The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 Mon Sep 17 00:00:00 2001 From: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Date: Sat, 23 Sep 2017 15:51:23 -0400 Subject: [PATCH] more bio_map_user_iov() leak fixes we need to take care of failure exit as well - pages already in bio should be dropped by analogue of bio_unmap_pages(), since their refcounts had been bumped only once per reference in bio. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> diff --git a/block/bio.c b/block/bio.c index 0d6439e89acb..9e9606d26cc6 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1331,6 +1331,7 @@ struct bio *bio_map_user_iov(struct request_queue *q, int ret, offset; struct iov_iter i; struct iovec iov; + struct bio_vec *bvec; iov_for_each(iov, i, *iter) { unsigned long uaddr = (unsigned long) iov.iov_base; @@ -1375,7 +1376,12 @@ struct bio *bio_map_user_iov(struct request_queue *q, ret = get_user_pages_fast(uaddr, local_nr_pages, (iter->type & WRITE) != WRITE, &pages[cur_page]); - if (ret < local_nr_pages) { + if (unlikely(ret < local_nr_pages)) { + for (j = cur_page; j < page_limit; j++) { + if (!pages[j]) + break; + put_page(pages[j]); + } ret = -EFAULT; goto out_unmap; } @@ -1431,10 +1437,8 @@ struct bio *bio_map_user_iov(struct request_queue *q, return bio; out_unmap: - for (j = 0; j < nr_pages; j++) { - if (!pages[j]) - break; - put_page(pages[j]); + bio_for_each_segment_all(bvec, bio, j) { + put_page(bvec->bv_page); } out: kfree(pages);