pid: fix lockdep deadlock warning due to ucount_lock

=========================================================
[ INFO: possible irq lock inversion dependency detected ]
4.10.0-rc2-00024-g4aecec9-dirty #118 Tainted: G        W
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swapper/1/0 just changed the state of lock:
 (&(&sighand->siglock)->rlock){-.....}, at: [<ffffffffbd0a1bc6>] __lock_task_sighand+0xb6/0x2c0
but this lock took another, HARDIRQ-unsafe lock in the past:
 (ucounts_lock){+.+...}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Chain exists of:                 &(&sighand->siglock)->rlock --> &(&tty->ctrl_lock)->rlock --> ucounts_lock
 Possible interrupt unsafe locking scenario:
       CPU0                    CPU1
       ----                    ----
  lock(ucounts_lock);
                               local_irq_disable();
                               lock(&(&sighand->siglock)->rlock);
                               lock(&(&tty->ctrl_lock)->rlock);
  <Interrupt>
    lock(&(&sighand->siglock)->rlock);

 *** DEADLOCK ***

This patch removes a dependency between rlock and ucount_lock.

Fixes: f333c700c610 ("pidns: Add a limit on the number of pid namespaces")
Cc: stable@vger.kernel.org
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

path: root/include/net/gtp.h

#ifndef _GTP_H_
#define _GTP_H_

/* General GTP protocol related definitions. */

#define GTP0_PORT	3386
#define GTP1U_PORT	2152

#define GTP_TPDU	255

struct gtp0_header {	/* According to GSM TS 09.60. */
	__u8	flags;
	__u8	type;
	__be16	length;
	__be16	seq;
	__be16	flow;
	__u8	number;
	__u8	spare[3];
	__be64	tid;
} __attribute__ ((packed));

struct gtp1_header {	/* According to 3GPP TS 29.060. */
	__u8	flags;
	__u8	type;
	__be16	length;
	__be32	tid;
} __attribute__ ((packed));

#define GTP1_F_NPDU	0x01
#define GTP1_F_SEQ	0x02
#define GTP1_F_EXTHDR	0x04
#define GTP1_F_MASK	0x07

#endif