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* [PATCH] selftests/exec: reject zero as power-of-two alignment
@ 2026-09-04 15:40 Paul Dolan
  0 siblings, 0 replies; only message in thread
From: Paul Dolan @ 2026-09-04 15:40 UTC (permalink / raw)
  To: Kees Cook, Shuah Khan; +Cc: linux-mm, linux-kselftest, linux-kernel

The load_address test reports whether an alignment was found separately
from whether that alignment is a power of two. However, the usual
x & (x - 1) check also evaluates to zero when x is zero, causing a
missing alignment to be reported as a power of two.

Require the alignment to be non-zero when reporting the power-of-two
result.

Fixes: b57a2907c9d9 ("selftests/exec: Build both static and non-static load_address tests")
Signed-off-by: Paul Dolan <paul.dolan.dev@gmail.com>
---
 tools/testing/selftests/exec/load_address.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/exec/load_address.c b/tools/testing/selftests/exec/load_address.c
index 55fd3732f029..e279d85e8f19 100644
--- a/tools/testing/selftests/exec/load_address.c
+++ b/tools/testing/selftests/exec/load_address.c
@@ -92,9 +92,10 @@ int main(int argc, char **argv)
 
 	/* Is the alignment sane? */
 	pow2 = extracted.alignment & (extracted.alignment - 1);
-	ksft_test_result(pow2 == 0,
-			 "Alignment is%s a power of 2: %#llx\n",
-			 pow2 == 0 ? "" : " NOT", extracted.alignment);
+	ksft_test_result(extracted.alignment != 0 && pow2 == 0,
+		"Alignment is%s a power of 2: %#llx\n",
+		extracted.alignment != 0 && pow2 == 0 ? "" : " NOT",
+		extracted.alignment);
 
 	/* Is the load address aligned? */
 	misalign = extracted.load_address & (extracted.alignment - 1);
-- 
2.55.0


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2026-09-04 15:40 [PATCH] selftests/exec: reject zero as power-of-two alignment Paul Dolan

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