diff options
Diffstat (limited to 'drivers/s390/char/con3215.c')
| -rw-r--r-- | drivers/s390/char/con3215.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c index f356607835d8..4ae07c7e2175 100644 --- a/drivers/s390/char/con3215.c +++ b/drivers/s390/char/con3215.c @@ -771,35 +771,36 @@ static struct tty_driver *con3215_device(struct console *c, int *index) } /* - * panic() calls con3215_flush through a panic_notifier - * before the system enters a disabled, endless loop. + * The below function is called as a panic/reboot notifier before the + * system enters a disabled, endless loop. + * + * Notice we must use the spin_trylock() alternative, to prevent lockups + * in atomic context (panic routine runs with secondary CPUs, local IRQs + * and preemption disabled). */ -static void con3215_flush(void) +static int con3215_notify(struct notifier_block *self, + unsigned long event, void *data) { struct raw3215_info *raw; unsigned long flags; raw = raw3215[0]; /* console 3215 is the first one */ - spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags); + if (!spin_trylock_irqsave(get_ccwdev_lock(raw->cdev), flags)) + return NOTIFY_DONE; raw3215_make_room(raw, RAW3215_BUFFER_SIZE); spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags); -} -static int con3215_notify(struct notifier_block *self, - unsigned long event, void *data) -{ - con3215_flush(); - return NOTIFY_OK; + return NOTIFY_DONE; } static struct notifier_block on_panic_nb = { .notifier_call = con3215_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; static struct notifier_block on_reboot_nb = { .notifier_call = con3215_notify, - .priority = 0, + .priority = INT_MIN + 1, /* run the callback late */ }; /* |