Kernel sockets do not hold a reference for the network namespace to
which they point. Socket destruction broadcasting relies on the
network namespace and will cause the splat below when a kernel socket
is destroyed.
This fix simply ignores kernel sockets when they are destroyed.
Reported as:
general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
CPU: 1 PID: 9130 Comm: kworker/1:1 Not tainted 4.1.0-gelk-debug+ #1
Workqueue: sock_diag_events sock_diag_broadcast_destroy_work
Stack:
ffff8800b9c586c0 ffff8800b9c586c0 ffff8800ac4692c0 ffff8800936d4a90
ffff8800352efd38 ffffffff8469a93e ffff8800352efd98 ffffffffc09b9b90
ffff8800352efd78 ffff8800ac4692c0 ffff8800b9c586c0 ffff8800831b6ab8
Call Trace:
[<ffffffff8469a93e>] ? mutex_unlock+0xe/0x10
[<ffffffffc09b9b90>] ? inet_diag_handler_get_info+0x110/0x1fb [inet_diag]
[<ffffffff845c868d>] netlink_broadcast+0x1d/0x20
[<ffffffff8469a93e>] ? mutex_unlock+0xe/0x10
[<ffffffff845b2bf5>] sock_diag_broadcast_destroy_work+0xd5/0x160
[<ffffffff8408ea97>] process_one_work+0x147/0x420
[<ffffffff8408f0f9>] worker_thread+0x69/0x470
[<ffffffff8409fda3>] ? preempt_count_sub+0xa3/0xf0
[<ffffffff8408f090>] ? rescuer_thread+0x320/0x320
[<ffffffff84093cd7>] kthread+0x107/0x120
[<ffffffff84093bd0>] ? kthread_create_on_node+0x1b0/0x1b0
[<ffffffff8469d31f>] ret_from_fork+0x3f/0x70
[<ffffffff84093bd0>] ? kthread_create_on_node+0x1b0/0x1b0
Tested:
Using a debug kernel while 'ss -E' is running:
ip netns add test-ns
ip netns delete test-ns
Fixes: eb4cb008529c sock_diag: define destruction multicast groups
Fixes: 26abe14379f8 net: Modify sk_alloc to not reference count the
netns of kernel sockets.
Reported-by: Dave Jones <da...@codemonkey.org.uk>
Suggested-by: Eric Dumazet <eric.duma...@gmail.com>
Signed-off-by: Craig Gallek <kr...@google.com>
---
net/core/sock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/sock.c b/net/core/sock.c
index e4be66f..08f16db 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1454,7 +1454,7 @@ void sk_destruct(struct sock *sk)
static void __sk_free(struct sock *sk)
{
- if (unlikely(sock_diag_has_destroy_listeners(sk)))
+ if (unlikely(sock_diag_has_destroy_listeners(sk) && sk->sk_net_refcnt))
sock_diag_broadcast_destroy(sk);
else
sk_destruct(sk);
--
2.2.0.rc0.207.ga3a616c
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