[01/15] mm/swap.c:put_pages_list(): reinitialise the page list

Commit Message

Andrew Morton Nov. 20, 2021, 12:43 a.m. UTC

From: Matthew Wilcox <[e-mail]>
Subject: mm/swap.c:put_pages_list(): reinitialise the page list

While free_unref_page_list() puts pages onto the CPU local LRU list, it
does not remove them from the list they were passed in on.  That makes the
list_head appear to be non-empty, and would lead to various corruption
problems if we didn't have an assertion that the list was empty.

Reinitialise the list after calling free_unref_page_list() to avoid this
problem.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 988c69f1bc23 ("mm: optimise put_pages_list()")
Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>
Reviewed-by: Steve French <[e-mail]>
Reported-by: Namjae Jeon <[e-mail]>
Tested-by: Steve French <[e-mail]>
Tested-by: Namjae Jeon <[e-mail]>
Cc: Steve French <[e-mail]>
Cc: Hyeoncheol Lee <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/swap.c |    1 +
 1 file changed, 1 insertion(+)

Patch

--- a/mm/swap.c~hitting-bug_on-trap-in-read_pages-mm-optimise-put_pages_list
+++ a/mm/swap.c
@@ -156,6 +156,7 @@  void put_pages_list(struct list_head *pa
 	}
 
 	free_unref_page_list(pages);
+	INIT_LIST_HEAD(pages);
 }
 EXPORT_SYMBOL(put_pages_list);