qemu can make elf vmcore without kdump in kernel. So kernel may not have "kexec_crash_image" symbol. Without this patch, kdump_backup_region_init() stops main_loop with error. --- netdump.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff -puN netdump.c~check-kexec_crash_image netdump.c --- crash-64/netdump.c~check-kexec_crash_image 2016-03-29 19:38:08.556253626 +0900 +++ crash-64-hirofumi/netdump.c 2016-03-29 19:38:08.557253630 +0900 @@ -4458,11 +4458,14 @@ kdump_backup_region_init(void) } else return; - if (!readmem(symbol_value("kexec_crash_image"), KVADDR, - &kexec_crash_image_p, sizeof(ulong), - "kexec backup region: kexec_crash_image", - QUIET|RETURN_ON_ERROR)) - goto error; + if (symbol_exists("kexec_crash_image")) { + if (!readmem(symbol_value("kexec_crash_image"), KVADDR, + &kexec_crash_image_p, sizeof(ulong), + "kexec backup region: kexec_crash_image", + QUIET|RETURN_ON_ERROR)) + goto error; + } else + kexec_crash_image_p = 0; if (!kexec_crash_image_p) { if (CRASHDEBUG(1)) _ -- OGAWA Hirofumi <hirofumi(a)mail.parknet.co.jp&gt;