On Tue, May 04, 2021 at 06:01:48PM +0200, Schrempf Frieder wrote:
> Since 8ce8c0abcba3 the driver queues work via priv->restart_work when
> resuming after suspend, even when the interface was not previously
> enabled. This causes a null dereference error as the workqueue is
> only allocated and initialized in mcp251x_open().
>
> To fix this we move the workqueue init to mcp251x_can_probe() as
> there is no reason to do it later and repeat it whenever
> mcp251x_open() is called.
AFAIU the IRQ is freed at ->ndo_stop() which is guaranteed to be called before
->remove(). If it's the case, we are fine.
FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Fixes: 8ce8c0abcba3 ("can: mcp251x: only reset hardware as required")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
> ---
> drivers/net/can/spi/mcp251x.c | 25 ++++++++++++++-----------
> 1 file changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
> index a57da43680d8..42e8e5791c9f 100644
> --- a/drivers/net/can/spi/mcp251x.c
> +++ b/drivers/net/can/spi/mcp251x.c
> @@ -956,8 +956,6 @@ static int mcp251x_stop(struct net_device *net)
>
> priv->force_quit = 1;
> free_irq(spi->irq, priv);
> - destroy_workqueue(priv->wq);
> - priv->wq = NULL;
>
> mutex_lock(&priv->mcp_lock);
>
> @@ -1224,15 +1222,6 @@ static int mcp251x_open(struct net_device *net)
> goto out_close;
> }
>
> - priv->wq = alloc_workqueue("mcp251x_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM,
> - 0);
> - if (!priv->wq) {
> - ret = -ENOMEM;
> - goto out_clean;
> - }
> - INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
> - INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);
> -
> ret = mcp251x_hw_wake(spi);
> if (ret)
> goto out_free_wq;
> @@ -1373,6 +1362,15 @@ static int mcp251x_can_probe(struct spi_device *spi)
> if (ret)
> goto out_clk;
>
> + priv->wq = alloc_workqueue("mcp251x_wq", WQ_FREEZABLE | WQ_MEM_RECLAIM,
> + 0);
> + if (!priv->wq) {
> + ret = -ENOMEM;
> + goto out_clk;
> + }
> + INIT_WORK(&priv->tx_work, mcp251x_tx_work_handler);
> + INIT_WORK(&priv->restart_work, mcp251x_restart_work_handler);
> +
> priv->spi = spi;
> mutex_init(&priv->mcp_lock);
>
> @@ -1417,6 +1415,8 @@ static int mcp251x_can_probe(struct spi_device *spi)
> return 0;
>
> error_probe:
> + destroy_workqueue(priv->wq);
> + priv->wq = NULL;
> mcp251x_power_enable(priv->power, 0);
>
> out_clk:
> @@ -1438,6 +1438,9 @@ static int mcp251x_can_remove(struct spi_device *spi)
>
> mcp251x_power_enable(priv->power, 0);
>
> + destroy_workqueue(priv->wq);
> + priv->wq = NULL;
> +
> clk_disable_unprepare(priv->clk);
>
> free_candev(net);
> --
> 2.25.1
>
>
--
With Best Regards,
Andy Shevchenko
