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Message-ID: <20250805162031.952223-1-wakel@google.com>
Date: Wed, 6 Aug 2025 00:20:30 +0800
From: Wake Liu <wakel@...gle.com>
To: Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
Vincenzo Frascino <vincenzo.frascino@....com>
Cc: linux-kernel@...r.kernel.org, wakel@...gle.com
Subject: [PATCH] vdso: Define NSEC_PER_SEC as 64-bit to prevent overflow
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@...gle.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
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