mm: silence data-race in update_hiwater_rss

KCSAN reports a data race on mm_cluster.hiwater_rss, which can be accessed
concurrently from various paths like page migration and memory unmapping
without synchronization.

Since hiwater_rss is a statistical field for accounting purposes, this
data race is benign.  Annotate both the read and write accesses with
data_race() to make KCSAN happy.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Lance Yang <[email protected]>
Reported-by: [email protected]
Closes: https://lore.kernel.org/linux-mm/[email protected]
Acked-by: Vlastimil Babka <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: ioworker0

include/linux/mm.h

@@ -2742,7 +2742,7 @@ static inline void update_hiwater_rss(struct mm_struct *mm)
 	unsigned long _rss = get_mm_rss(mm);
 
 	if (data_race(mm->hiwater_rss) < _rss)
-		(mm)->hiwater_rss = _rss;
+		data_race(mm->hiwater_rss = _rss);
 }
 
 static inline void update_hiwater_vm(struct mm_struct *mm)