2021-05-04 17:05:47

by Frieder Schrempf

[permalink] [raw]
Subject: [PATCH] can: mcp251x: Fix resume from sleep before interface was brought up

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.

Fixes: 8ce8c0abcba3 ("can: mcp251x: only reset hardware as required")
Cc: [email protected]
Signed-off-by: Frieder Schrempf <[email protected]>
---
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



2021-05-04 19:51:18

by Schlüßler, Timo

[permalink] [raw]
Subject: Re: [PATCH] can: mcp251x: Fix resume from sleep before interface was brought up

> On 04.05.2021 18:01:48, Schrempf Frieder wrote:
>> Fixes: 8ce8c0abcba3 ("can: mcp251x: only reset hardware as required")
>> Cc: [email protected]
>> Signed-off-by: Frieder Schrempf <[email protected]>

Thanks for finding and fixing this and sorry for introducing the bug.

Regards
Timo

2021-05-04 21:40:52

by Marc Kleine-Budde

[permalink] [raw]
Subject: Re: [PATCH] can: mcp251x: Fix resume from sleep before interface was brought up

On 04.05.2021 18:01:48, 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.
>
> Fixes: 8ce8c0abcba3 ("can: mcp251x: only reset hardware as required")
> Cc: [email protected]
> Signed-off-by: Frieder Schrempf <[email protected]>

Added to linux-can/testing.

Thanks,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |

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