From: Matthew Wilcox (Oracle) Date: Fri, 16 Oct 2020 03:13:04 +0000 (-0700) Subject: ramfs: fix nommu mmap with gaps in the page cache X-Git-Tag: v5.8.17~212 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0a80f93ccd61ea7c9533d8f68f0a83ee5fd09639;p=thirdparty%2Fkernel%2Fstable.git ramfs: fix nommu mmap with gaps in the page cache [ Upstream commit 50b7d85680086126d7bd91dae81d57d4cb1ab6b7 ] 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. Fixes: 642fb4d1f1dd ("[PATCH] NOMMU: Provide shared-writable mmap support on ramfs") Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Cc: David Howells Link: https://lkml.kernel.org/r/20200914122239.GO6583@casper.infradead.org Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c index 4146954549560..355523f4a4bf3 100644 --- a/fs/ramfs/file-nommu.c +++ b/fs/ramfs/file-nommu.c @@ -224,7 +224,7 @@ static unsigned long ramfs_nommu_get_unmapped_area(struct file *file, 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 */