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FAILED: patch "[PATCH] more bio_map_user_iov() leak fixes" failed to apply to 4.4-stable tree

PATCH [email protected] 1 participant 1 message Oct 15, 2017

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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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 Mon Sep 17 00:00:00 2001

From: Al Viro <[email protected]>
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 [email protected]
Signed-off-by Al Viro <[email protected]>
block/bio.c +9 -5
index 0d6439e89acb..9e9606d26cc6 100644
@@ -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);