diff mbox series

[143/156] ramfs: fix nommu mmap with gaps in the page cache

Message ID 20201016025000.TP1DS3-C6%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/156] device-dax/kmem: fix resource release | expand

Commit Message

Andrew Morton Oct. 16, 2020, 2:50 a.m. UTC 
From: Matthew Wilcox (Oracle) <willy@infradead.org>
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@casper.infradead.org
Fixes: 642fb4d1f1dd ("[PATCH] NOMMU: Provide shared-writable mmap support on ramfs")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ramfs/file-nommu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- 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 */