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From: Steven Rostedt <rostedt@goodmis.org>
To: shuah.kh@samsung.com
Cc: len.brown@intel.com, pavel@ucw.cz, rjw@rjwysocki.net,
	gregkh@linuxfoundation.org, anton@enomsg.org,
	dwmw2@infradead.org, fweisbec@gmail.com, mingo@redhat.com,
	keun-o.park@windriver.com, paul.gortmaker@windriver.com,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	shuahkhan@gmail.com, stable@vger.kernel.org
Subject: Re: [PATCH 2/2] PM: Fix Oops from NULL pointer dereference in wakeup_source_activate
Date: Wed, 20 Nov 2013 21:26:56 -0500	[thread overview]
Message-ID: <20131120212656.1df4515e@gandalf.local.home> (raw)
In-Reply-To: <528D6972.9010702@samsung.com>

On Wed, 20 Nov 2013 19:01:22 -0700
Shuah Khan <shuah.kh@samsung.com> wrote:

> On 11/20/2013 06:40 PM, Shuah Khan wrote:

> > ---
> >   include/trace/events/power.h | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/trace/events/power.h b/include/trace/events/power.h
> > index cda100d..5ba545a 100644
> > --- a/include/trace/events/power.h
> > +++ b/include/trace/events/power.h
> > @@ -110,12 +110,14 @@ DECLARE_EVENT_CLASS(wakeup_source,
> >   	TP_ARGS(name, state),
> >
> >   	TP_STRUCT__entry(
> > -		__string(       name,           name            )
> > +		__string(name,  name ? name : "(no name)")
> >   		__field(        u64,            state           )
> >   	),
> >
> >   	TP_fast_assign(
> > -		__assign_str(name, name);
> > +		const char *tname = name ? name : "(no name)";
> > +
> > +		__assign_str(name, tname);
> >   		__entry->state = state;
> >   	),
> >
> >
> 
> Adding tracing maintainers.

Thanks!

This is one solution, but what about just making the tracing facility a
bit more robust for everyone. Following what glibc printf() does when
it is passed a NULL, does this patch fix it too?

-- Steve

(haven't even compile tested this)

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 52594b2..bdac88c 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -372,7 +372,8 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call)	\
 	__data_size += (len) * sizeof(type);
 
 #undef __string
-#define __string(item, src) __dynamic_array(char, item, strlen(src) + 1)
+#define __string(item, src) __dynamic_array(char, item,			\
+				    strlen((src) ? (src) : "(null)") + 1)
 
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
@@ -501,7 +502,7 @@ static inline notrace int ftrace_get_offsets_##call(			\
 
 #undef __assign_str
 #define __assign_str(dst, src)						\
-	strcpy(__get_str(dst), src);
+	strcpy(__get_str(dst), (src) ? (src) : "(null)");
 
 #undef TP_fast_assign
 #define TP_fast_assign(args...) args


  reply	other threads:[~2013-11-21  2:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-21  1:40 [PATCH 0/2] power_supply: Fix Oops from NULL pointer dereference from wakeup_source_activate Shuah Khan
2013-11-21  1:40 ` [PATCH 1/2] " Shuah Khan
2013-11-21  1:40 ` [PATCH 2/2] PM: Fix Oops from NULL pointer dereference in wakeup_source_activate Shuah Khan
2013-11-21  2:01   ` Shuah Khan
2013-11-21  2:26     ` Steven Rostedt [this message]
2013-11-21 18:02       ` Shuah Khan

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