[v1] vdso: Define NSEC_PER_SEC as 64-bit to prevent overflow

[PATCH] vdso: Define NSEC_PER_SEC as 64-bit to prevent overflow

Wake Liu posted 1 patch 2 months ago

Diff against v1
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include/vdso/time64.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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[PATCH] vdso: Define NSEC_PER_SEC as 64-bit to prevent overflow

Posted by Wake Liu 2 months ago

The constant NSEC_PER_SEC (1,000,000,000) is defined as a long literal.
On 32-bit systems like arm32, where long is 32 bits, this value can
overflow when used in 64-bit calculations.

This can lead to incorrect time calculations within the VDSO.

To fix this, define NSEC_PER_SEC as a long long literal (1000000000LL),
ensuring it is treated as a 64-bit value on all architectures and
preventing potential overflows.

Signed-off-by: Wake Liu <wakel@google.com>
---
 include/vdso/time64.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/vdso/time64.h b/include/vdso/time64.h
index b40cfa2aa33c..07641b27d139 100644
--- a/include/vdso/time64.h
+++ b/include/vdso/time64.h
@@ -8,7 +8,7 @@
 #define NSEC_PER_USEC	1000L
 #define NSEC_PER_MSEC	1000000L
 #define USEC_PER_SEC	1000000L
-#define NSEC_PER_SEC	1000000000L
+#define NSEC_PER_SEC	1000000000LL
 #define PSEC_PER_SEC	1000000000000LL
 #define FSEC_PER_SEC	1000000000000000LL
 
-- 
2.50.1.565.gc32cd1483b-goog