From 808bf29b9195c52239b9aaeda7c6082a0ddf07c6 Mon Sep 17 00:00:00 2001 From: Alexander Sverdlin Date: Wed, 21 Sep 2011 09:51:40 +0200 Subject: [PATCH] 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 Signed-off-by: Linus Torvalds --- init/main.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/init/main.c b/init/main.c index 9c51ee7adf3d..2a9b88aa5e76 100644 --- a/init/main.c +++ b/init/main.c @@ -209,8 +209,19 @@ early_param("quiet", quiet_kernel); static int __init loglevel(char *str) { - get_option(&str, &console_loglevel); - return 0; + 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);