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| author | Jiri Kosina <jkosina@suse.cz> | 2015-11-05 18:44:41 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-05 19:34:48 -0800 |
| commit | 55537871ef666b4153fd1ef8782e4a13fee142cc (patch) | |
| tree | 9e71e9e7db5b2f4f04e9d9c48d801717bb11eed7 /Documentation/sysctl | |
| parent | ee7fed540563b27e1028bec0b509921496c91bf9 (diff) | |
| download | linux-stable-55537871ef666b4153fd1ef8782e4a13fee142cc.tar.gz linux-stable-55537871ef666b4153fd1ef8782e4a13fee142cc.tar.bz2 linux-stable-55537871ef666b4153fd1ef8782e4a13fee142cc.zip | |
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/sysctl')
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 6fccb69c03e7..af70d1541d3a 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -33,6 +33,7 @@ show up in /proc/sys/kernel: - domainname - hostname - hotplug +- hardlockup_all_cpu_backtrace - hung_task_panic - hung_task_check_count - hung_task_timeout_secs @@ -293,6 +294,17 @@ domain names are in general different. For a detailed discussion see the hostname(1) man page. ============================================================== +hardlockup_all_cpu_backtrace: + +This value controls the hard lockup detector behavior when a hard +lockup condition is detected as to whether or not to gather further +debug information. If enabled, arch-specific all-CPU stack dumping +will be initiated. + +0: do nothing. This is the default behavior. + +1: on detection capture more debug information. +============================================================== hotplug: |