diff options
| author | Kees Cook <keescook@chromium.org> | 2020-06-03 13:09:38 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2020-07-16 12:35:31 -0700 |
| commit | 63a0895d960aa3d3653ef0ecad5bd8579388f14b (patch) | |
| tree | 8c478682c2e05e4b1906235715fa4a92be2d2361 | |
| parent | 3f649ab728cda8038259d8f14492fe400fbab911 (diff) | |
compiler: Remove uninitialized_var() macro
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.
As recommended[2] by[3] Linus[4], remove the macro. With the recent
change to disable -Wmaybe-uninitialized in v5.7 in commit 78a5255ffb6a
("Stop the ad-hoc games with -Wno-maybe-initialized"), this is likely
the best time to make this treewide change.
[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Bart van Assche <bvanassche@acm.org>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | include/linux/compiler-clang.h | 2 | ||||
| -rw-r--r-- | include/linux/compiler-gcc.h | 6 | ||||
| -rw-r--r-- | tools/include/linux/compiler.h | 2 | ||||
| -rw-r--r-- | tools/virtio/linux/kernel.h | 2 |
4 files changed, 0 insertions, 12 deletions
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 5e55302e3bf6..8a072d00e688 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -5,8 +5,6 @@ /* Compiler specific definitions for Clang compiler */ -#define uninitialized_var(x) x = *(&(x)) - /* same as gcc, this was present in clang-2.6 so we can assume it works * with any version that can compile the kernel */ diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 1c74464c80c6..4099ac8b7f10 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -59,12 +59,6 @@ (typeof(ptr)) (__ptr + (off)); \ }) -/* - * A trick to suppress uninitialized variable warning without generating any - * code - */ -#define uninitialized_var(x) x = x - #ifdef CONFIG_RETPOLINE #define __noretpoline __attribute__((__indirect_branch__("keep"))) #endif diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h index 9f9002734e19..2f2f4082225e 100644 --- a/tools/include/linux/compiler.h +++ b/tools/include/linux/compiler.h @@ -111,8 +111,6 @@ # define noinline #endif -#define uninitialized_var(x) x = *(&(x)) - #include <linux/types.h> /* diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h index caab980211a6..315e85cabeda 100644 --- a/tools/virtio/linux/kernel.h +++ b/tools/virtio/linux/kernel.h @@ -110,8 +110,6 @@ static inline void free_page(unsigned long addr) const typeof( ((type *)0)->member ) *__mptr = (ptr); \ (type *)( (char *)__mptr - offsetof(type,member) );}) -#define uninitialized_var(x) x = x - # ifndef likely # define likely(x) (__builtin_expect(!!(x), 1)) # endif |