3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> commit abc1be13fd113ddef5e2d807a466286b864caed3 upstream. f2fs specifies the __GFP_ZERO flag for allocating some of its pages. Unfortunately, the page cache also uses the mapping's GFP flags for allocating radix tree nodes. It always masked off the __GFP_HIGHMEM flag, and masks off __GFP_ZERO in some paths, but not all. That causes radix tree nodes to be allocated with a NULL list_head, which causes backtraces like: __list_del_entry+0x30/0xd0 list_lru_del+0xac/0x1ac page_cache_tree_insert+0xd8/0x110 The __GFP_DMA and __GFP_DMA32 flags would also be able to sneak through if they are ever used. Fix them all by using GFP_RECLAIM_MASK at the innermost location, and remove it from earlier in the callchain. Link: http://lkml.kernel.org/r/20180411060320.14458-2-willy@xxxxxxxxxxxxx Fixes: 449dd6984d0e ("mm: keep page cache radix tree nodes in check") Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> Reported-by: Chris Fries <cfries@xxxxxxxxxx> Debugged-by: Minchan Kim <minchan@xxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> [bwh: Backported to 3.16: - Drop change in page_cache_read(), which always passes GFP_KERNEL - Adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- --- a/mm/filemap.c +++ b/mm/filemap.c @@ -529,7 +529,7 @@ int replace_page_cache_page(struct page VM_BUG_ON_PAGE(!PageLocked(new), new); VM_BUG_ON_PAGE(new->mapping, new); - error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); + error = radix_tree_preload(gfp_mask & GFP_RECLAIM_MASK); if (!error) { struct address_space *mapping = old->mapping; void (*freepage)(struct page *); @@ -576,7 +576,7 @@ static int __add_to_page_cache_locked(st if (error) return error; - error = radix_tree_maybe_preload(gfp_mask & ~__GFP_HIGHMEM); + error = radix_tree_maybe_preload(gfp_mask & GFP_RECLAIM_MASK); if (error) { mem_cgroup_uncharge_cache_page(page); return error; @@ -1111,8 +1111,7 @@ no_page: if (fgp_flags & FGP_ACCESSED) init_page_accessed(page); - err = add_to_page_cache_lru(page, mapping, offset, - gfp_mask & GFP_RECLAIM_MASK); + err = add_to_page_cache_lru(page, mapping, offset, gfp_mask); if (unlikely(err)) { page_cache_release(page); page = NULL;
