On Wed, 26 Nov 2014 18:05:41 +0300 Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > On Wed, Nov 26, 2014 at 09:43:06AM -0500, Steven Rostedt wrote: > > I highly doubt it's much of a speed up. And we do that by sacrificing > > that one byte of buffer, which would lose the printk if len does equal > > TRACE_BUF_SIZE. > > > > I don't see a bug here. What exactly are you trying to fix? > > Heh. vsnprintf() is going to put a NUL char at the end of the string > even if you don't plan to use it. :P > > Another option would be to just print truncated output. We could use > vscnprintf() and remove the off by one limit check. Yes, that is a better patch. The previous one wasn't really fixing anything. But printing truncated output is better than nothing. Want to send it officially? Thanks, -- Steve > > regards, > dan carpenter > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 42a822d..ab76b7b 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -2160,9 +2160,7 @@ __trace_array_vprintk(struct ring_buffer *buffer, > goto out; > } > > - len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args); > - if (len > TRACE_BUF_SIZE) > - goto out; > + len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args); > > local_save_flags(flags); > size = sizeof(*entry) + len + 1; > @@ -2173,8 +2171,7 @@ __trace_array_vprintk(struct ring_buffer *buffer, > entry = ring_buffer_event_data(event); > entry->ip = ip; > > - memcpy(&entry->buf, tbuffer, len); > - entry->buf[len] = '\0'; > + memcpy(&entry->buf, tbuffer, len + 1); > if (!call_filter_check_discard(call, entry, buffer, event)) { > __buffer_unlock_commit(buffer, event); > ftrace_trace_stack(buffer, flags, 6, pc); -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html