Re: [PATCH 07/18 v3] tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

[Steven Rostedt]

On Fri, 17 Apr 2015 09:29:02 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Fri, 17 Apr 2015 10:44:42 +0300
> Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx> wrote:
> 
>  
> > And kasan is not needed to debug this further.
> > Just stick WARN_ON(ptr > call->print_fmt + strlen(call->print_fmt)) into the 'for' loop in update_event_printk().
> 
> Thanks, although I think I found the bug with just inspection. I put in
> WARN_ON(*ptr) at various locations to see if it triggers.

Yep, that's the issue.

Can you guys test this patch please:

-- Steve

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 39bcfc3f071d..97d454a4dbfb 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1753,6 +1753,8 @@ static void update_event_printk(struct ftrace_event_call *call,
 				ptr++;
 				/* Check for alpha chars like ULL */
 			} while (isalnum(*ptr));
+			if (!*ptr)
+				break;
 			/*
 			 * A number must have some kind of delimiter after
 			 * it, and we can ignore that too.
@@ -1779,12 +1781,16 @@ static void update_event_printk(struct ftrace_event_call *call,
 			do {
 				ptr++;
 			} while (isalnum(*ptr) || *ptr == '_');
+			if (!*ptr)
+				break;
 			/*
 			 * If what comes after this variable is a '.' or
 			 * '->' then we can continue to ignore that string.
 			 */
 			if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
 				ptr += *ptr == '.' ? 1 : 2;
+				if (!*ptr)
+					break;
 				goto skip_more;
 			}
 			/*
--
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