linux-kernel - [RFC PATCH v1 48/50] arch/arm/kernel/process.c: Use get_random_max32() for sigpage

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Message-Id: <202003281643.02SGhPfO016133@sdf.org>
Date:   Fri, 29 Nov 2019 18:57:36 -0500
From:   George Spelvin <lkml@....org>
To:     linux-kernel@...r.kernel.org, lkml@....org
Cc:     Nathan Lynch <nathan_lynch@...tor.com>,
        Dmitry Safonov <0x7f454c46@...il.com>,
        Russell King <linux@...linux.org.uk>,
        linux-arm-kernel@...ts.infradead.org
Subject: [RFC PATCH v1 48/50] arch/arm/kernel/process.c: Use
 get_random_max32() for sigpage_addr()

Which is faster and less biased than get_random_int() % range

Signed-off-by: George Spelvin <lkml@....org>
Cc: Nathan Lynch <nathan_lynch@...tor.com>
Cc: Dmitry Safonov <0x7f454c46@...il.com>
Cc: Russell King <linux@...linux.org.uk>
Cc: linux-arm-kernel@...ts.infradead.org
---
 arch/arm/kernel/process.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 46e478fb5ea20..9f2556be33505 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -391,7 +391,7 @@ static unsigned long sigpage_addr(const struct mm_struct *mm,
 
 	slots = ((last - first) >> PAGE_SHIFT) + 1;
 
-	offset = get_random_int() % slots;
+	offset = get_random_max32(slots);
 
 	addr = first + (offset << PAGE_SHIFT);
 
-- 
2.26.0