[RFC V2 PATCH 0/1] kexec: crash_kexec_post_notifiers boot option related fixes
hidehiro.kawai.ez at hitachi.com
Mon Aug 3 04:06:07 PDT 2015
Hello Eric and Vivek,
Do you have any comments?
(2015/07/24 10:16), Hidehiro Kawai wrote:
> This is a bugfix patch for crash_kexec_post_notifiers boot option
> which allows users to call panic notifiers and kmsg dumpers before
> This fixes one of the problems reported by Daniel Walker
> Problem 1:
> If crash_kexec_post_notifiers boot option is specified, some
> shutting down process which assume other cpus are still alive
> don't work properly.
> Problem 2 (addressed by this patch):
> If crash_kexec_post_notifiers boot option is specified, register
> information of other cpus are not saved to crash dumps.
> Following Vivek's opinion, this patch replaces smp_send_stop()
> in panic() with suitable version for crash_kexec which saves
> cpu states and other things like cleaning up VMX/SVM. Since this
> needs architecture specific implementation and it's not so trivial,
> this version only support for x86. So the problem 1, known to
> happen on MIPS/OCTEON, is not addressed now.
> To keep the modification impact low, this patch doesn't change
> the logic basically if crash_kexec_post_notifiers is not specified.
> Please note that crash_kexec() can be called directly without
> entering panic(). Stopping other cpus functionality is still
> needed in crash_kexec().
> Changes in V2:
> - Replace smp_send_stop() call with crash_kexec version which
> saves cpu states and does cleanups instead of changing execution
> - Drop a fix for Problem 1
> - Drop other patches because they aren't needed anymore
> V1: https://lkml.org/lkml/2015/7/10/316
> Hidehiro Kawai (1):
> panic/x86: Replace smp_send_stop() with crash_kexec version
> arch/x86/kernel/crash.c | 16 +++++++++++-----
> kernel/panic.c | 29 +++++++++++++++++++++++------
> 2 files changed, 34 insertions(+), 11 deletions(-)
Hitachi, Ltd. Research & Development Group
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