Subject: + printk-add-comment-about-tricky-check-for-text-buffer-size.patch added to -mm tree
To: pmladek@xxxxxxx,fweisbec@xxxxxxxxx,jack@xxxxxxx,kay@xxxxxxxx,mhocko@xxxxxxx,rostedt@xxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 18 Feb 2014 13:03:44 -0800
The patch titled
Subject: printk: add comment about tricky check for text buffer size
has been added to the -mm tree. Its filename is
printk-add-comment-about-tricky-check-for-text-buffer-size.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/printk-add-comment-about-tricky-check-for-text-buffer-size.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/printk-add-comment-about-tricky-check-for-text-buffer-size.patch
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------------------------------------------------------
From: Petr Mladek <pmladek@xxxxxxx>
Subject: 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@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Kay Sievers <kay@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/printk/printk.c | 5 +++++
1 file changed, 5 insertions(+)
diff -puN kernel/printk/printk.c~printk-add-comment-about-tricky-check-for-text-buffer-size kernel/printk/printk.c
--- a/kernel/printk/printk.c~printk-add-comment-about-tricky-check-for-text-buffer-size
+++ a/kernel/printk/printk.c
@@ -1561,6 +1561,11 @@ asmlinkage int vprintk_emit(int facility
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;
}
_
Patches currently in -mm which might be from pmladek@xxxxxxx are
printk-remove-duplicated-check-for-log-level.patch
printk-remove-obsolete-check-for-log-level-c.patch
printk-add-comment-about-tricky-check-for-text-buffer-size.patch
printk-use-also-the-last-bytes-in-the-ring-buffer.patch
printk-do-not-compute-the-size-of-the-message-twice.patch
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