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Commit 367525c8 authored by Alexander Stein's avatar Alexander Stein Committed by Marc Kleine-Budde
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can: slcan: Fix spinlock variant 



slc_xmit is called within softirq context and locks sl->lock, but
slcan_write_wakeup is not softirq context, so we need to use
spin_[un]lock_bh!
Detected using kernel lock debugging mechanism.

Signed-off-by: default avatarAlexander Stein <alexander.stein@systec-electronic.com>
Acked-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent d4824432

drivers/net/can/slcan.c

+3 −3
Original line number Diff line number Diff line
@@ -322,13 +322,13 @@ static void slcan_write_wakeup(struct tty_struct *tty) 
	if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))

		return;



	spin_lock(&sl->lock);

	spin_lock_bh(&sl->lock);

	if (sl->xleft <= 0)  {

		/* Now serial buffer is almost free & we can start

		 * transmission of another packet */

		sl->dev->stats.tx_packets++;

		clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);

		spin_unlock(&sl->lock);

		spin_unlock_bh(&sl->lock);

		netif_wake_queue(sl->dev);

		return;

	}
@@ -336,7 +336,7 @@ static void slcan_write_wakeup(struct tty_struct *tty) 
	actual = tty->ops->write(tty, sl->xhead, sl->xleft);

	sl->xleft -= actual;

	sl->xhead += actual;

	spin_unlock(&sl->lock);

	spin_unlock_bh(&sl->lock);

}



/* Send a can_frame to a TTY queue. */