From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
stable@vger.kernel.org, kbuild test robot <lkp@intel.com>
Subject: [PATCH 6/7] tracing: Quiet gcc warning about maybe unused link variable
Date: Thu, 26 Jul 2018 19:06:13 -0400 [thread overview]
Message-ID: <20180726230652.286536726@goodmis.org> (raw)
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Commit 57ea2a34adf4 ("tracing/kprobes: Fix trace_probe flags on
enable_trace_kprobe() failure") added an if statement that depends on another
if statement that gcc doesn't see will initialize the "link" variable and
gives the warning:
"warning: 'link' may be used uninitialized in this function"
It is really a false positive, but to quiet the warning, and also to make
sure that it never actually is used uninitialized, initialize the "link"
variable to NULL and add an if (!WARN_ON_ONCE(!link)) where the compiler
thinks it could be used uninitialized.
Cc: stable@vger.kernel.org
Fixes: 57ea2a34adf4 ("tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_kprobe.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 27ace4513c43..6b71860f3998 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -400,7 +400,7 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
static int
enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
{
- struct event_file_link *link;
+ struct event_file_link *link = NULL;
int ret = 0;
if (file) {
@@ -426,7 +426,9 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
if (ret) {
if (file) {
- list_del_rcu(&link->list);
+ /* Notice the if is true on not WARN() */
+ if (!WARN_ON_ONCE(!link))
+ list_del_rcu(&link->list);
kfree(link);
tk->tp.flags &= ~TP_FLAG_TRACE;
} else {
--
2.17.1
reply other threads:[~2018-07-26 23:07 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180726230652.286536726@goodmis.org \
--to=rostedt@goodmis.org \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@intel.com \
--cc=mingo@kernel.org \
--cc=stable@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox