While experimenting with some dccp fuzzing, I hit this..
Oops: 0010 [#1] PREEMPT SMP DEBUG_PAGEALLOC
CPU: 3 PID: 19269 Comm: trinity-c22 Not tainted 4.2.0-rc2-think+ #2
task: ffff88006f3954c0 ti: ffff8802b89b0000 task.ti: ffff8802b89b0000
RIP: 0010:[<0000000000000000>] [< (null)>] (null)
RSP: 0018:ffff8802b89b3e30 EFLAGS: 00010246
RAX: ffffffffc063b200 RBX: 000000000000908c RCX: 000000000000908c
RDX: 0000000000000001 RSI: ffff8800cb94ef00 RDI: ffff880501ad8c40
RBP: ffff8802b89b3eb8 R08: ffff8800cb94ef00 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000005 R12: 000000000000908c
R13: ffffffffc0631940 R14: ffffffffafeefd40 R15: ffff8800cc97e850
FS: 00007fc948b0b740(0000) GS:ffff880507e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000024f2d2000 CR4: 00000000001407e0
DR0: 00007fe46baf0000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Stack:
ffffffffaf725ae5 ffff8802b89b3e48 000003e800000005 ffff8802b89b3e68
ffff880501ad8c40 ffff8800cb94ef00 ffff880033cc8000 ffffffffb89b3e88
ffffffff00000000 ffff880501ad9200 ffff880501ad9200 ffff8802b89b3eb8
Call Trace:
[<ffffffffaf725ae5>] ? inet_csk_get_port+0x3a5/0x4f0
[<ffffffffaf7260a9>] inet_csk_listen_start+0x79/0xe0
[<ffffffffc06260bb>] inet_dccp_listen+0x8b/0xc0 [dccp]
[<ffffffffaf6b509e>] SyS_listen+0x4e/0x80
[<ffffffffaf80063c>] tracesys_phase2+0x84/0x89
inet_csk_listen_start has an insightful comment about a potential race.
I added this for debugging..
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 60021d0d9326..d53cba9c1dfd 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -814,11 +814,15 @@ int inet_csk_listen_start(struct sock *sk, const int
nr_table_entries)
inet->inet_sport = htons(inet->inet_num);
sk_dst_reset(sk);
+ if (sk->sk_prot->hash == NULL) {
+ printk("sk->sk_prot->hash WAS NULL!\n");
+ goto out;
+ }
sk->sk_prot->hash(sk);
return 0;
}
-
+out:
sk->sk_state = TCP_CLOSE;
__reqsk_queue_destroy(&icsk->icsk_accept_queue);
return -EADDRINUSE;
But haven't been able to provoke it into happening again.
Is a null check sufficient here, or should this be solved
elsewhere ?
Dave
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