diff options
| author | Minchan Kim <minchan@kernel.org> | 2017-02-25 01:59:59 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-06-05 23:17:16 +0300 |
| commit | 1c38d1cd062ab7b76e37e35df7b23e0ca593dddc (patch) | |
| tree | e330fe70f4253f5a2d3f4530e2d3dc07a467e2fb /mm/filemap.c | |
| parent | 8c338cd1301c72ff7667f00a131c98da3ca2c995 (diff) | |
| download | linux-1c38d1cd062ab7b76e37e35df7b23e0ca593dddc.tar.xz | |
mm: do not access page->mapping directly on page_endio
commit dd8416c47715cf324c9a16f13273f9fda87acfed upstream.
With rw_page, page_endio is used for completing IO on a page and it
propagates write error to the address space if the IO fails. The
problem is it accesses page->mapping directly which might be okay for
file-backed pages but it shouldn't for anonymous page. Otherwise, it
can corrupt one of field from anon_vma under us and system goes panic
randomly.
swap_writepage
bdev_writepage
ops->rw_page
I encountered the BUG during developing new zram feature and it was
really hard to figure it out because it made random crash, somtime
mmap_sem lockdep, sometime other places where places never related to
zram/zsmalloc, and not reproducible with some configuration.
When I consider how that bug is subtle and people do fast-swap test with
brd, it's worth to add stable mark, I think.
Fixes: dd6bd0d9c7db ("swap: use bdev_read_page() / bdev_write_page()")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 31b5b25c3d2d..128f3d34d874 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -795,9 +795,12 @@ void page_endio(struct page *page, int rw, int err) unlock_page(page); } else { /* rw == WRITE */ if (err) { + struct address_space *mapping; + SetPageError(page); - if (page->mapping) - mapping_set_error(page->mapping, err); + mapping = page_mapping(page); + if (mapping) + mapping_set_error(mapping, err); } end_page_writeback(page); } |