[PATCH V2] mtd: rawnand: qcom: fix memory corruption that causes panic

[Manivannan Sadhasivam]

On Thu, Apr 14, 2022 at 05:36:42PM +0200, Miquel Raynal wrote:
> Hi Md,
> 
> quic_mdalam at quicinc.com wrote on Thu, 14 Apr 2022 21:00:17 +0530:
> 
> > 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.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 after nand_scan()
> > returns, and remove updating nandc->max_cwperpage from
> > qcom_nand_attach_chip call back.
> 
> Please update also the commit log.
> 
> Fixes: ?
> Cc: stable ?

Also please add Reported-by to credit Konrad.

Thanks,
Mani

> 
> > Signed-off-by: Md Sadre Alam <quic_mdalam at quicinc.com>
> > Signed-off-by: Sricharan R <quic_srichara at quicinc.com>
> > ---
> > [V2]
> 
> Thanks,
> Miquèl