Re: [PATCH] drivers core: Fix oops when driver probe fails

[Greg KH]

On Tue, Jul 27, 2021 at 12:40:35PM +0200, Filip Schauer wrote:
> dma_range_map is freed to early, which might cause an oops when
> a driver probe fails.
>  Call trace:
>   is_free_buddy_page+0xe4/0x1d4
>   __free_pages+0x2c/0x88
>   dma_free_contiguous+0x64/0x80
>   dma_direct_free+0x38/0xb4
>   dma_free_attrs+0x88/0xa0
>   dmam_release+0x28/0x34
>   release_nodes+0x78/0x8c
>   devres_release_all+0xa8/0x110
>   really_probe+0x118/0x2d0
>   __driver_probe_device+0xc8/0xe0
>   driver_probe_device+0x54/0xec
>   __driver_attach+0xe0/0xf0
>   bus_for_each_dev+0x7c/0xc8
>   driver_attach+0x30/0x3c
>   bus_add_driver+0x17c/0x1c4
>   driver_register+0xc0/0xf8
>   __platform_driver_register+0x34/0x40
>   ...
> 
> This issue is introduced by commit d0243bbd5dd3 ("drivers core:
> Free dma_range_map when driver probe failed"). It frees
> dma_range_map before the call to devres_release_all, which is too
> early. The solution is to free dma_range_map only after
> devres_release_all.
> 
> Fixes: d0243bbd5dd3 ("drivers core: Free dma_range_map when driver probe
> failed")
> Signed-off-by: Filip Schauer <filip@xxxxxx>
> ---
>  drivers/base/dd.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index daeb9b5763ae..437cd61343b2 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -653,8 +653,6 @@ static int really_probe(struct device *dev, struct
> device_driver *drv)
>  	else if (drv->remove)
>  		drv->remove(dev);
>  probe_failed:
> - kfree(dev->dma_range_map);
> - dev->dma_range_map = NULL;
>  	if (dev->bus)
>  		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
>  					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
> @@ -662,6 +660,8 @@ static int really_probe(struct device *dev, struct
> device_driver *drv)
>  	device_links_no_driver(dev);
>  	devres_release_all(dev);
>  	arch_teardown_dma_ops(dev);
> + kfree(dev->dma_range_map);
> + dev->dma_range_map = NULL;
>  	driver_sysfs_remove(dev);
>  	dev->driver = NULL;
>  	dev_set_drvdata(dev, NULL);
> -- 
> 2.25.1
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
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