fuse: fix pipe_buf_operations
Having this struct in module memory could Oops when if the module is
unloaded while the buffer still persists in a pipe.
Since sock_pipe_buf_ops is essentially the same as fuse_dev_pipe_buf_steal
merge them into nosteal_pipe_buf_ops (this is the same as
default_pipe_buf_ops except stealing the page from the buffer is not
allowed).
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ef74ad5..fa8cb4b 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1296,22 +1296,6 @@
return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
}
-static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
- struct pipe_buffer *buf)
-{
- return 1;
-}
-
-static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
- .can_merge = 0,
- .map = generic_pipe_buf_map,
- .unmap = generic_pipe_buf_unmap,
- .confirm = generic_pipe_buf_confirm,
- .release = generic_pipe_buf_release,
- .steal = fuse_dev_pipe_buf_steal,
- .get = generic_pipe_buf_get,
-};
-
static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len, unsigned int flags)
@@ -1358,7 +1342,11 @@
buf->page = bufs[page_nr].page;
buf->offset = bufs[page_nr].offset;
buf->len = bufs[page_nr].len;
- buf->ops = &fuse_dev_pipe_buf_ops;
+ /*
+ * Need to be careful about this. Having buf->ops in module
+ * code can Oops if the buffer persists after module unload.
+ */
+ buf->ops = &nosteal_pipe_buf_ops;
pipe->nrbufs++;
page_nr++;