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authorMiklos Szeredi <mszeredi@suse.cz>2010-06-08 16:28:45 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-06-10 19:08:34 +0200
commit1d862f41222b7f385bada9f85a67ca5592ffd33e (patch)
tree924baccaa8a5a56610db5c66020847b457679736 /fs/pipe.c
parent3e6c05052c262ebe7fdd85e75e9d4f956cdd8d82 (diff)
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>
Diffstat (limited to 'fs/pipe.c')
-rw-r--r--fs/pipe.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 69c4c7c13ea..f31e2d47298 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;