linux-stable/Documentation/clearing-warn-once.txt


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.
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> 2017-11-17 23:27:03 +00:00
			`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.`