Regression in backport MEMREAD ioctl ? [Was: Re: mt7622: belkin-rt3200: r22602-42eeb22450: Kernel panic: kernel stack overflow]

[Hauke Mehrtens]

On 4/21/23 15:17, Michał Kępień wrote:
> Hi Petr,
> 
>>> Since the crash happens right after snand driver initialization, I think the
>>> most likely candidate is this one:
>>> fa4dc86e9808 kernel: backport MEMREAD ioctl
>>>
>>> Maybe there are still some stack declarations of struct mtd_oob_ops left
>>> that aren't fully initialized.
>>
>> thanks for looking into that Felix, Michał any idea what might be wrong here?
> 
> I remember looking for uninitialized fields in all existing instances of
> struct mtd_oob_ops in version 5.15.98 of the Linux kernel source tree
> while preparing the MEMREAD backports.  However, it did not occur to me
> to check OpenWRT-specific patches in the same way (sorry!) - and a naïve
> search uncovers these two locations:
> 
>      $ git grep -E 'struct mtd_oob_ops [^=*{}]+;' -- ':!target/linux/generic/backport-5.15/'
>      package/boot/uboot-mediatek/patches/100-07-mtd-nmbm-add-support-for-mtd.patch:+ struct mtd_oob_ops ops;
>      package/boot/uboot-mediatek/patches/100-07-mtd-nmbm-add-support-for-mtd.patch:+ struct mtd_oob_ops ops;
>      package/boot/uboot-mediatek/patches/100-11-env-add-support-for-NMBM-upper-MTD-layer.patch:+     struct mtd_oob_ops ops;

These patches are applied to U-Boot and not the kernel. The 
"fa4dc86e9808 kernel: backport MEMREAD ioctl"  change only changes he 
kernel.

> 
> Since the panic message includes mentions of a stack overflow, another
> idea would be to backport this upstream patch as well:
> 
>      https://lore.kernel.org/linux-mtd/20230417205654.1982368-1-arnd@kernel.org/
> 
> This patch has been reviewed, but it has not yet been merged anywhere.

Please send a patch to the openwrt mailing list or create a pull request 
on github.

hauke