12:57 a.m.
On Tue, Apr 30, 2019 at 11:55 AM Pingfan Liu <piliu(a)redhat.com> 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(a)redhat.com>
---
98-kexec.rules.ppc64 | 15 +++++++++++++++
kexec-tools.spec | 10 ++++++++--
2 files changed, 23 insertions(+), 2 deletions(-)
create mode 100644 98-kexec.rules.ppc64
diff --git a/98-kexec.rules.ppc64 b/98-kexec.rules.ppc64
new file mode 100644
index 0000000..1a91220
--- /dev/null
+++ b/98-kexec.rules.ppc64
@@ -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 kdump-udev-throttle will end up
+# doing nothing, but systemd-run will always generate extra logs for
+# each call, so trigger the kdump-udev-throttler 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 --no-block /usr/lib/udev/kdump-udev-throttler'"
+
+LABEL="kdump_reload_end"
diff --git a/kexec-tools.spec b/kexec-tools.spec
index a1e6686..3ebf9da 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/...
Source10: kexec-kdump-howto.txt
Source12: mkdumprd.8
-Source14: 98-kexec.rules
+Source13: 98-kexec.rules
+Source14: 98-kexec.rules.ppc64
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 %{SOURCE13} $RPM_BUILD_ROOT%{_udevrulesdir}/98-kexec.rules
+%endif
+%ifarch ppc64 ppc64le
install -m 644 %{SOURCE14} $RPM_BUILD_ROOT%{_udevrulesdir}/98-kexec.rules
-install -m 755 %{SOURCE28} $RPM_BUILD_ROOT%{_udevrulesdir}/../kdump-udev-throttler
%endif
install -m 644 %{SOURCE15} $RPM_BUILD_ROOT%{_mandir}/man5/kdump.conf.5
install -m 644 %{SOURCE16} $RPM_BUILD_ROOT%{_unitdir}/kdump.service
--
2.20.1
Double checked with x86, assume everything is tested on PPC:
Acked-by: Kairui Song <kasong(a)redhat.com>
--
Best Regards,
Kairui Song