[PATCHv5] kexec.rules: create dedicated udev rules for ppc64 - kexec - Fedora mailing-lists

30 Apr 2019

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.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/mak...
 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

    