual
>> address 00000070
>> | [00000070] *pgd=00000000
>> | Internal error: Oops: 5 [#1] PREEMPT SMP ARM
>> | Modules linked in:
>> | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.0-01473-g13ae1769cfb0
>> #38
>> | Hardware name: Generic DT based system
>> | PC is at nandc_set_reg+0x8/0x1c
>> | LR is at qcom_nandc_command+0x20c/0x5d0
>> | pc : [<c088b74c>] lr : [<c088d9c8>] psr: 00000113
>> | sp : c14adc50 ip : c14ee208 fp : c0cc970c
>> | r10: 000000a3 r9 : 00000000 r8 : 00000040
>> | r7 : c16f6a00 r6 : 00000090 r5 : 00000004 r4 :c14ee040
>> | r3 : 00000000 r2 : 0000000b r1 : 00000000 r0 :c14ee040
>> | Flags: nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
>> | Control: 10c5387d Table: 8020406a DAC: 00000051
>> | Register r0 information: slab kmalloc-2k start c14ee000 pointer offset
>> 64 size 2048
>> | Process swapper/0 (pid: 1, stack limit = 0x(ptrval))
>> | nandc_set_reg from qcom_nandc_command+0x20c/0x5d0
>> | qcom_nandc_command from nand_readid_op+0x198/0x1e8
>> | nand_readid_op from hynix_nand_has_valid_jedecid+0x30/0x78
>> | hynix_nand_has_valid_jedecid from hynix_nand_init+0xb8/0x454
>> | hynix_nand_init from nand_scan_with_ids+0xa30/0x14a8
>> | nand_scan_with_ids from qcom_nandc_probe+0x648/0x7b0
>> | qcom_nandc_probe from platform_probe+0x58/0xac
>>
>> The problem is that the nand_scan()'s qcom_nand_attach_chip callback
>> is updating the nandc->max_cwperpage from 1 to 4 or 8 based on page size.
>> This causes the sg_init_table of clear_bam_transaction() in the driver's
>> qcom_nandc_command() to memset much more than what was initially
>> allocated by alloc_bam_transaction().
>>
>> This patch will update nandc->max_cwperpage 1 to 4 or 8 based on page
>> size in qcom_nand_attach_chip call back after freeing the previously
>> allocated memory for bam txn as per nandc->max_cwperpage = 1 and then
>> again allocating bam txn as per nandc->max_cwperpage = 4 or 8 based on
>> page size in qcom_nand_attach_chip call back itself.
>>
>> Cc: stable at vger.kernel.org
>> Fixes: 6a3cec64f18c ("mtd: rawnand: qcom: convert driver to nand_scan()")
>> Reported-by: Konrad Dybcio <konrad.dybcio at somainline.org>
>> Signed-off-by: Md Sadre Alam <quic_mdalam at quicinc.com>
>> Signed-off-by: Sricharan R <quic_srichara at quicinc.com>
> I know that you and Sri were involved in creating this patch. So there should
> be a co-developed-by tag for Sri and your signed-off-by should be the last one.
> Like below,
Updated in V5 patch.
>
> Cc: stable at vger.kernel.org
> Fixes: 6a3cec64f18c ("mtd: rawnand: qcom: convert driver to nand_scan()")
> Reported-by: Konrad Dybcio <konrad.dybcio at somainline.org>
> Co-developed-by: Sricharan R <quic_srichara at quicinc.com>
> Signed-off-by: Sricharan R <quic_srichara at quicinc.com>
> Signed-off-by: Md Sadre Alam <quic_mdalam at quicinc.com>
>
> With that,
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
Updated in V5 patch.
>
> Thanks,
> Mani
>
>> ---
>> Changes in V4:
>>
>> * Incorporated "commit log wrong" comment from Mani
>> * Updated commit log
>>
>> Changes in V3:
>>
>> * Incorporated "Fixes tags are missing" comment from Miquèl
>> * Added Fixes tag Fixes:6a3cec64f18c ("mtd: rawnand: qcom: convert driver to nand_scan()")
>> * Incorporated "stable tag missing" comment from Miquèl
>> * Added stable tag Cc: stable at vger.kernel.org
>> * Incorporated "Reported-by tag missing" comment from Mani
>> * Added Reported-by tag Reported-by: Konrad Dybcio <konrad.dybcio at somainline.org>
>>
>> Changes in V2:
>>
>> * Incorporated "alloc_bam_transaction inside qcom_nand_attach_chip" suggestion from Mani
>> * Freed previously alloacted memory for bam txn before updating max_cwperpage inside
>> qcom_nand_attach_chip().
>> * Moved alloc_bam_transaction() inside qcom_nand_attach_chip(). after upding max_cwperpage
>> 4 or 8 based on page size.
>>
>> drivers/mtd/nand/raw/qcom_nandc.c | 24 +++++++++++++-----------
>> 1 file changed, 13 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
>> index 1a77542..048b255 100644
>> --- a/drivers/mtd/nand/raw/qcom_nandc.c
>> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
>> @@ -2651,10 +2651,23 @@ static int qcom_nand_attach_chip(struct nand_chip *chip)
>> ecc->engine_type = NAND_ECC_ENGINE_TYPE_ON_HOST;
>>
>> mtd_set_ooblayout(mtd, &qcom_nand_ooblayout_ops);
>> + /* Free the initially allocated BAM transaction for reading the ONFI params */
>> + if (nandc->props->is_bam)
>> + free_bam_transaction(nandc);
>>
>> nandc->max_cwperpage = max_t(unsigned int, nandc->max_cwperpage,
>> cwperpage);
>>
>> + /* Now allocate the BAM transaction based on updated max_cwperpage */
>> + if (nandc->props->is_bam) {
>> + nandc->bam_txn = alloc_bam_transaction(nandc);
>> + if (!nandc->bam_txn) {
>> + dev_err(nandc->dev,
>> + "failed to allocate bam transaction\n");
>> + return -ENOMEM;
>> + }
>> + }
>> +
>> /*
>> * DATA_UD_BYTES varies based on whether the read/write command protects
>> * spare data with ECC too. We protect spare data by default, so we set
>> @@ -2955,17 +2968,6 @@ static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
>> if (ret)
>> return ret;
>>
>> - if (nandc->props->is_bam) {
>> - free_bam_transaction(nandc);
>> - nandc->bam_txn = alloc_bam_transaction(nandc);
>> - if (!nandc->bam_txn) {
>> - dev_err(nandc->dev,
>> - "failed to allocate bam transaction\n");
>> - nand_cleanup(chip);
>> - return -ENOMEM;
>> - }
>> - }
>> -
>> ret = mtd_device_parse_register(mtd, probes, NULL, NULL, 0);
>> if (ret)
>> nand_cleanup(chip);
>> --
>> 2.7.4
>>
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