lkml.org 
[lkml]   [2014]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] tracing: off by one in __trace_array_vprintk()
On Wed, 26 Nov 2014 17:06:21 +0300
Dan Carpenter <dan.carpenter@oracle.com> wrote:

> This check says "goto out;" if we had to truncate the string.
>
> The "tbuffer" buffer has TRACE_BUF_SIZE bytes. The vsnprintf() function
> returns the number of characters (not counting the NUL char) which would
> have been printed if there were space. If we we tried to print
> TRACE_BUF_SIZE characters, the last character would have been truncated
> to make space for the NUL character so we should "goto out;".
>

Oh, and the NUL character is never copied. We copy the string into the
buffer with:

memcpy(&entry->buf, tbuffer, len);

Where len does not include NUL, and why we add it ourselves.

-- Steve


\
 
 \ /
  Last update: 2014-11-26 16:01    [W:0.060 / U:0.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site