fuse: fix double request_end()

Refcounting of request is broken when fuse_abort_conn() is called and
request is on the fpq->io list:

 - ref is taken too late
 - then it is not dropped

Fixes: 0d8e84b0432b ("fuse: simplify request abort")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index c6b88fa85e2e..8564d91c7d41 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -371,7 +371,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
         struct fuse_iqueue *fiq = &fc->iq;
 
         if (test_and_set_bit(FR_FINISHED, &req->flags))
-                return;
+                goto out_put_req;
 
         spin_lock(&fiq->waitq.lock);
         list_del_init(&req->intr_entry);
@@ -400,6 +400,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
         wake_up(&req->waitq);
         if (req->end)
                 req->end(fc, req);
+out_put_req:
         fuse_put_request(fc, req);
 }
 
@@ -2105,6 +2106,7 @@ void fuse_abort_conn(struct fuse_conn *fc, bool is_abort)
                                 set_bit(FR_ABORTED, &req->flags);
                                 if (!test_bit(FR_LOCKED, &req->flags)) {
                                         set_bit(FR_PRIVATE, &req->flags);
+                                        __fuse_get_request(req);
                                         list_move(&req->list, &to_end1);
                                 }
                                 spin_unlock(&req->waitq.lock);
@@ -2131,7 +2133,6 @@ void fuse_abort_conn(struct fuse_conn *fc, bool is_abort)
 
                 while (!list_empty(&to_end1)) {
                         req = list_first_entry(&to_end1, struct fuse_req, list);
-                        __fuse_get_request(req);
                         list_del_init(&req->list);
                         request_end(fc, req);
                 }