On Tue, Oct 23, 2012 at 10:44:50PM +0900, Namhyung Kim wrote:
> This was found during chasing down the header output regression.
> The strbuf_addf() was checking buffer length with a result of
> vscnprintf() which cannot be greater than that of strbuf_avail().
>
> Since numa topology and pmu mapping info in header were converted
> to use strbuf, it sometimes caused uninteresting behaviors with the
> broken strbuf.
>
> Fix it by using vsnprintf() which returns desired output string
> length regardless of the available buffer size and grow the buffer
> if needed.
>
> Reported-by: Andrew Jones <drjo...@redhat.com>
> Signed-off-by: Namhyung Kim <namhy...@kernel.org>
> ---
> tools/perf/util/strbuf.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/strbuf.c b/tools/perf/util/strbuf.c
> index 2eeb51baf077..cfa906882e2c 100644
> --- a/tools/perf/util/strbuf.c
> +++ b/tools/perf/util/strbuf.c
> @@ -90,17 +90,17 @@ void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
> if (!strbuf_avail(sb))
> strbuf_grow(sb, 64);
> va_start(ap, fmt);
> - len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
> + len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
> va_end(ap);
> if (len < 0)
> - die("your vscnprintf is broken");
> + die("your vsnprintf is broken");
> if (len > strbuf_avail(sb)) {
> strbuf_grow(sb, len);
> va_start(ap, fmt);
> - len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt,
> ap);
> + len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt,
> ap);
> va_end(ap);
> if (len > strbuf_avail(sb)) {
> - die("this should not happen, your snprintf is broken");
> + die("this should not happen, your vsnprintf is broken");
> }
> }
> strbuf_setlen(sb, sb->len + len);
> --
> 1.7.9.2
>
Tested-by: Andrew Jones <drjo...@redhat.com>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
