diff options
| author | Tomas Bortoli <tomasbortoli@gmail.com> | 2018-07-23 20:42:53 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-15 09:42:58 +0200 |
| commit | eb1ca07f4343b4e58b97e792a85d5ba1ba103f5d (patch) | |
| tree | 4cd09c7dab7f8b0267c235df6735cde216857288 /net/9p/trans_fd.c | |
| parent | a8e5ec201e3ab74a8afda07338e9fd8d0fccb5bb (diff) | |
net/9p/trans_fd.c: fix race by holding the lock
[ Upstream commit 9f476d7c540cb57556d3cc7e78704e6cd5100f5f ]
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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/9p/trans_fd.c')
| -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 2b543532e2f1..aa4586672cee 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -195,15 +195,14 @@ 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; } @@ -215,7 +214,6 @@ 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); @@ -224,6 +222,7 @@ 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 int @@ -379,8 +378,9 @@ 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; |