Commit 5d0fdf1e authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
Browse files

tty_io: fix remaining pid struct locking 



This fixes the last couple of pid struct locking failures I know about.

[oleg@tv-sign.ru: clean up do_task_stat()]
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 575537b3

drivers/char/tty_io.c

+27 −1
Original line number Diff line number Diff line
@@ -3173,6 +3173,27 @@ static int tiocsctty(struct tty_struct *tty, int arg) 
	return ret;

}



/**

 *	tty_get_pgrp	-	return a ref counted pgrp pid

 *	@tty: tty to read

 *

 *	Returns a refcounted instance of the pid struct for the process

 *	group controlling the tty.

 */



struct pid *tty_get_pgrp(struct tty_struct *tty)

{

	unsigned long flags;

	struct pid *pgrp;



	spin_lock_irqsave(&tty->ctrl_lock, flags);

	pgrp = get_pid(tty->pgrp);

	spin_unlock_irqrestore(&tty->ctrl_lock, flags);



	return pgrp;

}

EXPORT_SYMBOL_GPL(tty_get_pgrp);



/**

 *	tiocgpgrp		-	get process group

 *	@tty: tty passed by user
@@ -3187,13 +3208,18 @@ static int tiocsctty(struct tty_struct *tty, int arg) 


static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)

{

	struct pid *pid;

	int ret;

	/*

	 * (tty == real_tty) is a cheap way of

	 * testing if the tty is NOT a master pty.

	 */

	if (tty == real_tty && current->signal->tty != real_tty)

		return -ENOTTY;

	return put_user(pid_vnr(real_tty->pgrp), p);

	pid = tty_get_pgrp(real_tty);

	ret =  put_user(pid_vnr(pid), p);

	put_pid(pid);

	return ret;

}



/**

fs/proc/array.c

+3 −1
Original line number Diff line number Diff line
@@ -429,7 +429,9 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 
		struct signal_struct *sig = task->signal;



		if (sig->tty) {

			tty_pgrp = pid_nr_ns(sig->tty->pgrp, ns);

			struct pid *pgrp = tty_get_pgrp(sig->tty);

			tty_pgrp = pid_nr_ns(pgrp, ns);

			put_pid(pgrp);

			tty_nr = new_encode_dev(tty_devnum(sig->tty));

		}

include/linux/tty.h

+1 −0
Original line number Diff line number Diff line
@@ -297,6 +297,7 @@ extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp, 
extern void tty_write_message(struct tty_struct *tty, char *msg);



extern int is_current_pgrp_orphaned(void);

extern struct pid *tty_get_pgrp(struct tty_struct *tty);

extern int is_ignored(int sig);

extern int tty_signal(int sig, struct tty_struct *tty);

extern void tty_hangup(struct tty_struct * tty);