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

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/20220813031753.309... >>>> 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/20220813031753.309... >> 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, Kazu