Commit 808bf29b authored Sep 21, 2011 by Alexander Sverdlin Committed by Linus Torvalds Sep 21, 2011

init: carefully handle loglevel option on kernel cmdline.



When a malformed loglevel value (for example "${abc}") is passed on the
kernel cmdline, the loglevel itself is being set to 0.

That then suppresses all following messages, including all the errors
and crashes caused by other malformed cmdline options.  This could make
debugging process quite tricky.

This patch leaves the previous value of loglevel if the new value is
incorrect and reports an error code in this case.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@sysgo.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 32ef4384

init/main.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -209,10 +209,21 @@ early_param("quiet", quiet_kernel);

		static int __init loglevel(char *str)
		{
		get_option(&str, &console_loglevel);
		int newlevel;

		/*
		* Only update loglevel value when a correct setting was passed,
		* to prevent blind crashes (when loglevel being set to 0) that
		* are quite hard to debug
		*/
		if (get_option(&str, &newlevel)) {
		console_loglevel = newlevel;
		return 0;
		}

		return -EINVAL;
		}

		early_param("loglevel", loglevel);

		/*

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