The patch titled
Subject: percpu: add a test case for the specific 64-bit value addition
has been added to the -mm mm-unstable branch. Its filename is
percpu-add-a-test-case-for-the-specific-64-bit-value-addition.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/percpu-add-a-test-case-for-the-specific-64-bit-value-addition.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Subject: percpu: add a test case for the specific 64-bit value addition
Date: Wed, 16 Oct 2024 21:23:52 +0300
It might be a corner case when we add UINT_MAX as 64-bit unsigned value to
the percpu variable as it's not the same as -1 (ULONG_LONG_MAX). Add a
test case for that.
Link: https://lkml.kernel.org/r/20241016182635.1156168-3-andriy.shevchenko@xxxxxxxxxxxxxxx
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Uros Bizjak <ubizjak@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/percpu_test.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
--- a/lib/percpu_test.c~percpu-add-a-test-case-for-the-specific-64-bit-value-addition
+++ a/lib/percpu_test.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/limits.h>
#include <linux/module.h>
/* validate @native and @pcp counter values match @expected */
@@ -24,8 +25,9 @@ static int __init percpu_test_init(void)
* +ul_one/-ul_one below would replace with inc/dec instructions.
*/
volatile unsigned int ui_one = 1;
- long l = 0;
+ unsigned long long ull = 0;
unsigned long ul = 0;
+ long l = 0;
pr_info("percpu test start\n");
@@ -112,6 +114,13 @@ static int __init percpu_test_init(void)
CHECK(ul, ulong_counter, -1);
CHECK(ul, ulong_counter, ULONG_MAX);
+ ul = ull = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul = ull += UINT_MAX;
+ __this_cpu_add(ulong_counter, ull);
+ CHECK(ul, ulong_counter, UINT_MAX);
+
ul = 3;
__this_cpu_write(ulong_counter, 3);
_
Patches currently in -mm which might be from andriy.shevchenko@xxxxxxxxxxxxxxx are
mm-remove-unused-stub-for-can_swapin_thp.patch
x86-percpu-fix-clang-warning-when-dealing-with-unsigned-types.patch
percpu-add-a-test-case-for-the-specific-64-bit-value-addition.patch
resource-replace-open-coded-resource_intersection.patch
resource-introduce-is_type_match-helper-and-use-it.patch
