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authorJeff Layton <jlayton@redhat.com>2012-12-12 11:38:44 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-12-12 12:56:09 -0500
commit67fad106a219e083c91c79695bd1807dde1bf7b9 (patch)
tree77f79f5de4376beb4b9b6fde4b39b3786c717a9a /fs/nfs/direct.c
parentb0ef9647a0cd6cfd63fed48fbbe6005e4ba92571 (diff)
nfs: don't zero out the rest of the page if we hit the EOF on a DIO READ
Eryu provided a test program that would segfault when attempting to read past the EOF on file that was opened O_DIRECT. The buffer given to the read() call was on the stack, and when he attempted to read past it it would scribble over the rest of the stack page. If we hit the end of the file on a DIO READ request, then we don't want to zero out the rest of the buffer. These aren't pagecache pages after all, and there's no guarantee that the buffers that were passed in represent entire pages. Cc: <stable@vger.kernel.org> # v3.5+ Cc: Fred Isaman <iisaman@netapp.com> Reported-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/direct.c')
-rw-r--r--fs/nfs/direct.c8
1 files changed, 0 insertions, 8 deletions
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index cae26cbd59e..594f4e7e0b9 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -266,14 +266,6 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
struct nfs_page *req = nfs_list_entry(hdr->pages.next);
struct page *page = req->wb_page;
- if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
- if (bytes > hdr->good_bytes)
- zero_user(page, 0, PAGE_SIZE);
- else if (hdr->good_bytes - bytes < PAGE_SIZE)
- zero_user_segment(page,
- hdr->good_bytes & ~PAGE_MASK,
- PAGE_SIZE);
- }
if (!PageCompound(page)) {
if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
if (bytes < hdr->good_bytes)