diff options
| author | Tomas Bortoli <tomasbortoli@gmail.com> | 2018-07-23 20:42:53 +0200 |
|---|---|---|
| committer | Dominique Martinet <dominique.martinet@cea.fr> | 2018-08-13 09:34:58 +0900 |
| commit | 9f476d7c540cb57556d3cc7e78704e6cd5100f5f (patch) | |
| tree | d4892ba2088c3022a47fc7db4fe7b2ecea5ebe4a | |
| parent | 430ac66eb4c5b5c4eb846b78ebf65747510b30f1 (diff) | |
net/9p/trans_fd.c: fix race by holding the lock
It may be possible to run p9_fd_cancel() with a deleted req->req_list
and incur in a double del. To fix hold the client->lock while changing
the status, so the other threads will be synchronized.
Link: http://lkml.kernel.org/r/20180723184253.6682-1-tomasbortoli@gmail.com
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+735d926e9d1317c3310c@syzkaller.appspotmail.com
To: Eric Van Hensbergen <ericvh@gmail.com>
To: Ron Minnich <rminnich@sandia.gov>
To: Latchesar Ionkov <lucho@ionkov.net>
Cc: Yiwen Jiang <jiangyiwen@huwei.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
| -rw-r--r-- | net/9p/trans_fd.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index b161184f77f6..cce41b20a709 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -199,15 +199,14 @@ static void p9_mux_poll_stop(struct p9_conn *m) static void p9_conn_cancel(struct p9_conn *m, int err) { struct p9_req_t *req, *rtmp; - unsigned long flags; LIST_HEAD(cancel_list); p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err); - spin_lock_irqsave(&m->client->lock, flags); + spin_lock(&m->client->lock); if (m->err) { - spin_unlock_irqrestore(&m->client->lock, flags); + spin_unlock(&m->client->lock); return; } @@ -219,7 +218,6 @@ static void p9_conn_cancel(struct p9_conn *m, int err) list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) { list_move(&req->req_list, &cancel_list); } - spin_unlock_irqrestore(&m->client->lock, flags); list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req); @@ -228,6 +226,7 @@ static void p9_conn_cancel(struct p9_conn *m, int err) req->t_err = err; p9_client_cb(m->client, req, REQ_STATUS_ERROR); } + spin_unlock(&m->client->lock); } static __poll_t @@ -375,8 +374,9 @@ static void p9_read_work(struct work_struct *work) if (m->req->status != REQ_STATUS_ERROR) status = REQ_STATUS_RCVD; list_del(&m->req->req_list); - spin_unlock(&m->client->lock); + /* update req->status while holding client->lock */ p9_client_cb(m->client, m->req, status); + spin_unlock(&m->client->lock); m->rc.sdata = NULL; m->rc.offset = 0; m->rc.capacity = 0; |