Re: [PATCH V2] kernel/hung_task.c: Introduce sysctl to print all traces when a hung task is detected
From: Randy Dunlap <rdunlap@infradead.org>
Date: 2020-03-23 23:39:35
Also in:
cocci, linux-doc, linux-fsdevel, lkml
Hi, On 3/23/20 2:46 PM, Guilherme G. Piccoli wrote:
.../admin-guide/kernel-parameters.txt | 6 ++++ Documentation/admin-guide/sysctl/kernel.rst | 15 ++++++++++ include/linux/sched/sysctl.h | 7 +++++ kernel/hung_task.c | 30 +++++++++++++++++-- kernel/sysctl.c | 11 +++++++ 5 files changed, 67 insertions(+), 2 deletions(-)
admin-guide/kernel-parameters.txt predominantly uses "CPUs" for plural CPUs when not part of a cmdline keyword etc., so please adjust below:
quoted hunk ↗ jump to hunk
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c07815d230bc..7a14caac6c94 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt@@ -1453,6 +1453,12 @@ x86-64 are 2M (when the CPU supports "pse") and 1G (when the CPU supports the "pdpe1gb" cpuinfo flag). + hung_task_all_cpu_backtrace= + [KNL] Should kernel generate backtraces on all cpus
CPUs
quoted hunk ↗ jump to hunk
+ when a hung task is detected. Defaults to 0 and can + be controlled by hung_task_all_cpu_backtrace sysctl. + Format: <integer> + hung_task_panic= [KNL] Should the hung task detector generate panics. Format: <integer>diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index def074807cee..8b4ff69d2348 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst@@ -40,6 +40,7 @@ show up in /proc/sys/kernel: - hotplug - hardlockup_all_cpu_backtrace - hardlockup_panic +- hung_task_all_cpu_backtrace - hung_task_panic - hung_task_check_count - hung_task_timeout_secs@@ -338,6 +339,20 @@ Path for the hotplug policy agent. Default value is "/sbin/hotplug". +hung_task_all_cpu_backtrace: +================ + +If this option is set, the kernel will send an NMI to all CPUs to dump +their backtraces when a hung task is detected. This file shows up if +CONFIG_DETECT_HUNG_TASK and CONFIG_SMP are enabled. + +0: Won't show all CPUs backtraces when a hung task is detected. +This is the default behavior. + +1: Will non-maskably interrupt all CPUs and dump their backtraces when +a hung task is detected. + + hung_task_panic: ================
thanks. -- ~Randy