diff options
| author | Miklos Szeredi <mszeredi@suse.cz> | 2010-06-08 16:28:45 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2010-06-10 19:08:34 +0200 |
| commit | 1d862f41222b7f385bada9f85a67ca5592ffd33e (patch) | |
| tree | 924baccaa8a5a56610db5c66020847b457679736 /fs/pipe.c | |
| parent | 3e6c05052c262ebe7fdd85e75e9d4f956cdd8d82 (diff) | |
| download | lwn-1d862f41222b7f385bada9f85a67ca5592ffd33e.tar.gz lwn-1d862f41222b7f385bada9f85a67ca5592ffd33e.zip | |
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.c | 13 |
1 files 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; |