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| author | Andi Kleen <ak@linux.intel.com> | 2017-11-17 15:27:03 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-17 16:10:00 -0800 |
| commit | b1fca27d384e8418aac84b39f6f5179aecc1b64f (patch) | |
| tree | e08be97de59a1cbb16df46273aadef161358b8ba /Documentation/clearing-warn-once.txt | |
| parent | fb6cc4ac15c354fa1eb449f50a0dfe5f4bf0d42a (diff) | |
| download | lwn-b1fca27d384e8418aac84b39f6f5179aecc1b64f.tar.gz lwn-b1fca27d384e8418aac84b39f6f5179aecc1b64f.zip | |
kernel debug: support resetting WARN*_ONCE
I like _ONCE warnings because it's guaranteed that they don't flood the
log.
During testing I find it useful to reset the state of the once warnings,
so that I can rerun tests and see if they trigger again, or can
guarantee that a test run always hits the same warnings.
This patch adds a debugfs interface to reset all the _ONCE warnings so
that they appear again:
echo 1 > /sys/kernel/debug/clear_warn_once
This is implemented by putting all the warning booleans into a special
section, and clearing it.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20171017221455.6740-1-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/clearing-warn-once.txt')
| -rw-r--r-- | Documentation/clearing-warn-once.txt | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/clearing-warn-once.txt b/Documentation/clearing-warn-once.txt new file mode 100644 index 000000000000..5b1f5d547be1 --- /dev/null +++ b/Documentation/clearing-warn-once.txt @@ -0,0 +1,7 @@ + +WARN_ONCE / WARN_ON_ONCE only print a warning once. + +echo 1 > /sys/kernel/debug/clear_warn_once + +clears the state and allows the warnings to print once again. +This can be useful after test suite runs to reproduce problems. |