diff options
| author | Guillaume Nault <g.nault@alphalink.fr> | 2018-04-12 20:50:35 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-04-13 12:17:26 -0400 |
| commit | f726214d9b23e5fce8c11937577a289a3202498f (patch) | |
| tree | 7143db7e1e7c2286a02f5f03a19bb0935e24456f /net/l2tp/l2tp_debugfs.c | |
| parent | 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 (diff) | |
l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file
Use l2tp_tunnel_get_nth() instead of l2tp_tunnel_find_nth(), to be safe
against concurrent tunnel deletion.
Use the same mechanism as in l2tp_ppp.c for dropping the reference
taken by l2tp_tunnel_get_nth(). That is, drop the reference just
before looking up the next tunnel. In case of error, drop the last
accessed tunnel in l2tp_dfs_seq_stop().
That was the last use of l2tp_tunnel_find_nth().
Fixes: 0ad6614048cf ("l2tp: Add debugfs files for dumping l2tp debug info")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp/l2tp_debugfs.c')
| -rw-r--r-- | net/l2tp/l2tp_debugfs.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c index 72e713da4733..b8f9d45bfeb1 100644 --- a/net/l2tp/l2tp_debugfs.c +++ b/net/l2tp/l2tp_debugfs.c @@ -47,7 +47,11 @@ struct l2tp_dfs_seq_data { static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd) { - pd->tunnel = l2tp_tunnel_find_nth(pd->net, pd->tunnel_idx); + /* Drop reference taken during previous invocation */ + if (pd->tunnel) + l2tp_tunnel_dec_refcount(pd->tunnel); + + pd->tunnel = l2tp_tunnel_get_nth(pd->net, pd->tunnel_idx); pd->tunnel_idx++; } @@ -96,7 +100,14 @@ static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos) static void l2tp_dfs_seq_stop(struct seq_file *p, void *v) { - /* nothing to do */ + struct l2tp_dfs_seq_data *pd = v; + + if (!pd || pd == SEQ_START_TOKEN) + return; + + /* Drop reference taken by last invocation of l2tp_dfs_next_tunnel() */ + if (pd->tunnel) + l2tp_tunnel_dec_refcount(pd->tunnel); } static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v) |