linux-kernel - [PATCH 2/3] selftests: timers: Fix uninitialized variable warning in ksft_min_kernel

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Message-ID: <20240410232637.4135564-2-jstultz@google.com>
Date: Wed, 10 Apr 2024 16:26:29 -0700
From: John Stultz <jstultz@...gle.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: John Stultz <jstultz@...gle.com>, Shuah Khan <shuah@...nel.org>, 
	Anna-Maria Behnsen <anna-maria@...utronix.de>, Frederic Weisbecker <frederic@...nel.org>, 
	Thomas Gleixner <tglx@...utronix.de>, Stephen Boyd <sboyd@...nel.org>, 
	Nathan Chancellor <nathan@...nel.org>, Nick Desaulniers <ndesaulniers@...gle.com>, 
	Bill Wendling <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>, 
	Oleg Nesterov <oleg@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	Edward Liaw <edliaw@...gle.com>, Carlos Llamas <cmllamas@...gle.com>, kernel-team@...roid.com, 
	linux-kselftest@...r.kernel.org
Subject: [PATCH 2/3] selftests: timers: Fix uninitialized variable warning in ksft_min_kernel_version

Building with clang, I see the following warning:

In file included from posix_timers.c:17:
/../kselftest.h:398:6: warning: variable 'major' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
        if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)
            ^~~~~~~~~~~~
/../kselftest.h:401:9: note: uninitialized use occurs here
        return major > min_major || (major == min_major && minor >= min_minor);
               ^~~~~

This is a bit of a red-herring as if the uname() call did fail,
we would hit ksft_exit_fail_msg() which should exit.

But to make clang happpy, lets initialize the major/minor values
to zero.

Cc: Shuah Khan <shuah@...nel.org>
Cc: Anna-Maria Behnsen <anna-maria@...utronix.de>
Cc: Frederic Weisbecker <frederic@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Stephen Boyd <sboyd@...nel.org>
Cc: Nathan Chancellor <nathan@...nel.org>
Cc: Nick Desaulniers <ndesaulniers@...gle.com>
Cc: Bill Wendling <morbo@...gle.com>
Cc: Justin Stitt <justinstitt@...gle.com>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Edward Liaw <edliaw@...gle.com>
Cc: Carlos Llamas <cmllamas@...gle.com>
Cc: kernel-team@...roid.com
Cc: linux-kselftest@...r.kernel.org
Fixes: 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()")
Signed-off-by: John Stultz <jstultz@...gle.com>
---
 tools/testing/selftests/kselftest.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index 973b18e156b2..12e2f3ab8b13 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -392,7 +392,7 @@ static inline __printf(1, 2) int ksft_exit_skip(const char *msg, ...)
 static inline int ksft_min_kernel_version(unsigned int min_major,
 					  unsigned int min_minor)
 {
-	unsigned int major, minor;
+	unsigned int major = 0, minor = 0;
 	struct utsname info;
 
 	if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)
-- 
2.44.0.478.gd926399ef9-goog