can: slcan: Fix spinlock variant (367525c8) · Commits · 戴 / test

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:

Alexander Stein <alexander.stein@systec-electronic.com> Acked-by:

Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by:

Marc Kleine-Budde <mkl@pengutronix.de>

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. */

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