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| author | Kees Cook <kees@kernel.org> | 2024-11-17 03:38:13 -0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-12-05 19:54:47 -0800 |
| commit | 5c3793604f91123bf49bc792ce697a0bef4c173c (patch) | |
| tree | a9080699dd5d0f87b75fde28d2604d5b9d46adb6 | |
| parent | 3203b3ab0fcf22132caadd72caebfad47bf0dd2b (diff) | |
| download | lwn-5c3793604f91123bf49bc792ce697a0bef4c173c.tar.gz lwn-5c3793604f91123bf49bc792ce697a0bef4c173c.zip | |
lib: stackinit: hide never-taken branch from compiler
The never-taken branch leads to an invalid bounds condition, which is by
design. To avoid the unwanted warning from the compiler, hide the
variable from the optimizer.
../lib/stackinit_kunit.c: In function 'do_nothing_u16_zero':
../lib/stackinit_kunit.c:51:49: error: array subscript 1 is outside array bounds of 'u16[0]' {aka 'short unsigned int[]'} [-Werror=array-bounds=]
51 | #define DO_NOTHING_RETURN_SCALAR(ptr) *(ptr)
| ^~~~~~
../lib/stackinit_kunit.c:219:24: note: in expansion of macro 'DO_NOTHING_RETURN_SCALAR'
219 | return DO_NOTHING_RETURN_ ## which(ptr + 1); \
| ^~~~~~~~~~~~~~~~~~
Link: https://lkml.kernel.org/r/20241117113813.work.735-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | lib/stackinit_kunit.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/stackinit_kunit.c b/lib/stackinit_kunit.c index c14c6f8e6308..c40818ec9c18 100644 --- a/lib/stackinit_kunit.c +++ b/lib/stackinit_kunit.c @@ -212,6 +212,7 @@ static noinline void test_ ## name (struct kunit *test) \ static noinline DO_NOTHING_TYPE_ ## which(var_type) \ do_nothing_ ## name(var_type *ptr) \ { \ + OPTIMIZER_HIDE_VAR(ptr); \ /* Will always be true, but compiler doesn't know. */ \ if ((unsigned long)ptr > 0x2) \ return DO_NOTHING_RETURN_ ## which(ptr); \ |