dlm for 4.14

This set includes a bunch of minor code cleanups that
have accumulated, probably from code analyzers people
like to run.  There is one nice fix that avoids some
socket leaks by switching to use sock_create_lite().
dlm: use sock_create_lite inside tcp_accept_from_sock

With commit 0ffdaf5b41cf ("net/sock: add WARN_ON(parent->sk)
in sock_graft()"), a calltrace happened as follows:

[  457.018340] WARNING: CPU: 0 PID: 15623 at ./include/net/sock.h:1703 inet_accept+0x135/0x140
...
[  457.018381] RIP: 0010:inet_accept+0x135/0x140
[  457.018381] RSP: 0018:ffffc90001727d18 EFLAGS: 00010286
[  457.018383] RAX: 0000000000000001 RBX: ffff880012413000 RCX: 0000000000000001
[  457.018384] RDX: 000000000000018a RSI: 00000000fffffe01 RDI: ffffffff8156fae8
[  457.018384] RBP: ffffc90001727d38 R08: 0000000000000000 R09: 0000000000004305
[  457.018385] R10: 0000000000000001 R11: 0000000000004304 R12: ffff880035ae7a00
[  457.018386] R13: ffff88001282af10 R14: ffff880034e4e200 R15: 0000000000000000
[  457.018387] FS:  0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
[  457.018388] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  457.018389] CR2: 00007fdec22f9000 CR3: 0000000002b5a000 CR4: 00000000000006f0
[  457.018395] Call Trace:
[  457.018402]  tcp_accept_from_sock.part.8+0x12d/0x449 [dlm]
[  457.018405]  ? vprintk_emit+0x248/0x2d0
[  457.018409]  tcp_accept_from_sock+0x3f/0x50 [dlm]
[  457.018413]  process_recv_sockets+0x3b/0x50 [dlm]
[  457.018415]  process_one_work+0x138/0x370
[  457.018417]  worker_thread+0x4d/0x3b0
[  457.018419]  kthread+0x109/0x140
[  457.018421]  ? rescuer_thread+0x320/0x320
[  457.018422]  ? kthread_park+0x60/0x60
[  457.018424]  ret_from_fork+0x25/0x30

Since newsocket created by sock_create_kern sets it's
sock by the path:

	sock_create_kern -> __sock_creat
			 ->pf->create => inet_create
			 -> sock_init_data

Then WARN_ON is triggered by "con->sock->ops->accept =>
inet_accept -> sock_graft", it also means newsock->sk
is leaked since sock_graft will replace it with a new
sk.

To resolve the issue, we need to use sock_create_lite
instead of sock_create_kern, like commit 0933a578cd55
("rds: tcp: use sock_create_lite() to create the accept
socket") did.

Reported-by: Zhilong Liu <zlliu@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>
1 file changed