Hi Yulong,
On Fri, Mar 1, 2024 at 4:25 PM tang yulong <1637403063@xxxxxx> wrote:
>
> > Hi Yulong,
> >
> > Thanks for your patch!
> >
> > On Mon, Feb 26, 2024 at 3:20 PM Yulong TANG 汤玉龙 <yulong.tang(a)nio.com> wrote:
> >
> > I have no objection to the lzo-rle decompression feature for crash.
> > However I have some concern of your patch:
> >
> > The patch you attached is a "lzorle_decompress_safe" implementation
> > which is copied from kernel source code. One of the drawbacks of
> > copying kernel source code is, kernel is constantly evolving, the code
> > you copied here today maybe updated someday later, and in support of
> > different kernel versions, we need to keep a bunch of
> > switch(kernel_version) and case code to keep the compatibility, which
> > is what we are trying to avoid.
> >
> > In addition, the code you copied has deliberately deleted the "if
> > defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)" part, which may also
> > cause some problem, and as far as I know, there is no good way in
> > crash to determine the kernel config status, please feel free to
> > correct me if I'm wrong.
>
> Hi Tao,
>
> I discovered that there seems to be an array called ikconfig_all in kernel.c which records the kernel config status, and there is an API called get_kernel_config(char *conf_name, char **str) for obtaining kernel configuration. This might help solve the second problem you raised.
> For example, adding a line:
> #define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS get_kernel_config("CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS", NULL);
>
OK, thanks for the clarification, sounds workable. Then what do you
think if we keep the "if
defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)" related code of the
copied kernel code, but change the "if defined" macro into a runtime
check like "if get_kernel_config("CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS",
NULL)) == IKCONFIG_Y". So the code can be chosen whether to execute
depending on the config status.
Thanks,
Tao Liu
> Thanks,
> Yulong
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