And thus when we try to use 'ss -danemi' on these sockets that have no ccid blocks (data collected using systemtap after I fixed the problem): dccp_diag_get_info sk=0xffff8801220a3100, dp->dccps_hc_rx_ccid=0x0000000000000000, dp->dccps_hc_tx_ccid=0x0000000000000000 We get an OOPS: mica.ghostprotocols.net login: BUG: unable to handle kernel NULL pointer dereferenc0 IP: [<ffffffffa0136082>] dccp_diag_get_info+0x82/0xc0 [dccp_diag] PGD 12106f067 PUD 122488067 PMD 0 Oops: 0000 [#1] PREEMPT Fix is trivial, and 'ss -d' is working again: [root@mica ~]# ss -danemi State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 0 *:5001 *:* ino:7288 sk:220a3100ffff8801 mem:(r0,w0,f0,t0) cwnd:0 ssthresh:0 [root@mica ~]# Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> diff --git a/net/dccp/diag.c b/net/dccp/diag.c index 652a1b6..b21f261 100644 --- a/net/dccp/diag.c +++ b/net/dccp/diag.c @@ -32,8 +32,11 @@ static void dccp_get_info(struct sock *sk, struct tcp_info *info) if (dp->dccps_hc_rx_ackvec != NULL) info->tcpi_options |= TCPI_OPT_SACK; - ccid_hc_rx_get_info(dp->dccps_hc_rx_ccid, sk, info); - ccid_hc_tx_get_info(dp->dccps_hc_tx_ccid, sk, info); + if (dp->dccps_hc_rx_ccid != NULL) + ccid_hc_rx_get_info(dp->dccps_hc_rx_ccid, sk, info); + + if (dp->dccps_hc_tx_ccid != NULL) + ccid_hc_tx_get_info(dp->dccps_hc_tx_ccid, sk, info); } static void dccp_diag_get_info(struct sock *sk, struct inet_diag_msg *r, -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
