path: root/Documentation/kernel-parameters.txt
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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 /Documentation/kernel-parameters.txt
parentee7fed540563b27e1028bec0b509921496c91bf9 (diff)
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 'Documentation/kernel-parameters.txt')
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6263a2da3e2f..0231f4508abe 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1269,6 +1269,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
Default: 1024
+ hardlockup_all_cpu_backtrace=
+ [KNL] Should the hard-lockup detector generate
+ backtraces on all cpus.
+ Format: <integer>
hashdist= [KNL,NUMA] Large hashes allocated during boot
are distributed across NUMA nodes. Defaults on
for 64-bit NUMA, off otherwise.

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