From: Pavel Begunkov <asml.silence@gmail.com> mainline inclusion from mainline-v5.12-rc1 commit 0f1d344feb534555a0dcd0beafb7211a37c5355e category: bugfix bugzilla: 188445,https://gitee.com/openeuler/kernel/issues/I6J5NZ Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- iter_file_splice_write() may spawn bvec segments with zero-length. In preparation for prohibiting them, filter out by hand at splice level. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Yang Erkun <yangerkun@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> --- fs/splice.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 6610e55c0e2a..96491e40d37c 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -662,12 +662,14 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, /* build the vector */ left = sd.total_len; - for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++, n++) { + for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) { struct pipe_buffer *buf = &pipe->bufs[tail & mask]; size_t this_len = buf->len; - if (this_len > left) - this_len = left; + /* zero-length bvecs are not supported, skip them */ + if (!this_len) + continue; + this_len = min(this_len, left); ret = pipe_buf_confirm(pipe, buf); if (unlikely(ret)) { @@ -680,6 +682,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, array[n].bv_len = this_len; array[n].bv_offset = buf->offset; left -= this_len; + n++; } iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left); -- 2.25.1