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authorPatrick Donnelly <batrick@batbytes.com>2015-07-13 01:51:52 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-07-24 03:56:38 +0300
commit6719693ca2efb0f04654d05768ee299e87e1694b (patch)
tree08cc78496b9c1251dc21d2f52a8f995b955f8b81 /drivers/tty/tty_io.c
parentda891641b6c92e260966dfce3dd93111d08656c8 (diff)
downloadlinux-6719693ca2efb0f04654d05768ee299e87e1694b.tar.xz
tty: add missing rcu_read_lock for task_pgrp
task_pgrp requires an rcu or tasklist lock to be obtained if the returned pid is to be dereferenced, which kill_pgrp does. Obtain an RCU lock for the duration of use. Signed-off-by: Patrick Donnelly <batrick@batbytes.com> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r--drivers/tty/tty_io.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 57fc6ee12332..6bdfb98bf020 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -388,33 +388,40 @@ EXPORT_SYMBOL_GPL(tty_find_polling_driver);
int tty_check_change(struct tty_struct *tty)
{
unsigned long flags;
+ struct pid *pgrp;
int ret = 0;
if (current->signal->tty != tty)
return 0;
+ rcu_read_lock();
+ pgrp = task_pgrp(current);
+
spin_lock_irqsave(&tty->ctrl_lock, flags);
if (!tty->pgrp) {
printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
goto out_unlock;
}
- if (task_pgrp(current) == tty->pgrp)
+ if (pgrp == tty->pgrp)
goto out_unlock;
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+
if (is_ignored(SIGTTOU))
- goto out;
+ goto out_rcuunlock;
if (is_current_pgrp_orphaned()) {
ret = -EIO;
- goto out;
+ goto out_rcuunlock;
}
- kill_pgrp(task_pgrp(current), SIGTTOU, 1);
+ kill_pgrp(pgrp, SIGTTOU, 1);
+ rcu_read_unlock();
set_thread_flag(TIF_SIGPENDING);
ret = -ERESTARTSYS;
-out:
return ret;
out_unlock:
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+out_rcuunlock:
+ rcu_read_unlock();
return ret;
}