Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755415Ab0FHO2y (ORCPT ); Tue, 8 Jun 2010 10:28:54 -0400 Received: from fxip-0047f.externet.hu ([88.209.222.127]:46322 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755297Ab0FHO2x (ORCPT ); Tue, 8 Jun 2010 10:28:53 -0400 To: jens.axboe@oracle.com CC: akpm@linux-foundation.org, torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] pipe: fix pipe buffer resizing Message-Id: From: Miklos Szeredi Date: Tue, 08 Jun 2010 16:28:45 +0200 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1627 Lines: 48 From: Miklos Szeredi pipe_set_size() needs to copy pipe bufs from the old circular buffer to the new. The current code gets this wrong in multiple ways, resulting in oops. Test program is available here: http://www.kernel.org/pub/linux/kernel/people/mszeredi/piperesize/ Signed-off-by: Miklos Szeredi --- fs/pipe.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) Index: linux.git/fs/pipe.c =================================================================== --- linux.git.orig/fs/pipe.c 2010-06-08 15:02:16.000000000 +0200 +++ linux.git/fs/pipe.c 2010-06-08 15:50:07.000000000 +0200 @@ -1145,13 +1145,20 @@ static long pipe_set_size(struct pipe_in * and adjust the indexes. */ if (pipe->nrbufs) { - const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1); - const unsigned int head = pipe->nrbufs - tail; + unsigned int tail; + unsigned int head; + tail = pipe->curbuf + pipe->nrbufs; + if (tail < pipe->buffers) + tail = 0; + else + tail &= (pipe->buffers - 1); + + head = pipe->nrbufs - tail; if (head) memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); if (tail) - memcpy(bufs + head, pipe->bufs + pipe->curbuf, tail * sizeof(struct pipe_buffer)); + memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer)); } pipe->curbuf = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/