linux-kernel - [PATCH] padata: fix uninitialized return value in padata

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Message-Id: <20200210181100.1288437-1-daniel.m.jordan@oracle.com>
Date:   Mon, 10 Feb 2020 13:11:00 -0500
From:   Daniel Jordan <daniel.m.jordan@...cle.com>
To:     Herbert Xu <herbert@...dor.apana.org.au>,
        Steffen Klassert <steffen.klassert@...unet.com>
Cc:     Daniel Jordan <daniel.m.jordan@...cle.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] padata: fix uninitialized return value in padata_replace()

According to Geert's report[0],

  kernel/padata.c: warning: 'err' may be used uninitialized in this
    function [-Wuninitialized]:  => 539:2

Warning is seen only with older compilers on certain archs.  The
runtime effect is potentially returning garbage down the stack when
padata's cpumasks are modified before any pcrypt requests have run.

Simplest fix is to initialize err to the success value.

[0] http://lkml.kernel.org/r/20200210135506.11536-1-geert@linux-m68k.org

Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Fixes: bbefa1dd6a6d ("crypto: pcrypt - Avoid deadlock by using per-instance padata queues")
Signed-off-by: Daniel Jordan <daniel.m.jordan@...cle.com>
Cc: Herbert Xu <herbert@...dor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@...unet.com>
Cc: linux-crypto@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
 kernel/padata.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 72777c10bb9c..62082597d4a2 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -512,7 +512,7 @@ static int padata_replace_one(struct padata_shell *ps)
 static int padata_replace(struct padata_instance *pinst)
 {
 	struct padata_shell *ps;
-	int err;
+	int err = 0;
 
 	pinst->flags |= PADATA_RESET;
 
-- 
2.24.1