Commit c389d27b authored by Borislav Petkov's avatar Borislav Petkov Committed by Linus Torvalds

8250.c: port.lock is irq-safe

serial8250_startup() doesn't disable interrupts while taking the &up->port.lock
which might race against the interrupt handler serial8250_interrupt(), which
when entered, will deadlock waiting for the lock to be released.
Signed-off-by: default avatarBorislav Petkov <petkovbb@gmail.com>
Tested-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5def9a3a
......@@ -1885,7 +1885,7 @@ static int serial8250_startup(struct uart_port *port)
* the interrupt is enabled. Delays are necessary to
* allow register changes to become visible.
*/
spin_lock(&up->port.lock);
spin_lock_irqsave(&up->port.lock, flags);
if (up->port.flags & UPF_SHARE_IRQ)
disable_irq_nosync(up->port.irq);
......@@ -1901,7 +1901,7 @@ static int serial8250_startup(struct uart_port *port)
if (up->port.flags & UPF_SHARE_IRQ)
enable_irq(up->port.irq);
spin_unlock(&up->port.lock);
spin_unlock_irqrestore(&up->port.lock, flags);
/*
* If the interrupt is not reasserted, setup a timer to
......
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