[PATCH v3 0/3] Fix NULL pointer dereference in RZ/{G2L,V2M,A2} pinctrl driver

[PATCH v3 0/3] Fix NULL pointer dereference in RZ/{G2L,V2M,A2} pinctrl driver

[Biju Das]

Fix NULL pointer dereference in RZ/{G2L,V2M,A2M} pinctrl driver due to
a race condition during boot. We have seen issues with RZ/{G2L,V2M} boards.
Based on the code, RZ/A2 will also hit this issue. So fixing RZ/A2 aswell.

This issue is reproducible with 1/200 reboots.

v2->v3:
 * Added comments for bitmap_lock and lock.
 * Moved map allocation down to reduce lock section.
 * Added locks for maps and pinctrl group and function creation/remove
   calls
 * Added unlock_and_done label for lock error path.
v1->v2:
 * Updated crash logs as per submitting patches doc.

Biju Das (3):
  pinctrl: renesas: rzg2l: Fix NULL pointer dereference in
    rzg2l_dt_subnode_to_map()
  pinctrl: renesas: rzv2m: Fix NULL pointer dereference in
    rzv2m_dt_subnode_to_map()
  pinctrl: renesas: rza2: Add lock around
    pinctrl_generic{{add,remove}_group,{add,remove}_function}

 drivers/pinctrl/renesas/pinctrl-rza2.c  | 15 ++++++-
 drivers/pinctrl/renesas/pinctrl-rzg2l.c | 58 ++++++++++++++-----------
 drivers/pinctrl/renesas/pinctrl-rzv2m.c | 56 ++++++++++++++----------
 3 files changed, 78 insertions(+), 51 deletions(-)

-- 
2.25.1

[PATCH v3 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Biju Das]

Fix the below random NULL pointer crash during boot by serializing
pinctrl group and function creation/remove calls in
rzg2l_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
 rzg2l_dt_subnode_to_map+0x314/0x44c
 rzg2l_dt_node_to_map+0x164/0x194
 pinctrl_dt_to_map+0x218/0x37c
 create_pinctrl+0x70/0x3d8

While at it, add comments for bitmap_lock and lock.

Fixes: c4c4637eb57f ("pinctrl: renesas: Add RZ/G2L pin and gpio controller driver")
Cc: stable@kernel.org
Tested-by: Chris Paterson <Chris.Paterson2@renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * Added comment for bitmap_lock and lock.
 * Moved map allocation down to reduce lock section.
 * Added locks for maps and pinctrl group and function creation/remove
   calls
 * Added unlock_and_done label for lock error path.
v1->v2:
 * Updated crash logs as per submitting patches doc.
---
 drivers/pinctrl/renesas/pinctrl-rzg2l.c | 58 ++++++++++++++-----------
 1 file changed, 33 insertions(+), 25 deletions(-)

diff --git a/drivers/pinctrl/renesas/pinctrl-rzg2l.c b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
index 4f34f8f24bde..571a32d2f697 100644
--- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
+++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
@@ -11,6 +11,7 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
@@ -149,10 +150,11 @@ struct rzg2l_pinctrl {
 	struct gpio_chip		gpio_chip;
 	struct pinctrl_gpio_range	gpio_range;
 	DECLARE_BITMAP(tint_slot, RZG2L_TINT_MAX_INTERRUPT);
-	spinlock_t			bitmap_lock;
+	spinlock_t			bitmap_lock; /* protect tint_slot bitmap */
 	unsigned int			hwirq[RZG2L_TINT_MAX_INTERRUPT];
 
-	spinlock_t			lock;
+	spinlock_t			lock; /* lock read/write registers */
+	struct mutex			mutex; /* serialize adding groups and functions */
 };
 
 static const unsigned int iolh_groupa_mA[] = { 2, 4, 8, 12 };
@@ -309,28 +311,6 @@ static int rzg2l_dt_subnode_to_map(struct pinctrl_dev *pctldev,
 	if (num_pins)
 		nmaps += num_pins;
 
-	maps = krealloc_array(maps, nmaps, sizeof(*maps), GFP_KERNEL);
-	if (!maps) {
-		ret = -ENOMEM;
-		goto done;
-	}
-
-	*map = maps;
-	*num_maps = nmaps;
-	if (num_pins) {
-		of_property_for_each_string(np, "pins", prop, pin) {
-			ret = rzg2l_map_add_config(&maps[idx], pin,
-						   PIN_MAP_TYPE_CONFIGS_PIN,
-						   configs, num_configs);
-			if (ret < 0)
-				goto done;
-
-			idx++;
-		}
-		ret = 0;
-		goto done;
-	}
-
 	pins = devm_kcalloc(pctrl->dev, num_pinmux, sizeof(*pins), GFP_KERNEL);
 	psel_val = devm_kcalloc(pctrl->dev, num_pinmux, sizeof(*psel_val),
 				GFP_KERNEL);
@@ -362,11 +342,34 @@ static int rzg2l_dt_subnode_to_map(struct pinctrl_dev *pctldev,
 		name = np->name;
 	}
 
+	mutex_lock(&pctrl->mutex);
+	maps = krealloc_array(maps, nmaps, sizeof(*maps), GFP_KERNEL);
+	if (!maps) {
+		ret = -ENOMEM;
+		goto unlock_and_done;
+	}
+
+	*map = maps;
+	*num_maps = nmaps;
+	if (num_pins) {
+		of_property_for_each_string(np, "pins", prop, pin) {
+			ret = rzg2l_map_add_config(&maps[idx], pin,
+						   PIN_MAP_TYPE_CONFIGS_PIN,
+						   configs, num_configs);
+			if (ret < 0)
+				goto unlock_and_done;
+
+			idx++;
+		}
+		ret = 0;
+		goto unlock_and_done;
+	}
+
 	/* 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;
-		goto done;
+		goto unlock_and_done;
 	}
 
 	/*
@@ -380,6 +383,8 @@ static int rzg2l_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;
@@ -391,6 +396,8 @@ static int rzg2l_dt_subnode_to_map(struct pinctrl_dev *pctldev,
 
 remove_group:
 	pinctrl_generic_remove_group(pctldev, gsel);
+unlock_and_done:
+	mutex_unlock(&pctrl->mutex);
 done:
 	*index = idx;
 	kfree(configs);
@@ -1503,6 +1510,7 @@ static int rzg2l_pinctrl_probe(struct platform_device *pdev)
 
 	spin_lock_init(&pctrl->lock);
 	spin_lock_init(&pctrl->bitmap_lock);
+	mutex_init(&pctrl->mutex);
 
 	platform_set_drvdata(pdev, pctrl);
 
-- 
2.25.1

Re: [PATCH v3 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Geert Uytterhoeven]

Hi Biju,

On Tue, Aug 15, 2023 at 3:16 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> Fix the below random NULL pointer crash during boot by serializing
> pinctrl group and function creation/remove calls in
> rzg2l_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
>  rzg2l_dt_subnode_to_map+0x314/0x44c
>  rzg2l_dt_node_to_map+0x164/0x194
>  pinctrl_dt_to_map+0x218/0x37c
>  create_pinctrl+0x70/0x3d8
>
> While at it, add comments for bitmap_lock and lock.
>
> Fixes: c4c4637eb57f ("pinctrl: renesas: Add RZ/G2L pin and gpio controller driver")
> Cc: stable@kernel.org
> Tested-by: Chris Paterson <Chris.Paterson2@renesas.com>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v2->v3:
>  * Added comment for bitmap_lock and lock.
>  * Moved map allocation down to reduce lock section.
>  * Added locks for maps and pinctrl group and function creation/remove
>    calls
>  * Added unlock_and_done label for lock error path.

Thanks for the update!

Upon closer look, I noticed that I had missed that the map allocation
is not global, but local to a specific DT node, so it does not
need protection by a lock.  If no one objects, I will back out that
change myself, queue this patch in renesas-pinctrl-for-v6.6, and send
a PR tomorrow.

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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

Re: [PATCH v3 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Geert Uytterhoeven]

On Thu, Aug 17, 2023 at 2:44 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Tue, Aug 15, 2023 at 3:16 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > Fix the below random NULL pointer crash during boot by serializing
> > pinctrl group and function creation/remove calls in
> > rzg2l_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
> >  rzg2l_dt_subnode_to_map+0x314/0x44c
> >  rzg2l_dt_node_to_map+0x164/0x194
> >  pinctrl_dt_to_map+0x218/0x37c
> >  create_pinctrl+0x70/0x3d8
> >
> > While at it, add comments for bitmap_lock and lock.
> >
> > Fixes: c4c4637eb57f ("pinctrl: renesas: Add RZ/G2L pin and gpio controller driver")
> > Cc: stable@kernel.org
> > Tested-by: Chris Paterson <Chris.Paterson2@renesas.com>
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > ---
> > v2->v3:
> >  * Added comment for bitmap_lock and lock.
> >  * Moved map allocation down to reduce lock section.
> >  * Added locks for maps and pinctrl group and function creation/remove
> >    calls
> >  * Added unlock_and_done label for lock error path.
>
> Thanks for the update!
>
> Upon closer look, I noticed that I had missed that the map allocation
> is not global, but local to a specific DT node, so it does not
> need protection by a lock.  If no one objects, I will back out that
> change myself, queue this patch in renesas-pinctrl-for-v6.6, and send
> a PR tomorrow.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Gr{oetje,eeting}s,


                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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

Re: [PATCH v3 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Linus Walleij]

On Thu, Aug 17, 2023 at 2:44 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> need protection by a lock.  If no one objects, I will back out that
> change myself, queue this patch in renesas-pinctrl-for-v6.6, and send
> a PR tomorrow.

Shouldn't this even go in for v6.5?
Or is it non-urgent?

(Maybe I already asked, I have teflon-memory.)

Yours,
Linus Walleij

Re: [PATCH v3 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Geert Uytterhoeven]

Hi Linus,

On Thu, Aug 17, 2023 at 3:38 PM Linus Walleij <linus.walleij@linaro.org> wrote:
> On Thu, Aug 17, 2023 at 2:44 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > need protection by a lock.  If no one objects, I will back out that
> > change myself, queue this patch in renesas-pinctrl-for-v6.6, and send
> > a PR tomorrow.
>
> Shouldn't this even go in for v6.5?
> Or is it non-urgent?
>
> (Maybe I already asked, I have teflon-memory.)

If you're still taking fixes for v6.5, I can do that.
Else, it will have to wait for a stable backport after v6.6-rc1.

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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

Re: [PATCH v3 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Geert Uytterhoeven]

Hi Linus,

On Thu, Aug 17, 2023 at 3:54 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Thu, Aug 17, 2023 at 3:38 PM Linus Walleij <linus.walleij@linaro.org> wrote:
> > On Thu, Aug 17, 2023 at 2:44 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > need protection by a lock.  If no one objects, I will back out that
> > > change myself, queue this patch in renesas-pinctrl-for-v6.6, and send
> > > a PR tomorrow.
> >
> > Shouldn't this even go in for v6.5?
> > Or is it non-urgent?
> >
> > (Maybe I already asked, I have teflon-memory.)
>
> If you're still taking fixes for v6.5, I can do that.
> Else, it will have to wait for a stable backport after v6.6-rc1.

IOW, please let me know if I should move these 3 commits to a fixes
branch. BTW, they conflict with commit 060f03e95454a0f4 ("pinctrl:
Explicitly include correct DT includes") in pinctrl/for-next...

https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git/log/?h=renesas-pinctrl

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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

Re: [PATCH v3 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Linus Walleij]

On Thu, Aug 17, 2023 at 5:57 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Thu, Aug 17, 2023 at 3:54 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Thu, Aug 17, 2023 at 3:38 PM Linus Walleij <linus.walleij@linaro.org> wrote:
> > > On Thu, Aug 17, 2023 at 2:44 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > > need protection by a lock.  If no one objects, I will back out that
> > > > change myself, queue this patch in renesas-pinctrl-for-v6.6, and send
> > > > a PR tomorrow.
> > >
> > > Shouldn't this even go in for v6.5?
> > > Or is it non-urgent?
> > >
> > > (Maybe I already asked, I have teflon-memory.)
> >
> > If you're still taking fixes for v6.5, I can do that.
> > Else, it will have to wait for a stable backport after v6.6-rc1.
>
> IOW, please let me know if I should move these 3 commits to a fixes
> branch.

I'd say that is up to the driver maintainer, hehe :D

I can only determine if changes to the core or my own drivers
are urgent. I am hopefully sending some fixes today but if more
urgent stuff need to go in, such is life.

> BTW, they conflict with commit 060f03e95454a0f4 ("pinctrl:
> Explicitly include correct DT includes") in pinctrl/for-next...

Yeah, we'll figure it out... I think. Worst case we toss some
merge conflicts at Torvalds.

Yours,
Linus Walleij

[PATCH v3 2/3] pinctrl: renesas: rzv2m: Fix NULL pointer dereference in rzv2m_dt_subnode_to_map()

[Biju Das]

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

While at it, add comment for lock.

Fixes: 92a9b8252576 ("pinctrl: renesas: Add RZ/V2M pin and gpio controller driver")
Cc: stable@kernel.org
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * Added comment for lock.
 * Moved map allocation down to reduce lock section.
 * Added locks for maps and pinctrl group and function creation/remove
   calls
 * Added unlock_and_done label for lock error path.
v1->v2:
 * Updated crash logs as per submitting patches doc.
---
 drivers/pinctrl/renesas/pinctrl-rzv2m.c | 56 ++++++++++++++-----------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/drivers/pinctrl/renesas/pinctrl-rzv2m.c b/drivers/pinctrl/renesas/pinctrl-rzv2m.c
index c73784b8b4ba..19586a0861a4 100644
--- 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>
@@ -123,7 +124,8 @@ struct rzv2m_pinctrl {
 	struct gpio_chip		gpio_chip;
 	struct pinctrl_gpio_range	gpio_range;
 
-	spinlock_t			lock;
+	spinlock_t			lock; /* lock read/write registers */
+	struct mutex			mutex; /* serialize adding groups and functions */
 };
 
 static const unsigned int drv_1_8V_group2_uA[] = { 1800, 3800, 7800, 11000 };
@@ -269,28 +271,6 @@ static int rzv2m_dt_subnode_to_map(struct pinctrl_dev *pctldev,
 	if (num_pins)
 		nmaps += num_pins;
 
-	maps = krealloc_array(maps, nmaps, sizeof(*maps), GFP_KERNEL);
-	if (!maps) {
-		ret = -ENOMEM;
-		goto done;
-	}
-
-	*map = maps;
-	*num_maps = nmaps;
-	if (num_pins) {
-		of_property_for_each_string(np, "pins", prop, pin) {
-			ret = rzv2m_map_add_config(&maps[idx], pin,
-						   PIN_MAP_TYPE_CONFIGS_PIN,
-						   configs, num_configs);
-			if (ret < 0)
-				goto done;
-
-			idx++;
-		}
-		ret = 0;
-		goto done;
-	}
-
 	pins = devm_kcalloc(pctrl->dev, num_pinmux, sizeof(*pins), GFP_KERNEL);
 	psel_val = devm_kcalloc(pctrl->dev, num_pinmux, sizeof(*psel_val),
 				GFP_KERNEL);
@@ -322,11 +302,34 @@ static int rzv2m_dt_subnode_to_map(struct pinctrl_dev *pctldev,
 		name = np->name;
 	}
 
+	mutex_lock(&pctrl->mutex);
+	maps = krealloc_array(maps, nmaps, sizeof(*maps), GFP_KERNEL);
+	if (!maps) {
+		ret = -ENOMEM;
+		goto unlock_and_done;
+	}
+
+	*map = maps;
+	*num_maps = nmaps;
+	if (num_pins) {
+		of_property_for_each_string(np, "pins", prop, pin) {
+			ret = rzv2m_map_add_config(&maps[idx], pin,
+						   PIN_MAP_TYPE_CONFIGS_PIN,
+						   configs, num_configs);
+			if (ret < 0)
+				goto unlock_and_done;
+
+			idx++;
+		}
+		ret = 0;
+		goto unlock_and_done;
+	}
+
 	/* 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;
-		goto done;
+		goto unlock_and_done;
 	}
 
 	/*
@@ -340,6 +343,8 @@ 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 +356,8 @@ static int rzv2m_dt_subnode_to_map(struct pinctrl_dev *pctldev,
 
 remove_group:
 	pinctrl_generic_remove_group(pctldev, gsel);
+unlock_and_done:
+	mutex_unlock(&pctrl->mutex);
 done:
 	*index = idx;
 	kfree(configs);
@@ -1065,6 +1072,7 @@ static int rzv2m_pinctrl_probe(struct platform_device *pdev)
 				     "failed to enable GPIO clk\n");
 
 	spin_lock_init(&pctrl->lock);
+	mutex_init(&pctrl->mutex);
 
 	platform_set_drvdata(pdev, pctrl);
 
-- 
2.25.1

Re: [PATCH v3 2/3] pinctrl: renesas: rzv2m: Fix NULL pointer dereference in rzv2m_dt_subnode_to_map()

[Geert Uytterhoeven]

Hi Biju,

On Tue, Aug 15, 2023 at 3:16 PM Biju Das <biju.das.jz@bp.renesas.com> 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
>
> While at it, add comment for lock.
>
> Fixes: 92a9b8252576 ("pinctrl: renesas: Add RZ/V2M pin and gpio controller driver")
> Cc: stable@kernel.org
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v2->v3:
>  * Added comment for lock.
>  * Moved map allocation down to reduce lock section.
>  * Added locks for maps and pinctrl group and function creation/remove
>    calls
>  * Added unlock_and_done label for lock error path.

Thanks for the update!

Upon closer look, I noticed that I had missed that the map allocation
is not global, but local to a specific DT node, so it does not
need protection by a lock.  If no one objects, I will back out that
change myself, queue this patch in renesas-pinctrl-for-v6.6, and send
a PR tomorrow.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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

[PATCH v3 3/3] pinctrl: renesas: rza2: Add lock around pinctrl_generic{{add,remove}_group,{add,remove}_function}

[Biju Das]

The pinctrl group and function creation/remove calls expect
caller to take care of locking. Add lock around these functions.

Fixes: b59d0e782706 ("pinctrl: Add RZ/A2 pin and gpio controller")
Cc: stable@kernel.org
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * Added unlock_and_done label for lock error path.
v1->v2:
 * No change.
---
 drivers/pinctrl/renesas/pinctrl-rza2.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/renesas/pinctrl-rza2.c b/drivers/pinctrl/renesas/pinctrl-rza2.c
index 0b454a31c4bd..cf0f130a3720 100644
--- a/drivers/pinctrl/renesas/pinctrl-rza2.c
+++ b/drivers/pinctrl/renesas/pinctrl-rza2.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/pinctrl/pinmux.h>
 #include <linux/platform_device.h>
@@ -47,6 +48,7 @@ struct rza2_pinctrl_priv {
 	struct pinctrl_dev *pctl;
 	struct pinctrl_gpio_range gpio_range;
 	int npins;
+	struct mutex mutex; /* serialize adding groups and functions */
 };
 
 #define RZA2_PDR(port)		(0x0000 + (port) * 2)	/* Direction 16-bit */
@@ -359,10 +361,13 @@ static int rza2_dt_node_to_map(struct pinctrl_dev *pctldev,
 		psel_val[i] = MUX_FUNC(value);
 	}
 
+	mutex_lock(&priv->mutex);
 	/* Register a single pin group listing all the pins we read from DT */
 	gsel = pinctrl_generic_add_group(pctldev, np->name, pins, npins, NULL);
-	if (gsel < 0)
-		return gsel;
+	if (gsel < 0) {
+		ret = gsel;
+		goto unlock_and_done;
+	}
 
 	/*
 	 * Register a single group function where the 'data' is an array PSEL
@@ -390,6 +395,7 @@ static int rza2_dt_node_to_map(struct pinctrl_dev *pctldev,
 	(*map)->data.mux.group = np->name;
 	(*map)->data.mux.function = np->name;
 	*num_maps = 1;
+	mutex_unlock(&priv->mutex);
 
 	return 0;
 
@@ -399,6 +405,9 @@ static int rza2_dt_node_to_map(struct pinctrl_dev *pctldev,
 remove_group:
 	pinctrl_generic_remove_group(pctldev, gsel);
 
+unlock_and_done:
+	mutex_unlock(&priv->mutex);
+
 	dev_err(priv->dev, "Unable to parse DT node %s\n", np->name);
 
 	return ret;
@@ -474,6 +483,8 @@ static int rza2_pinctrl_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
+	mutex_init(&priv->mutex);
+
 	platform_set_drvdata(pdev, priv);
 
 	priv->npins = (int)(uintptr_t)of_device_get_match_data(&pdev->dev) *
-- 
2.25.1

Re: [PATCH v3 3/3] pinctrl: renesas: rza2: Add lock around pinctrl_generic{{add,remove}_group,{add,remove}_function}

[Geert Uytterhoeven]

On Tue, Aug 15, 2023 at 3:16 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> The pinctrl group and function creation/remove calls expect
> caller to take care of locking. Add lock around these functions.
>
> Fixes: b59d0e782706 ("pinctrl: Add RZ/A2 pin and gpio controller")
> Cc: stable@kernel.org
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v2->v3:
>  * Added unlock_and_done label for lock error path.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-pinctrl-for-v6.6.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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