> On 14-Sep-2023, at 2:52 PM, Aditya Gupta <adityag@xxxxxxxxxxxxx> wrote: > > Currently 'makedumpfile' fails to collect vmcore on upstream kernel, > with the errors: > > readpage_elf: Attempt to read non-existent page at 0x4000000000000000. > readmem: type_addr: 0, addr:0, size:8 > get_vmemmap_list_info: Can't get vmemmap region addresses > get_machdep_info_ppc64: Can't get vmemmap list info. > > This occurs since makedumpfile depends on 'vmemmap_list' for translating > vmemmap addresses. But with below commit in Linux, vmemmap_list can be > empty, in case of Radix MMU on PowerPC64 > > 368a0590d954: (powerpc/book3s64/vmemmap: switch radix to use a > different vmemmap handling function) > > In case vmemmap_list is empty, then it's head is NULL, which causes > makedumpfile to fail with above error. > > Since with above commit, 'vmemmap_list' is not populated (when MMU is > Radix MMU), kernel populates corresponding page table entries in kernel > page table. Hence, instead of depending on 'vmemmap_list' for address > translation for vmemmap addresses, do a kernel pagetable walk. > > And since the pte can also be introduced at higher levels in the page > table, such as at PMD level, add hugepage support, by checking for > PAGE_PTE flag > > Reported-by: Sachin Sant <sachinp@xxxxxxxxxxxxx> > Signed-off-by: Aditya Gupta <adityag@xxxxxxxxxxxxx> > — Thanks for the fix. With this (and the corresponding kernel) fix applied, I am able to capture crash dump. Tested-by: Sachin Sant <sachinp@xxxxxxxxxxxxx> - Sachin _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
