From f5e3bcc504c3c35cc6e06a9ee42efed7c274066b Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Fri, 29 Jun 2012 14:48:36 +0100 Subject: tty: localise the lock The termios and other changes mean the other protections needed on the driver tty arrays should be adequate. Turn it all back on. This contains pieces folded in from the fixes made to the original patches | From: Geert Uytterhoeven (fix m68k) | From: Paul Gortmaker (fix cris) | From: Jiri Kosina (lockdep) | From: Eric Dumazet (lockdep) Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_mutex.c | 71 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 56 insertions(+), 15 deletions(-) (limited to 'drivers/tty/tty_mutex.c') diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 9ff986c32a21..67feac9e6ebb 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -4,29 +4,70 @@ #include #include -/* - * The 'big tty mutex' - * - * This mutex is taken and released by tty_lock() and tty_unlock(), - * replacing the older big kernel lock. - * It can no longer be taken recursively, and does not get - * released implicitly while sleeping. - * - * Don't use in new code. - */ -static DEFINE_MUTEX(big_tty_mutex); +/* Legacy tty mutex glue */ + +enum { + TTY_MUTEX_NORMAL, + TTY_MUTEX_NESTED, +}; /* * Getting the big tty mutex. */ -void __lockfunc tty_lock(void) + +static void __lockfunc tty_lock_nested(struct tty_struct *tty, + unsigned int subclass) { - mutex_lock(&big_tty_mutex); + if (tty->magic != TTY_MAGIC) { + printk(KERN_ERR "L Bad %p\n", tty); + WARN_ON(1); + return; + } + tty_kref_get(tty); + mutex_lock_nested(&tty->legacy_mutex, subclass); +} + +void __lockfunc tty_lock(struct tty_struct *tty) +{ + return tty_lock_nested(tty, TTY_MUTEX_NORMAL); } EXPORT_SYMBOL(tty_lock); -void __lockfunc tty_unlock(void) +void __lockfunc tty_unlock(struct tty_struct *tty) { - mutex_unlock(&big_tty_mutex); + if (tty->magic != TTY_MAGIC) { + printk(KERN_ERR "U Bad %p\n", tty); + WARN_ON(1); + return; + } + mutex_unlock(&tty->legacy_mutex); + tty_kref_put(tty); } EXPORT_SYMBOL(tty_unlock); + +/* + * Getting the big tty mutex for a pair of ttys with lock ordering + * On a non pty/tty pair tty2 can be NULL which is just fine. + */ +void __lockfunc tty_lock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + if (tty < tty2) { + tty_lock(tty); + tty_lock_nested(tty2, TTY_MUTEX_NESTED); + } else { + if (tty2 && tty2 != tty) + tty_lock(tty2); + tty_lock_nested(tty, TTY_MUTEX_NESTED); + } +} +EXPORT_SYMBOL(tty_lock_pair); + +void __lockfunc tty_unlock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + tty_unlock(tty); + if (tty2 && tty2 != tty) + tty_unlock(tty2); +} +EXPORT_SYMBOL(tty_unlock_pair); -- cgit v1.2.3 From 6d31a88cb2e01d46c0cb74aa5da529e1f92ae3db Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Sat, 14 Jul 2012 15:31:27 +0100 Subject: tty: revert incorrectly applied lock patch I sent GregKH this after the pre-requisites. He dropped the pre-requesites for good reason and unfortunately then applied this patch. Without this reverted you get random kernel memory corruption which will make bisecting anything between it and the properly applied patches a complete sod. Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_mutex.c | 71 +++++++++++-------------------------------------- 1 file changed, 15 insertions(+), 56 deletions(-) (limited to 'drivers/tty/tty_mutex.c') diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 67feac9e6ebb..9ff986c32a21 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -4,70 +4,29 @@ #include #include -/* Legacy tty mutex glue */ - -enum { - TTY_MUTEX_NORMAL, - TTY_MUTEX_NESTED, -}; +/* + * The 'big tty mutex' + * + * This mutex is taken and released by tty_lock() and tty_unlock(), + * replacing the older big kernel lock. + * It can no longer be taken recursively, and does not get + * released implicitly while sleeping. + * + * Don't use in new code. + */ +static DEFINE_MUTEX(big_tty_mutex); /* * Getting the big tty mutex. */ - -static void __lockfunc tty_lock_nested(struct tty_struct *tty, - unsigned int subclass) +void __lockfunc tty_lock(void) { - if (tty->magic != TTY_MAGIC) { - printk(KERN_ERR "L Bad %p\n", tty); - WARN_ON(1); - return; - } - tty_kref_get(tty); - mutex_lock_nested(&tty->legacy_mutex, subclass); -} - -void __lockfunc tty_lock(struct tty_struct *tty) -{ - return tty_lock_nested(tty, TTY_MUTEX_NORMAL); + mutex_lock(&big_tty_mutex); } EXPORT_SYMBOL(tty_lock); -void __lockfunc tty_unlock(struct tty_struct *tty) +void __lockfunc tty_unlock(void) { - if (tty->magic != TTY_MAGIC) { - printk(KERN_ERR "U Bad %p\n", tty); - WARN_ON(1); - return; - } - mutex_unlock(&tty->legacy_mutex); - tty_kref_put(tty); + mutex_unlock(&big_tty_mutex); } EXPORT_SYMBOL(tty_unlock); - -/* - * Getting the big tty mutex for a pair of ttys with lock ordering - * On a non pty/tty pair tty2 can be NULL which is just fine. - */ -void __lockfunc tty_lock_pair(struct tty_struct *tty, - struct tty_struct *tty2) -{ - if (tty < tty2) { - tty_lock(tty); - tty_lock_nested(tty2, TTY_MUTEX_NESTED); - } else { - if (tty2 && tty2 != tty) - tty_lock(tty2); - tty_lock_nested(tty, TTY_MUTEX_NESTED); - } -} -EXPORT_SYMBOL(tty_lock_pair); - -void __lockfunc tty_unlock_pair(struct tty_struct *tty, - struct tty_struct *tty2) -{ - tty_unlock(tty); - if (tty2 && tty2 != tty) - tty_unlock(tty2); -} -EXPORT_SYMBOL(tty_unlock_pair); -- cgit v1.2.3 From 89c8d91e31f267703e365593f6bfebb9f6d2ad01 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 8 Aug 2012 16:30:13 +0100 Subject: tty: localise the lock The termios and other changes mean the other protections needed on the driver tty arrays should be adequate. Turn it all back on. This contains pieces folded in from the fixes made to the original patches | From: Geert Uytterhoeven (fix m68k) | From: Paul Gortmaker (fix cris) | From: Jiri Kosina (lockdep) | From: Eric Dumazet (lockdep) Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_mutex.c | 71 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 56 insertions(+), 15 deletions(-) (limited to 'drivers/tty/tty_mutex.c') diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 9ff986c32a21..67feac9e6ebb 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -4,29 +4,70 @@ #include #include -/* - * The 'big tty mutex' - * - * This mutex is taken and released by tty_lock() and tty_unlock(), - * replacing the older big kernel lock. - * It can no longer be taken recursively, and does not get - * released implicitly while sleeping. - * - * Don't use in new code. - */ -static DEFINE_MUTEX(big_tty_mutex); +/* Legacy tty mutex glue */ + +enum { + TTY_MUTEX_NORMAL, + TTY_MUTEX_NESTED, +}; /* * Getting the big tty mutex. */ -void __lockfunc tty_lock(void) + +static void __lockfunc tty_lock_nested(struct tty_struct *tty, + unsigned int subclass) { - mutex_lock(&big_tty_mutex); + if (tty->magic != TTY_MAGIC) { + printk(KERN_ERR "L Bad %p\n", tty); + WARN_ON(1); + return; + } + tty_kref_get(tty); + mutex_lock_nested(&tty->legacy_mutex, subclass); +} + +void __lockfunc tty_lock(struct tty_struct *tty) +{ + return tty_lock_nested(tty, TTY_MUTEX_NORMAL); } EXPORT_SYMBOL(tty_lock); -void __lockfunc tty_unlock(void) +void __lockfunc tty_unlock(struct tty_struct *tty) { - mutex_unlock(&big_tty_mutex); + if (tty->magic != TTY_MAGIC) { + printk(KERN_ERR "U Bad %p\n", tty); + WARN_ON(1); + return; + } + mutex_unlock(&tty->legacy_mutex); + tty_kref_put(tty); } EXPORT_SYMBOL(tty_unlock); + +/* + * Getting the big tty mutex for a pair of ttys with lock ordering + * On a non pty/tty pair tty2 can be NULL which is just fine. + */ +void __lockfunc tty_lock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + if (tty < tty2) { + tty_lock(tty); + tty_lock_nested(tty2, TTY_MUTEX_NESTED); + } else { + if (tty2 && tty2 != tty) + tty_lock(tty2); + tty_lock_nested(tty, TTY_MUTEX_NESTED); + } +} +EXPORT_SYMBOL(tty_lock_pair); + +void __lockfunc tty_unlock_pair(struct tty_struct *tty, + struct tty_struct *tty2) +{ + tty_unlock(tty); + if (tty2 && tty2 != tty) + tty_unlock(tty2); +} +EXPORT_SYMBOL(tty_unlock_pair); -- cgit v1.2.3