diff options
| author | Duoming Zhou <duoming@zju.edu.cn> | 2022-04-25 12:24:00 +0800 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2022-04-29 12:09:19 +0200 |
| commit | 47f070a63e735bcc8d481de31be1b5a1aa62b31c (patch) | |
| tree | f385a5fbed2d7b79da328eedd6c8ddcea9522ee7 | |
| parent | 72ed3ee9fa0b461ad086403a8b5336154bd82234 (diff) | |
| download | linux-47f070a63e735bcc8d481de31be1b5a1aa62b31c.tar.bz2 | |
can: grcan: grcan_close(): fix deadlock
There are deadlocks caused by del_timer_sync(&priv->hang_timer) and
del_timer_sync(&priv->rr_timer) in grcan_close(), one of the deadlocks
are shown below:
(Thread 1) | (Thread 2)
| grcan_reset_timer()
grcan_close() | mod_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | grcan_initiate_running_reset()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold priv->lock in position (1) of thread 1 and use
del_timer_sync() to wait timer to stop, but timer handler also need
priv->lock in position (2) of thread 2. As a result, grcan_close()
will block forever.
This patch extracts del_timer_sync() from the protection of
spin_lock_irqsave(), which could let timer handler to obtain the
needed lock.
Link: https://lore.kernel.org/all/20220425042400.66517-1-duoming@zju.edu.cn
Fixes: 6cec9b07fe6a ("can: grcan: Add device driver for GRCAN and GRHCAN cores")
Cc: stable@vger.kernel.org
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
| -rw-r--r-- | drivers/net/can/grcan.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c index d0c5a7a60daf..1189057b5d68 100644 --- a/drivers/net/can/grcan.c +++ b/drivers/net/can/grcan.c @@ -1102,8 +1102,10 @@ static int grcan_close(struct net_device *dev) priv->closing = true; if (priv->need_txbug_workaround) { + spin_unlock_irqrestore(&priv->lock, flags); del_timer_sync(&priv->hang_timer); del_timer_sync(&priv->rr_timer); + spin_lock_irqsave(&priv->lock, flags); } netif_stop_queue(dev); grcan_stop_hardware(dev); |