kernel 3.2.2 can't dump memory after crashes

915086731 · 12-11-2017, 09:48 PM

I have a debian 7.9(kernel 3.2.0-4-amd64) runing on Virtualbox. It's Kdump works normally after system crash by inputting "echo c > /proc/sysrq-trigger".

However, The kernel 3.2.2, which is compiled and installed by myself, hangs forever when I trigger a system crash event. It seems that my kernel can't works with kdump-tools. But I can use "kexec -l ..." & "kexec -e " to manually boot into my kernel. Sometimes my kernel(3.2.2) can boot into official kernel(3.2.0-4-amd64) after system crashes.

Does anyone be familiar with kdump and kexec ?

smallpond · 12-14-2017, 11:48 AM

What are the DUMP config settings in your kernel? For mine:

Code:

 grep DUMP /boot/config-`uname -r`
CONFIG_HAVE_PERF_USER_STACK_DUMP=y
CONFIG_CRASH_DUMP=y
CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS=y
CONFIG_COREDUMP=y
CONFIG_SCSI_IPR_DUMP=y
# CONFIG_X86_PTDUMP is not set

915086731 · 12-15-2017, 12:34 AM

The official kernel 3.2.0-4-amd64 can dump normally, the following is the dump setting:

Code:

linux-3.2.1$ grep DUMP /boot/config-3.2.0-4-amd64
CONFIG_CRASH_DUMP=y
CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS=y
# CONFIG_SCSI_IPR_DUMP is not set
CONFIG_JOYSTICK_JOYDUMP=m
# CONFIG_LINE6_USB_DUMP_PCM is not set
# CONFIG_X86_PTDUMP is not set

While my kernel 3.2.1 can't work with kdump:

Code:

linux-3.2.1$ grep DUMP /boot/config-3.2.1 
CONFIG_CRASH_DUMP=y
CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS=y
# CONFIG_SCSI_IPR_DUMP is not set
CONFIG_JOYSTICK_JOYDUMP=m
# CONFIG_LINE6_USB_DUMP_CTRL is not set
# CONFIG_LINE6_USB_DUMP_MIDI is not set
# CONFIG_LINE6_USB_DUMP_PCM is not set
# CONFIG_X86_PTDUMP is not set

I can't see anything different that's critical to support kdump between the two setting.

915086731 · 12-15-2017, 12:38 AM

Quote:

Originally Posted by smallpond

What are the DUMP config settings in your kernel? For mine:

Code:

 grep DUMP /boot/config-`uname -r`
CONFIG_HAVE_PERF_USER_STACK_DUMP=y
CONFIG_CRASH_DUMP=y
CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS=y
CONFIG_COREDUMP=y
CONFIG_SCSI_IPR_DUMP=y
# CONFIG_X86_PTDUMP is not set

My kernel fails with kdump, but I have not way to trace what's happening to kdump, no log and no print to me about the progress of kdump.