Hi Biju,
On Tue, Aug 15, 2023 at 9:56 AM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> Fix the below random NULL pointer crash during boot by serializing
> groups and functions creation in rzv2m_dt_subnode_to_map() with
> mutex lock.
>
> Crash logs:
> pc : __pi_strcmp+0x20/0x140
> lr : pinmux_func_name_to_selector+0x68/0xa4
> Call trace:
> __pi_strcmp+0x20/0x140
> pinmux_generic_add_function+0x34/0xcc
> rzv2m_dt_subnode_to_map+0x2e4/0x418
> rzv2m_dt_node_to_map+0x15c/0x18c
> pinctrl_dt_to_map+0x218/0x37c
> create_pinctrl+0x70/0x3d8
>
> Fixes: 92a9b8252576 ("pinctrl: renesas: Add RZ/V2M pin and gpio controller driver")
> Cc: stable@xxxxxxxxxx
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
> v1->v2:
> * Updated crash logs as per submitting patches doc.
Thanks for your patch!
> --- a/drivers/pinctrl/renesas/pinctrl-rzv2m.c
> +++ b/drivers/pinctrl/renesas/pinctrl-rzv2m.c
> @@ -14,6 +14,7 @@
> #include <linux/gpio/driver.h>
> #include <linux/io.h>
> #include <linux/module.h>
> +#include <linux/mutex.h>
> #include <linux/of.h>
> #include <linux/platform_device.h>
> #include <linux/spinlock.h>
> @@ -124,6 +125,7 @@ struct rzv2m_pinctrl {
> struct pinctrl_gpio_range gpio_range;
>
> spinlock_t lock;
> + struct mutex mutex; /* serialize adding groups and functions */
I guess it's not too late to add a comment to the other lock?
> };
>
> static const unsigned int drv_1_8V_group2_uA[] = { 1800, 3800, 7800, 11000 };
> @@ -322,10 +324,12 @@ static int rzv2m_dt_subnode_to_map(struct pinctrl_dev *pctldev,
> name = np->name;
> }
>
> + mutex_lock(&pctrl->mutex);
I think this is too late, as krealloc_array() above has already released
the old map.
> /* Register a single pin group listing all the pins we read from DT */
> gsel = pinctrl_generic_add_group(pctldev, name, pins, num_pinmux, NULL);
> if (gsel < 0) {
> ret = gsel;
> + mutex_unlock(&pctrl->mutex);
Please add a new label below, to avoid adding a call to mutex_unlock()
here.
> goto done;
> }
>
> @@ -340,6 +344,8 @@ static int rzv2m_dt_subnode_to_map(struct pinctrl_dev *pctldev,
> goto remove_group;
> }
>
> + mutex_unlock(&pctrl->mutex);
> +
> maps[idx].type = PIN_MAP_TYPE_MUX_GROUP;
> maps[idx].data.mux.group = name;
> maps[idx].data.mux.function = name;
> @@ -351,6 +357,7 @@ static int rzv2m_dt_subnode_to_map(struct pinctrl_dev *pctldev,
>
> remove_group:
> pinctrl_generic_remove_group(pctldev, gsel);
^^ new label here.
> + mutex_unlock(&pctrl->mutex);
> done:
> *index = idx;
> kfree(configs);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
