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authorJiri Kosina <jkosina@suse.cz>2015-11-05 18:44:41 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-05 19:34:48 -0800
commit55537871ef666b4153fd1ef8782e4a13fee142cc (patch)
tree9e71e9e7db5b2f4f04e9d9c48d801717bb11eed7 /kernel/sysctl.c
parentee7fed540563b27e1028bec0b509921496c91bf9 (diff)
downloadlinux-sh-55537871ef666b4153fd1ef8782e4a13fee142cc.tar.gz
kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup
In many cases of hardlockup reports, it's actually not possible to know why it triggered, because the CPU that got stuck is usually waiting on a resource (with IRQs disabled) in posession of some other CPU is holding. IOW, we are often looking at the stacktrace of the victim and not the actual offender. Introduce sysctl / cmdline parameter that makes it possible to have hardlockup detector perform all-CPU backtrace. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Acked-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r--kernel/sysctl.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 96c856b04081..1a5faa3e1521 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -898,6 +898,15 @@ static struct ctl_table kern_table[] = {
.extra1 = &zero,
.extra2 = &one,
},
+ {
+ .procname = "hardlockup_all_cpu_backtrace",
+ .data = &sysctl_hardlockup_all_cpu_backtrace,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
#endif /* CONFIG_SMP */
#endif
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)