path: root/kernel
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authorPetr Mladek <pmladek@suse.cz>2014-04-03 14:48:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-03 16:21:07 -0700
commite8c42d36ab86cf45f88c3a0e344233b1032fbf3d (patch)
tree94fe60e04065bb06c1c83c68b8371dedc113cfc3 /kernel
parentc64730b26f08cccfbc8fcbf169c304b4bd71dcac (diff)
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>
Diffstat (limited to 'kernel')
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index db7a02e0524..012f3e40671 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -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;