From: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Subject: ramfs: fix nommu mmap with gaps in the page cache ramfs needs to check that pages are both physically contiguous and contiguous in the file. If the page cache happens to have, eg, page A for index 0 of the file, no page for index 1, and page A+1 for index 2, then an mmap of the first two pages of the file will succeed when it should fail. Link: https://lkml.kernel.org/r/20200914122239.GO6583@xxxxxxxxxxxxxxxxxxxx Fixes: 642fb4d1f1dd ("[PATCH] NOMMU: Provide shared-writable mmap support on ramfs") Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/ramfs/file-nommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ramfs/file-nommu.c~ramfs-fix-nommu-mmap-with-gaps-in-the-page-cache +++ a/fs/ramfs/file-nommu.c @@ -224,7 +224,7 @@ static unsigned long ramfs_nommu_get_unm if (!pages) goto out_free; - nr = find_get_pages(inode->i_mapping, &pgoff, lpages, pages); + nr = find_get_pages_contig(inode->i_mapping, pgoff, lpages, pages); if (nr != lpages) goto out_free_pages; /* leave if some pages were missing */ _
