Commit e8c42d36 authored Apr 03, 2014 by Petr Mladek Committed by Linus Torvalds Apr 03, 2014

printk: add comment about tricky check for text buffer size

There is no check for potential "text_len" overflow.  It is not needed
because only valid level is detected.  It took me some time to
understand why.  It would deserve a comment ;-)

Signed-off-by: Petr Mladek <pmladek@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c64730b2

kernel/printk/printk.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1561,6 +1561,11 @@ asmlinkage int vprintk_emit(int facility, int level,
		case 'd': /* KERN_DEFAULT */
		lflags \|= LOG_PREFIX;
		}
		/*
		* No need to check length here because vscnprintf
		* put '\0' at the end of the string. Only valid and
		* newly printed level is detected.
		*/
		text_len -= end_of_header - text;
		text = (char *)end_of_header;
		}