3.7-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jeff Layton <[email protected]> commit 67fad106a219e083c91c79695bd1807dde1bf7b9 upstream. 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. Reported-by: Eryu Guan <[email protected]> Cc: Fred Isaman <[email protected]> Signed-off-by: Jeff Layton <[email protected]> Signed-off-by: Trond Myklebust <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/nfs/direct.c | 8 -------- 1 file changed, 8 deletions(-) --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -266,14 +266,6 @@ static void nfs_direct_read_completion(s 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) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
