forked from Minki/linux
e9036d0662
When the tty lock is interrupted on attempted re-open, 2 tty krefs
are still held. Drop extra kref before returning failure from
tty_lock_interruptible(), and drop lookup kref before returning
failure from tty_open().
Fixes: 0bfd464d3f ("tty: Wait interruptibly for tty lock on reopen")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
60 lines
1.2 KiB
C
60 lines
1.2 KiB
C
#include <linux/tty.h>
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/semaphore.h>
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#include <linux/sched.h>
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/* Legacy tty mutex glue */
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/*
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* Getting the big tty mutex.
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*/
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void __lockfunc tty_lock(struct tty_struct *tty)
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{
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if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
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return;
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tty_kref_get(tty);
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mutex_lock(&tty->legacy_mutex);
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}
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EXPORT_SYMBOL(tty_lock);
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int tty_lock_interruptible(struct tty_struct *tty)
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{
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int ret;
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if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
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return -EIO;
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tty_kref_get(tty);
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ret = mutex_lock_interruptible(&tty->legacy_mutex);
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if (ret)
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tty_kref_put(tty);
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return ret;
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}
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void __lockfunc tty_unlock(struct tty_struct *tty)
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{
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if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty))
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return;
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mutex_unlock(&tty->legacy_mutex);
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tty_kref_put(tty);
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}
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EXPORT_SYMBOL(tty_unlock);
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void __lockfunc tty_lock_slave(struct tty_struct *tty)
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{
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if (tty && tty != tty->link)
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tty_lock(tty);
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}
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void __lockfunc tty_unlock_slave(struct tty_struct *tty)
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{
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if (tty && tty != tty->link)
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tty_unlock(tty);
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}
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void tty_set_lock_subclass(struct tty_struct *tty)
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{
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lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);
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}
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