[PATCH] usercopy: Add parentheses around assignment in test_copy_struct_from_user

* [PATCH] usercopy: Add parentheses around assignment in test_copy_struct_from_user
@ 2019-10-03 17:11 Nathan Chancellor
       [not found] ` <CAHrFyr4GFJHQLHOi_OuDVkhuKxfnf_VkTWk6MJ2Mn1EtWhpqjg@mail.gmail.com>
  2019-10-03 19:13 ` Christian Brauner
  0 siblings, 2 replies; 3+ messages in thread
From: Nathan Chancellor @ 2019-10-03 17:11 UTC (permalink / raw)
  To: Christian Brauner, Aleksa Sarai
  Cc: Kees Cook, linux-kernel, clang-built-linux, Nathan Chancellor

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@gmail.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


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