Re: [PATCH] block: Fix potential page reference leak in __bio_iov_append_get_pages()

[linmiaohe]

Johannes Thumshirn  wrote:
>On 05/09/2020 11:41, Miaohe Lin wrote:
>> When bio_add_hw_page() failed, we left page reference still held in pages.
>
>I'd add "from iov_iter_get_pages()" to the above sentence.
>

Sounds good. Will add it in v2.

>Otherwise
>Reviewed-by: Johannes Thumshirn 

Many Thanks for review.

Re: [PATCH] block: Fix potential page reference leak in __bio_iov_append_get_pages()

[Johannes Thumshirn]

On 05/09/2020 11:41, Miaohe Lin wrote:
> When bio_add_hw_page() failed, we left page reference still held in pages.

I'd add "from iov_iter_get_pages()" to the above sentence.

Otherwise
Reviewed-by: Johannes Thumshirn 

[PATCH] block: Fix potential page reference leak in __bio_iov_append_get_pages()

[Miaohe Lin]

When bio_add_hw_page() failed, we left page reference still held in pages.
Release these references and advance the iov_iter according to what we
have done successfully yet.

Fixes: 0512a75b98f8 ("block: Introduce REQ_OP_ZONE_APPEND")
Signed-off-by: Miaohe Lin 
---
 block/bio.c | 12 +++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index e113073958cb..a323a5446221 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1080,7 +1080,7 @@ static int __bio_iov_append_get_pages(struct bio *bio, 
struct iov_iter *iter)
len = min_t(size_t, PAGE_SIZE - offset, left);
if (bio_add_hw_page(q, bio, page, len, offset,
max_append_sectors, _page) != len)
-   return -EINVAL;
+   goto put_pages;
if (same_page)
put_page(page);
offset = 0;
@@ -1088,6 +1088,16 @@ static int __bio_iov_append_get_pages(struct bio *bio, 
struct iov_iter *iter)
 
iov_iter_advance(iter, size);
return 0;
+put_pages:
+   iov_iter_advance(iter, size - left);
+   for (; left > 0; left -= len, i++) {
+   struct page *page = pages[i];
+
+   len = min_t(size_t, PAGE_SIZE - offset, left);
+   put_page(page);
+   offset = 0;
+   }
+   return -EINVAL;
 }
 
 /**
-- 
2.19.1