Messages in this thread Patch in this message | | | From | linke li <> | Subject | [PATCH] mm/swapfile: mark racy access on si->highest_bit | Date | Sat, 27 Apr 2024 14:29:56 +0800 |
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In scan_swap_map_slots(), si->highest_bit can by changed by swap_range_alloc() concurrently. All reads on si->highest_bit except one is either protected by lock or read using READ_ONCE. So mark the one racy read on si->highest_bit as benign using READ_ONCE.
This patch is aimed at reducing the number of benign races reported by KCSAN in order to focus future debugging effort on harmful races.
Signed-off-by: linke li <lilinke99@qq.com> --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c index 556ff7347d5f..fb2243f7f06b 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -854,7 +854,7 @@ static int scan_swap_map_slots(struct swap_info_struct *si, last_in_cluster = offset + SWAPFILE_CLUSTER - 1; /* Locate the first empty (unaligned) cluster */ - for (; last_in_cluster <= si->highest_bit; offset++) { + for (; last_in_cluster <= READ_ONCE(si->highest_bit); offset++) { if (si->swap_map[offset]) last_in_cluster = offset + SWAPFILE_CLUSTER; else if (offset == last_in_cluster) { -- 2.39.3 (Apple Git-146)
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