From 93867c59b0bb29470873a427dc7f06ebaf305221 Mon Sep 17 00:00:00 2001
From: Pingfan Liu <piliu@redhat.com>
Date: Mon, 29 Mar 2021 17:33:06 +0800
Subject: [PATCH] libnuma: make numa_police_memory() free of race
When numa_police_memory() read-write to memory, it can risk the race of
another thread write to the same area.
Using atomic function to protect the read-write operation
Signed-off-by: Pingfan Liu <piliu@redhat.com>
---
libnuma.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/libnuma.c b/libnuma.c
index f073c50..7b8290c 100644
--- a/libnuma.c
+++ b/libnuma.c
@@ -864,8 +864,10 @@ void numa_police_memory(void *mem, size_t size)
{
int pagesize = numa_pagesize_int();
unsigned long i;
- for (i = 0; i < size; i += pagesize)
- ((volatile char*)mem)[i] = ((volatile char*)mem)[i];
+ char *p = mem;
+ for (i = 0; i < size; i += pagesize, p += pagesize)
+ __atomic_and_fetch(p, 0xff, __ATOMIC_RELAXED);
+
}
make_internal_alias(numa_police_memory);
--
2.29.2