RE: [PATCH 3/3] misc: microchip: pci1xxxx: Fix the error handling paths of gp_aux_bus_probe()

Kumaravel.Thiagarajan
2022-09-19T17:47:51Z

> -----Original Message-----
> From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Sent: Sunday, September 18, 2022 11:58 AM
> To: Kumaravel Thiagarajan - I21417
> <Kumaravel.Thiagarajan@microchip.com>; Arnd Bergmann
> <arnd@arndb.de>; Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-kernel@vger.kernel.org; kernel-janitors@vger.kernel.org;
> Christophe JAILLET <christophe.jaillet@wanadoo.fr>; linux-
> gpio@vger.kernel.org
> Subject: [PATCH 3/3] misc: microchip: pci1xxxx: Fix the error handling paths
> of gp_aux_bus_probe()
>
> There are several issues related to the error handling paths of
> gp_aux_bus_probe():
> - some resources may be released twice. Once explicitly in the error
> handling path, and once via the release() function
> - auxiliary_device_delete() should be called after the first successful
> auxiliary_device_add()
Thanks for your patch. I had noticed this after one of the reviewers had only partially fixed them
up. I need some time to review and test your patch with the hardware before approving them.

>
> To fix them, reorder the code:
> - move the place where we get the irq for the 2nd wrapper.
> - call kfree() and ida_free() after error checks, rather then in the
> error handling path.
> - have the error handling path look like the remove function
>
> Fixes: 393fc2f5948f ("misc: microchip: pci1xxxx: load auxiliary bus driver for
> the PIO function in the multi-function endpoint of pci1xxxx device.")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> This patch is speculative and untested, review with care.
>
> Other solutions are possible.
> For example, we could use devm_kzalloc() to simplify the error handling path
> and the release function.
I thought about this but had some doubts whether it will work with the auxiliary bus
architecture as the memory allocated will get tagged with the same device pointer.
I need to do some experiments before taking up this path.

Thank You.

Regards,
Kumar