[Crash-utility] PATCH: fix get_sock_info failure on 2.6.38

[Dave Anderson]

----- Original Message -----
> 2.6.38 introduced another change in struct inet_sock that breaks net -s
> like this:
> 
> crash-5.1.8> net -s 2494
> 
> net: invalid structure member offset: inet_opt_daddr
>      FILE: net.c  LINE: 829  FUNCTION: get_sock_info()
> 
> [/home/bobm/bin/crash-5.1.8] error trace: 4cccca => 4cb773 => 4ca4c0 => 4f766a
> PID: 2494   TASK: ffff8801226de540  CPU: 1   COMMAND: "racoon"
> FD      SOCKET            SOCK       FAMILY:TYPE SOURCE-PORT  DESTINATION-PORT
> 
>   4f766a: OFFSET_verify+202
>   4ca4c0: sym_socket_dump+1920
>   4cb773: dump_sockets_workhorse+1571
>   4cccca: cmd_net+3658
> 
>  3 ffff8801229470c0 ffff88011f8dfc00 net: invalid structure member offset: inet_opt_daddr
>      FILE: net.c  LINE: 829  FUNCTION: get_sock_info()
> 
> 
> This patch adds a new final clause to net_init to handle the case where
> inet_sock no longer contains inet_daddr (the previous final clause):
> 
> struct inet_sock {
>         /* sk and pinet6 has to be the first two members of inet_sock
>         */
>         struct sock             sk;
> #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
>         struct ipv6_pinfo       *pinet6;
> #endif
>         /* Socket demultiplex comparisons on incoming packets. */
> #define inet_daddr              sk.__sk_common.skc_daddr       <<<<<<<<<<<
> #define inet_rcv_saddr          sk.__sk_common.skc_rcv_saddr   <<<<<<<<<<<<
> 
> The patch cheats by depending on inet_sock having struct sock as its
> first element and struct sock having struct sock_common as its first
> element without actually verifying that.

Bob, 

Thanks for catching this.  And since it's easy enough to verify the offsets,
I've added a qualifier to the final clause:

--- net.c       25 Feb 2011 20:24:46 -0000      1.30
+++ net.c       17 Oct 2011 14:32:06 -0000
@@ -210,12 +210,19 @@
                                        MEMBER_OFFSET_INIT(inet_opt_dport, "inet_sock", "dport");
                                        MEMBER_OFFSET_INIT(inet_opt_sport, "inet_sock", "sport");
                                        MEMBER_OFFSET_INIT(inet_opt_num, "inet_sock", "num");
-                               } else {
+                               } else if (MEMBER_EXISTS("inet_sock", "inet_daddr")) {
                                        MEMBER_OFFSET_INIT(inet_opt_daddr, "inet_sock", "inet_daddr");
                                        MEMBER_OFFSET_INIT(inet_opt_rcv_saddr, "inet_sock", "inet_rcv_saddr");
                                        MEMBER_OFFSET_INIT(inet_opt_dport, "inet_sock", "inet_dport");
                                        MEMBER_OFFSET_INIT(inet_opt_sport, "inet_sock", "inet_sport");
                                        MEMBER_OFFSET_INIT(inet_opt_num, "inet_sock", "inet_num");
+                               } else if ((MEMBER_OFFSET("inet_sock", "sk") == 0) &&
+                                   (MEMBER_OFFSET("sock", "__sk_common") == 0)) {
+                                       MEMBER_OFFSET_INIT(inet_opt_daddr, "sock_common", "skc_daddr");
+                                       MEMBER_OFFSET_INIT(inet_opt_rcv_saddr, "sock_common", "skc_rcv_saddr");
+                                       MEMBER_OFFSET_INIT(inet_opt_dport, "inet_sock", "inet_dport");
+                                       MEMBER_OFFSET_INIT(inet_opt_sport, "inet_sock", "inet_sport");
+                                       MEMBER_OFFSET_INIT(inet_opt_num, "inet_sock", "inet_num");
                                }
                        }
 
Queued for crash-5.1.9.

Thanks,
  Dave