On Mon, 2022-04-18 at 07:48:27 UTC, 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@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
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/fixes, thanks.
Miquel