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@vger.kernel.org Fixes: 6a3cec64f18c ("mtd: rawnand: qcom: convert driver to nand_scan()") Reported-by: Konrad Dybcio konrad.dybcio@somainline.org Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Co-developed-by: Sricharan R quic_srichara@quicinc.com Signed-off-by: Sricharan R quic_srichara@quicinc.com Signed-off-by: Md Sadre Alam quic_mdalam@quicinc.com --- Changes in V5:

* Incorporated "missing Co-developed-by tag" comment from Mani * Added Co-developed-by tag Co-developed-by: Sricharan R quic_srichara@quicinc.com * Incorporated " Add Reviewed-by tag" comment from Mani * Added Reviewed-by tag Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org

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@vger.kernel.org * Incorporated "Reported-by tag missing" comment from Mani * Added Reported-by tag Reported-by: Konrad Dybcio konrad.dybcio@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);