Re: [PATCH V3 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support

[Xianting Tian]

在 2022/10/20 上午9:35, HAGIO KAZUHITO(萩尾 一仁) 写道:
> On 2022/10/19 12:17, Xianting Tian wrote:
>
> > > > > > > > +    if (IS_ENABLED(CONFIG_64BIT)) {
> > > > > > > > +#ifdef CONFIG_KASAN
> > > > > > > > +        vmcoreinfo_append_str("NUMBER(KASAN_SHADOW_START)=0x%lx\n", KASAN_SHADOW_START);
> > > > > > > > +        vmcoreinfo_append_str("NUMBER(KASAN_SHADOW_END)=0x%lx\n", KASAN_SHADOW_END);
> > > > > > > > +#endif
> > > > > > > > +        vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR);
> > > > > > > > +        vmcoreinfo_append_str("NUMBER(ADDRESS_SPACE_END)=0x%lx\n", ADDRESS_SPACE_END);
> > > > > > > Seems this is the firsr ARCH where kasan and kernel link/bpf space are
> > > > > > > added to dump and analyze. Just curious, have you got code change to
> > > > > > > make use of them to do dumping and analyze?
> > > > > > KASAN_SHADOW_START is not used, KERNEL_LINK_ADDR is used in the crash patch set:
> > > > > > https://patchwork.kernel.org/project/linux-riscv/cover/20220813031753.3097720-1-xianting.tian@xxxxxxxxxxxxxxxxx/
> > > > > Oh, I would say please no. Sometime we got tons of objection when adding an
> > > > > necessary one, we definitely should not add one for possible future
> > > > > use.
> > > > >
> > > > > For this kind of newly added one, we need get ack from
> > > > > makedumpfile/crash utility maintainer so that we know they are necessary
> > > > > to have. At least they don't oppose.
> > > > Hi Kazu, Li Jiang
> > > >
> > > > Could you help comment whether we need KASAN_SHADOW_START and KERNEL_LINK_ADDR area export for vmcore from crash point of view？
> > > >
> > > > In my crash patch set, I don't use KASAN_SHADOW_START,
> > > > And only get the value of KERNEL_LINK_ADDR, not realy use it.
> > > > https://patchwork.kernel.org/project/linux-riscv/cover/20220813031753.3097720-1-xianting.tian@xxxxxxxxxxxxxxxxx/
> > > In your crash patch set, KERNEL_LINK_ADDR is used in VTOP() and looks
> > > necessary to me.
> > >
> > > The others (KASAN_SHADOW_START, KASAN_SHADOW_END and ADDRESS_SPACE_END)
> > > are not currently used.  It may be better to add them when they are
> > > really used.
> > I am very sorry, I missed it , KERNEL_LINK_ADDR is used indeed.
> >
> > KASAN_SHADOW_START is not used, so I don't need to send crash patch set> again. only need to remove KASAN_SHADOW_END in kernel patch set.
> I see that your v4 kernel patch set does not have ADDRESS_SPACE_END,
> so it seems there would be need to change this part and related ones
> at crash side.
>
>           if ((string = pc->read_vmcoreinfo("NUMBER(ADDRESS_SPACE_END)"))) {
>                   ms->address_space_end = htol(string, QUIET, NULL);
>                   free(string);
>           } else
>                   goto error;
> ...
> error:
>           error(FATAL, "cannot get vm layout\n");

thanks,

I just send V4 of crash patch set, the issue is also fixed in V4.

> Thanks,
> Kazu