As discussed with Dave offline, there is format issue with V2. Please drop it, and I will send out V3

On 04/28/2019 11:41 AM, Pingfan Liu wrote:

On powerpc, after hot add cpu and trigger crash on the hot-added cpu, the kdump kernel hangs after "I'm in purgatory".

The current udev rules expects the dtb to be rebuit on cpu add/remove event. But since powerpc does not follow the standard cpu hot add framework, it only ejects online/offline event to user space when cpu is hot added/removed, instead of add/remove event. Pingfan tried fixing that but it didn't please the maintainer as it breaks some old userspace tools.

Due to the failure of dtb's rebuilding, KDump kernel fails to get the 'boot_cpuid' and eventually fails to boot [see early_init_dt_scan_cpus() in arch/powerpc/kernel/prom.c file] if system crashes on hot-added CPU.

Work around it by changing udev rules on powerpc to onlne/offline.

As for offline message, it is even useless on powerpc, and can be dropped. See the explain: On powerpc, /sys/devices/system/cpu/cpuX nodes are present for all "possible", irrespective of whether a CPU is hot-added/removed. crash_notes are already built for all /sys/devices/system/cpu/cpuX nodes and these nodes are present for all "possible" CPUs (online/offline/could-be-hot-removed/could-be-hot-added)

Signed-off-by: Pingfan Liu piliu@redhat.com

98-kexec-ppc.rules | 15 +++++++++++++++ kexec-tools.spec | 10 ++++++++-- 2 files changed, 23 insertions(+), 2 deletions(-) create mode 100644 98-kexec-ppc.rules

diff --git a/98-kexec-ppc.rules b/98-kexec-ppc.rules new file mode 100644 index 0000000..9d783a0 --- /dev/null +++ b/98-kexec-ppc.rules @@ -0,0 +1,15 @@ +SUBSYSTEM=="cpu", ACTION=="online", GOTO="kdump_reload" +SUBSYSTEM=="memory", ACTION=="online", GOTO="kdump_reload" +SUBSYSTEM=="memory", ACTION=="offline", GOTO="kdump_reload"

+GOTO="kdump_reload_end"

+LABEL="kdump_reload"

+# If kdump is not loaded, calling "kdumpctl reload" will end up +# doing nothing, but it and systemd-run will always generate +# extra logs for each call, so trigger the "kdumpctl reload" +# only if kdump service is active to avoid unnecessary logs +RUN+="/bin/sh -c '/usr/bin/systemctl is-active kdump.service || exit 0; /usr/bin/systemd-run --quiet /usr/bin/kdumpctl reload'"

+LABEL="kdump_reload_end" diff --git a/kexec-tools.spec b/kexec-tools.spec index a1e6686..2bc983c 100644 --- a/kexec-tools.spec +++ b/kexec-tools.spec @@ -18,7 +18,8 @@ Source8: kdump.conf Source9: http://downloads.sourceforge.net/project/makedumpfile/makedumpfile/1.6.5/mak... Source10: kexec-kdump-howto.txt Source12: mkdumprd.8 -Source14: 98-kexec.rules +Source13: 98-kexec.rules +Source14: 98-kexec-ppc.rules Source15: kdump.conf.5 Source16: kdump.service Source18: kdump.sysconfig.s390x @@ -169,10 +170,15 @@ install -m 644 %{SOURCE25} $RPM_BUILD_ROOT%{_mandir}/man8/kdumpctl.8 install -m 755 %{SOURCE20} $RPM_BUILD_ROOT%{_prefix}/lib/kdump/kdump-lib.sh install -m 755 %{SOURCE23} $RPM_BUILD_ROOT%{_prefix}/lib/kdump/kdump-lib-initramfs.sh %ifnarch s390x +install -m 755 %{SOURCE28} $RPM_BUILD_ROOT%{_udevrulesdir}/../kdump-udev-throttler +%endif +%ifnarch s390x ppc64 ppc64le # For s390x the ELF header is created in the kdump kernel and therefore kexec # udev rules are not required install -m 644 %{SOURCE14} $RPM_BUILD_ROOT%{_udevrulesdir}/98-kexec.rules -install -m 755 %{SOURCE28} $RPM_BUILD_ROOT%{_udevrulesdir}/../kdump-udev-throttler +%endif +%ifarch ppc64 ppc64le +install -m 644 %{SOURCE14} $RPM_BUILD_ROOT%{_udevrulesdir}/98-kexec-ppc.rules %endif install -m 644 %{SOURCE15} $RPM_BUILD_ROOT%{_mandir}/man5/kdump.conf.5 install -m 644 %{SOURCE16} $RPM_BUILD_ROOT%{_unitdir}/kdump.service