Commit 7abcb84f authored by I Hsin Cheng's avatar I Hsin Cheng Committed by Andrew Morton
Browse files

lib/plist.c: enforce memory ordering in plist_check_list 

There exists an iteration over a plist in plist_check_list(), and memory
dependency exists between variables "prev", "next" and "prev->next".  As
plist is used in the scheduling subsystem, we should guarantee the memory
ordering between multiple processors.

Using macro "WRITE_ONCE()" can help us to ensure the memory ordering as
it was stated in "Documentation/memory-barriers.txt".

Link: https://lkml.kernel.org/r/20240526140139.17220-1-richard120310@gmail.com


Signed-off-by: default avatarI Hsin Cheng <richard120310@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 87beb669

lib/plist.c

+2 −2
Original line number Diff line number Diff line
@@ -47,8 +47,8 @@ static void plist_check_list(struct list_head *top) 


	plist_check_prev_next(top, prev, next);

	while (next != top) {

		prev = next;

		next = prev->next;

		WRITE_ONCE(prev, next);

		WRITE_ONCE(next, prev->next);

		plist_check_prev_next(top, prev, next);

	}

}