Attachment #28091 for bug #65372

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Lines 918-926 Link Here

(-)a/drivers/char/tty_io.c (-10 / +29 lines)
918		918
919	lock_kernel();	919	lock_kernel();
920		920
		921	down(&tty_sem);
921	tty = current->signal->tty;	922	tty = current->signal->tty;
922	if (tty) {	923	if (tty) {
923	tty_pgrp = tty->pgrp;	924	tty_pgrp = tty->pgrp;
		925	up(&tty_sem);
924	if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)	926	if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
925	tty_vhangup(tty);	927	tty_vhangup(tty);
926	} else {	928	} else {
Lines 928-933 Link Here
928	kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit);	930	kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit);
929	kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit);	931	kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit);
930	}	932	}
		933	up(&tty_sem);
931	unlock_kernel();	934	unlock_kernel();
932	return;	935	return;
933	}	936	}
Lines 937-951 Link Here
937	kill_pg(tty_pgrp, SIGCONT, on_exit);	940	kill_pg(tty_pgrp, SIGCONT, on_exit);
938	}	941	}
939		942
		943	/* Must lock changes to tty_old_pgrp */
		944	down(&tty_sem);
940	current->signal->tty_old_pgrp = 0;	945	current->signal->tty_old_pgrp = 0;
941	tty->session = 0;	946	tty->session = 0;
942	tty->pgrp = -1;	947	tty->pgrp = -1;
943		948
		949	/* Now clear signal->tty under the lock */
944	read_lock(&tasklist_lock);	950	read_lock(&tasklist_lock);
945	do_each_task_pid(current->signal->session, PIDTYPE_SID, p) {	951	do_each_task_pid(current->signal->session, PIDTYPE_SID, p) {
946	p->signal->tty = NULL;	952	p->signal->tty = NULL;
947	} while_each_task_pid(current->signal->session, PIDTYPE_SID, p);	953	} while_each_task_pid(current->signal->session, PIDTYPE_SID, p);
948	read_unlock(&tasklist_lock);	954	read_unlock(&tasklist_lock);
		955	up(&tty_sem);
949	unlock_kernel();	956	unlock_kernel();
950	}	957	}
951		958
Lines 1172-1183 Link Here
1172	struct termios ltp, ltp_loc, o_ltp, **o_ltp_loc;	1179	struct termios ltp, ltp_loc, o_ltp, **o_ltp_loc;
1173	int retval=0;	1180	int retval=0;
1174		1181
1175	/*
1176	* Check whether we need to acquire the tty semaphore to avoid
1177	* race conditions. For now, play it safe.
1178	*/
1179	down(&tty_sem);
1180
1181	/* check whether we're reopening an existing tty */	1182	/* check whether we're reopening an existing tty */
1182	if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {	1183	if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1183	tty = devpts_get_tty(idx);	1184	tty = devpts_get_tty(idx);
Lines 1366-1372 Link Here
1366		1367
1367	/* All paths come through here to release the semaphore */	1368	/* All paths come through here to release the semaphore */
1368	end_init:	1369	end_init:
1369	up(&tty_sem);
1370	return retval;	1370	return retval;
1371		1371
1372	/* Release locally allocated memory ... nothing placed in slots */	1372	/* Release locally allocated memory ... nothing placed in slots */
Lines 1562-1570 Link Here
1562	* each iteration we avoid any problems.	1562	* each iteration we avoid any problems.
1563	*/	1563	*/
1564	while (1) {	1564	while (1) {
		1565	/* Guard against races with tty->count changes elsewhere and
		1566	opens on /dev/tty */
		1567
		1568	down(&tty_sem);
1565	tty_closing = tty->count <= 1;	1569	tty_closing = tty->count <= 1;
1566	o_tty_closing = o_tty &&	1570	o_tty_closing = o_tty &&
1567	(o_tty->count <= (pty_master ? 1 : 0));	1571	(o_tty->count <= (pty_master ? 1 : 0));
		1572	up(&tty_sem);
1568	do_sleep = 0;	1573	do_sleep = 0;
1569		1574
1570	if (tty_closing) {	1575	if (tty_closing) {
Lines 1600-1605 Link Here
1600	* both sides, and we've completed the last operation that could	1605	* both sides, and we've completed the last operation that could
1601	* block, so it's safe to proceed with closing.	1606	* block, so it's safe to proceed with closing.
1602	*/	1607	*/
		1608
		1609	down(&tty_sem);
1603	if (pty_master) {	1610	if (pty_master) {
1604	if (--o_tty->count < 0) {	1611	if (--o_tty->count < 0) {
1605	printk(KERN_WARNING "release_dev: bad pty slave count "	1612	printk(KERN_WARNING "release_dev: bad pty slave count "
Lines 1613-1619 Link Here
1613	tty->count, tty_name(tty, buf));	1620	tty->count, tty_name(tty, buf));
1614	tty->count = 0;	1621	tty->count = 0;
1615	}	1622	}
1616		1623	up(&tty_sem);
		1624
1617	/*	1625	/*
1618	* We've decremented tty->count, so we need to remove this file	1626	* We've decremented tty->count, so we need to remove this file
1619	* descriptor off the tty->tty_files list; this serves two	1627	* descriptor off the tty->tty_files list; this serves two
Lines 1760-1769 Link Here
1760	noctty = filp->f_flags & O_NOCTTY;	1768	noctty = filp->f_flags & O_NOCTTY;
1761	index = -1;	1769	index = -1;
1762	retval = 0;	1770	retval = 0;
		1771
		1772	down(&tty_sem);
1763		1773
1764	if (device == MKDEV(TTYAUX_MAJOR,0)) {	1774	if (device == MKDEV(TTYAUX_MAJOR,0)) {
1765	if (!current->signal->tty)	1775	if (!current->signal->tty) {
		1776	up(&tty_sem);
1766	return -ENXIO;	1777	return -ENXIO;
		1778	}
1767	driver = current->signal->tty->driver;	1779	driver = current->signal->tty->driver;
1768	index = current->signal->tty->index;	1780	index = current->signal->tty->index;
1769	filp->f_flags \|= O_NONBLOCK; /* Don't let /dev/tty block */	1781	filp->f_flags \|= O_NONBLOCK; /* Don't let /dev/tty block */
Lines 1788-1801 Link Here
1788	noctty = 1;	1800	noctty = 1;
1789	goto got_driver;	1801	goto got_driver;
1790	}	1802	}
		1803	up(&tty_sem);
1791	return -ENODEV;	1804	return -ENODEV;
1792	}	1805	}
1793		1806
1794	driver = get_tty_driver(device, &index);	1807	driver = get_tty_driver(device, &index);
1795	if (!driver)	1808	if (!driver) {
		1809	up(&tty_sem);
1796	return -ENODEV;	1810	return -ENODEV;
		1811	}
1797	got_driver:	1812	got_driver:
1798	retval = init_dev(driver, index, &tty);	1813	retval = init_dev(driver, index, &tty);
		1814	up(&tty_sem);
1799	if (retval)	1815	if (retval)
1800	return retval;	1816	return retval;
1801		1817
Lines 1881-1887 Link Here
1881	}	1897	}
1882	up(&allocated_ptys_lock);	1898	up(&allocated_ptys_lock);
1883		1899
		1900	down(&tty_sem);
1884	retval = init_dev(ptm_driver, index, &tty);	1901	retval = init_dev(ptm_driver, index, &tty);
		1902	up(&tty_sem);
		1903
1885	if (retval)	1904	if (retval)
1886	goto out;	1905	goto out;
1887		1906

Lines 332-338 Link Here

(-)a/kernel/exit.c (+2 lines)
332	exit_mm(current);	332	exit_mm(current);
333		333
334	set_special_pids(1, 1);	334	set_special_pids(1, 1);
		335	down(&tty_sem);
335	current->signal->tty = NULL;	336	current->signal->tty = NULL;
		337	up(&tty_sem);
336		338
337	/* Block and flush all signals */	339	/* Block and flush all signals */
338	sigfillset(&blocked);	340	sigfillset(&blocked);

Lines 1075-1080 Link Here

(-)a/kernel/sys.c (+2 lines)
1075	if (!thread_group_leader(current))	1075	if (!thread_group_leader(current))
1076	return -EINVAL;	1076	return -EINVAL;
1077		1077
		1078	down(&tty_sem);
1078	write_lock_irq(&tasklist_lock);	1079	write_lock_irq(&tasklist_lock);
1079		1080
1080	pid = find_pid(PIDTYPE_PGID, current->pid);	1081	pid = find_pid(PIDTYPE_PGID, current->pid);
Lines 1088-1093 Link Here
1088	err = process_group(current);	1089	err = process_group(current);
1089	out:	1090	out:
1090	write_unlock_irq(&tasklist_lock);	1091	write_unlock_irq(&tasklist_lock);
		1092	up(&tty_sem);
1091	return err;	1093	return err;
1092	}	1094	}
1093		1095

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