linux-kernel - [PATCH] usercopy: Add parentheses around assignment in test_copy_struct_from

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Message-Id: <20191003171121.2723619-1-natechancellor@gmail.com>
Date:   Thu,  3 Oct 2019 10:11:21 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Christian Brauner <christian.brauner@...ntu.com>,
        Aleksa Sarai <cyphar@...har.com>
Cc:     Kees Cook <keescook@...omium.org>, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH] usercopy: Add parentheses around assignment in test_copy_struct_from_user

Clang warns:

lib/test_user_copy.c:96:10: warning: using the result of an assignment
as a condition without parentheses [-Wparentheses]
        if (ret |= test(umem_src == NULL, "kmalloc failed"))
            ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/test_user_copy.c:96:10: note: place parentheses around the
assignment to silence this warning
        if (ret |= test(umem_src == NULL, "kmalloc failed"))
                ^
            (                                              )
lib/test_user_copy.c:96:10: note: use '!=' to turn this compound
assignment into an inequality comparison
        if (ret |= test(umem_src == NULL, "kmalloc failed"))
                ^~
                !=

Add the parentheses as it suggests because this is intentional.

Fixes: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper")
Link: https://github.com/ClangBuiltLinux/linux/issues/731
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 lib/test_user_copy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
index 950ee88cd6ac..e365ace06538 100644
--- a/lib/test_user_copy.c
+++ b/lib/test_user_copy.c
@@ -93,11 +93,11 @@ static int test_copy_struct_from_user(char *kmem, char __user *umem,
 	size_t ksize, usize;
 
 	umem_src = kmalloc(size, GFP_KERNEL);
-	if (ret |= test(umem_src == NULL, "kmalloc failed"))
+	if ((ret |= test(umem_src == NULL, "kmalloc failed")))
 		goto out_free;
 
 	expected = kmalloc(size, GFP_KERNEL);
-	if (ret |= test(expected == NULL, "kmalloc failed"))
+	if ((ret |= test(expected == NULL, "kmalloc failed")))
 		goto out_free;
 
 	/* Fill umem with a fixed byte pattern. */
-- 
2.23.0