Re: Hitting BUG_ON trap in read_pages() - : [PATCH v2] mm: Optimise put_pages_list()
From: Namjae Jeon <linkinjeon@kernel.org>
Date: 2021-11-09 23:12:47
Also in:
linux-fsdevel
2021-11-09 22:34 GMT+09:00, Matthew Wilcox [off-list ref]:
On Tue, Nov 09, 2021 at 07:45:47PM +0900, Namjae Jeon wrote:quoted
Hi Matthew, This patch is hitting BUG_ON trap in read_pages() when running xfstests for cifs. There seems to be a same issue with other filesystems using .readpages ?The real fix, of course, is to migrate away from using ->readpages ;-) I think both 9p and nfs are going away this cycle. CIFS really needs to move to using the netfs interfaces.
Okay.
quoted
Could you please take a look ?Please try this patch:
Work fine.
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.
Fixes: 988c69f1bc23 ("mm: optimise put_pages_list()")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>Tested-by: Namjae Jeon <linkinjeon@kernel.org> Thanks!
quoted hunk ↗ jump to hunk
diff --git a/mm/swap.c b/mm/swap.c index 1841c24682f8..e8c9dc6d0377 100644 --- a/mm/swap.c +++ b/mm/swap.c@@ -156,6 +156,7 @@ void put_pages_list(struct list_head *pages) } free_unref_page_list(pages); + INIT_LIST_HEAD(pages); } EXPORT_SYMBOL(put_pages_list);