linux-kernel - [PATCH] sched/vtime: Fix an unitialized variable warning

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Message-ID: <20200327214334.GF8015@zn.tnic>
Date:   Fri, 27 Mar 2020 22:43:34 +0100
From:   Borislav Petkov <bp@...e.de>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     x86-ml <x86@...nel.org>, lkml <linux-kernel@...r.kernel.org>
Subject: [PATCH] sched/vtime: Fix an unitialized variable warning

Hi dude,

right before I was going to send the trivial, shut-up-gcc variant, I
thought that maybe we should do this instead.

Thoughts?

---
Fix:

  kernel/sched/cputime.c: In function ‘kcpustat_field’:
  kernel/sched/cputime.c:1007:6: warning: ‘val’ may be used \
	  uninitialized in this function [-Wmaybe-uninitialized]
   1007 |  u64 val;
        | ^~~

because gcc can't see that val is used only when err is 0.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 kernel/sched/cputime.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index dac9104d126f..ff9435dee1df 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -1003,12 +1003,12 @@ u64 kcpustat_field(struct kernel_cpustat *kcpustat,
 		   enum cpu_usage_stat usage, int cpu)
 {
 	u64 *cpustat = kcpustat->cpustat;
+	u64 val = cpustat[usage];
 	struct rq *rq;
-	u64 val;
 	int err;
 
 	if (!vtime_accounting_enabled_cpu(cpu))
-		return cpustat[usage];
+		return val;
 
 	rq = cpu_rq(cpu);
 
-- 
2.21.0

-- 
Regards/Gruss,
    Boris.

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