From 19fa6e601b251f13400767813372944b3e2f444b Mon Sep 17 00:00:00 2001 From: Denis Kirjanov Date: Thu, 30 Mar 2017 10:06:19 -0400 Subject: [PATCH] tty/hvc_console: fix console lock ordering with spinlock hvc_remove() takes a spin lock first then acquires the console semaphore. This situation can easily lead to a deadlock scenario where we call scheduler with spin lock held. Signed-off-by: Denis Kirjanov Signed-off-by: Greg Kroah-Hartman --- drivers/tty/hvc/hvc_console.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c index b19ae36a05ec..a8d399188242 100644 --- a/drivers/tty/hvc/hvc_console.c +++ b/drivers/tty/hvc/hvc_console.c @@ -920,17 +920,17 @@ int hvc_remove(struct hvc_struct *hp) tty = tty_port_tty_get(&hp->port); + console_lock(); spin_lock_irqsave(&hp->lock, flags); if (hp->index < MAX_NR_HVC_CONSOLES) { - console_lock(); vtermnos[hp->index] = -1; cons_ops[hp->index] = NULL; - console_unlock(); } /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ spin_unlock_irqrestore(&hp->lock, flags); + console_unlock(); /* * We 'put' the instance that was grabbed when the kref instance -- 2.20.1