The commit is pushed to "branch-rh7-3.10.0-229.7.2.vz7.8.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.8.5
------>
commit 654ec46a26256b119505ba7dcc48e60c3c6a5cf5
Author: Maxim Patlasov <mpatla...@virtuozzo.com>
Date: Mon Oct 12 14:19:03 2015 +0400
ms/fuse: break infinite loop in fuse_fill_write_pages()
Backport bugfix from LKML. Original patch description:
I got a report about unkillable task eating CPU. Thge further
investigation shows, that the problem is in the fuse_fill_write_pages()
function. If iov's first segment has zero length, we get an infinite
loop, because we never reach iov_iter_advance() call.
Fix this by calling iov_iter_advance() before repeating an attempt to
copy data from userspace.
A similar problem is described in 124d3b7041f ("fix writev regression:
pan hanging unkillable and un-straceable").
Signed-off-by: Roman Gushchin <kl...@yandex-team.ru>
Cc: Miklos Szeredi <mik...@szeredi.hu>
Signed-off-by: Maxim Patlasov <mpatla...@virtuozzo.com>
Acked-by: Dmitry Monakhov <dmonak...@virtuozzo.com>
---
fs/fuse/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index a5c4125..88e6e46 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1327,6 +1327,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
mark_page_accessed(page);
+ iov_iter_advance(ii, tmp);
if (!tmp) {
unlock_page(page);
page_cache_release(page);
@@ -1339,7 +1340,6 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
req->page_descs[req->num_pages].length = tmp;
req->num_pages++;
- iov_iter_advance(ii, tmp);
count += tmp;
pos += tmp;
offset += tmp;
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