This is a note to let you know that I've just added the patch titled mm: do not access page->mapping directly on page_endio to the 4.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-do-not-access-page-mapping-directly-on-page_endio.patch and it can be found in the queue-4.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From dd8416c47715cf324c9a16f13273f9fda87acfed Mon Sep 17 00:00:00 2001 From: Minchan Kim <minchan@xxxxxxxxxx> Date: Fri, 24 Feb 2017 14:59:59 -0800 Subject: mm: do not access page->mapping directly on page_endio From: Minchan Kim <minchan@xxxxxxxxxx> 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@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/filemap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1002,9 +1002,12 @@ void page_endio(struct page *page, bool unlock_page(page); } else { 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); } Patches currently in stable-queue which might be from minchan@xxxxxxxxxx are queue-4.10/mm-vmpressure-fix-sending-wrong-events-on-underflow.patch queue-4.10/mm-vmscan-consider-eligible-zones-in-get_scan_count.patch queue-4.10/mm-vmscan-cleanup-lru-size-claculations.patch queue-4.10/mm-do-not-access-page-mapping-directly-on-page_endio.patch queue-4.10/mm-balloon-umount-balloon_mnt-when-removing-vb-device.patch