From: "Ken'ichi Ohmichi" Fix the problem that makedumpfile sometimes fails on x86_64 machine. This patch adds the symbol "phys_base" to a vmcoreinfo data. The vmcoreinfo data has the minimum debugging information only for dump filtering. makedumpfile (dump filtering command) gets it to distinguish unnecessary pages, and makedumpfile creates a small dumpfile. On x86_64 kernel which compiled with CONFIG_PHYSICAL_START=0x0 and CONFIG_RELOCATABLE=y, makedumpfile fails like the following: # makedumpfile -d31 /proc/vmcore dumpfile The kernel version is not supported. The created dumpfile may be incomplete. _exclude_free_page: Can't get next online node. makedumpfile Failed. # The cause is the lack of the symbol "phys_base" in a vmcoreinfo data. If the symbol "phys_base" does not exist, makedumpfile considers an x86_64 kernel as non relocatable. As the result, makedumpfile misunderstands the physical address where the kernel is loaded, and it cannot translate a kernel virtual address to physical address correctly. To fix this proble, the attached patch which adds the symbol "phys_base" to a vmcoreinfo data. Signed-off-by: Ken'ichi Ohmichi Cc: "Eric W. Biederman" Cc: Signed-off-by: Andrew Morton --- arch/x86/kernel/machine_kexec_64.c | 1 + 1 file changed, 1 insertion(+) diff -puN arch/x86/kernel/machine_kexec_64.c~vmcoreinfo-add-the-symbol-phys_base arch/x86/kernel/machine_kexec_64.c --- a/arch/x86/kernel/machine_kexec_64.c~vmcoreinfo-add-the-symbol-phys_base +++ a/arch/x86/kernel/machine_kexec_64.c @@ -233,6 +233,7 @@ NORET_TYPE void machine_kexec(struct kim void arch_crash_save_vmcoreinfo(void) { + VMCOREINFO_SYMBOL(phys_base); VMCOREINFO_SYMBOL(init_level4_pgt); #ifdef CONFIG_NUMA _