From: "Matthew Wilcox (Oracle)" willy@infradead.org
[ 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) willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Cc: David Howells dhowells@redhat.com Link: https://lkml.kernel.org/r/20200914122239.GO6583@casper.infradead.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ramfs/file-nommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c index 3ac1f2387083..5e1ebbe639eb 100644 --- a/fs/ramfs/file-nommu.c +++ b/fs/ramfs/file-nommu.c @@ -228,7 +228,7 @@ 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 */