2020-12-11 13:32:25

by David Wysochanski

[permalink] [raw]
Subject: [PATCH] NFS4: Fix use-after-free in trace_event_raw_event_nfs4_set_lock

It is only safe to call the tracepoint before rpc_put_task() because
'data' is freed inside nfs4_lock_release (rpc_release).

Fixes: 48c9579a1afe ("Adding stateid information to tracepoints")
Signed-off-by: Dave Wysochanski <[email protected]>
---
fs/nfs/nfs4proc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d23edbc36803..6bf0457032c7 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7110,9 +7110,9 @@ static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *f
data->arg.new_lock_owner, ret);
} else
data->cancelled = true;
+ trace_nfs4_set_lock(fl, state, &data->res.stateid, cmd, ret);
rpc_put_task(task);
dprintk("%s: done, ret = %d!\n", __func__, ret);
- trace_nfs4_set_lock(fl, state, &data->res.stateid, cmd, ret);
return ret;
}

--
1.8.3.1