From 1d862f41222b7f385bada9f85a67ca5592ffd33e Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@suse.cz>
Date: Tue, 8 Jun 2010 16:28:45 +0200
Subject: [PATCH] pipe: fix pipe buffer resizing
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 <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---
fs/pipe.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index 69c4c7c13ea9..f31e2d472984 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1145,13 +1145,20 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
* 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;
--
GitLab