* [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction()
@ 2026-06-02 11:30 Christophe Leroy (CS GROUP)
2026-06-02 16:13 ` Bartosz Golaszewski
0 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy (CS GROUP) @ 2026-06-02 11:30 UTC (permalink / raw)
To: PRAT Maximilien, Linus Walleij, Dmitry Torokhov, Bartosz Golaszewski
Cc: Christophe Leroy (CS GROUP), linux-gpio, linux-kernel
Since kernel v6.15 the following big fat warning is encountered when
reading /sys/kernel/debug/gpio, leading to kernel latency while
emiting the warning, and panicing on systems configured to panic on
warnings.
------------[ cut here ]------------
WARNING: drivers/gpio/gpiolib.c:423 at gpiochip_get_direction+0x3c/0x48, CPU#0: cat/12531
CPU: 0 UID: 0 PID: 12531 Comm: cat Tainted: G W 7.0.10-gitc72c39~-01802-g28c351659258 #27 PREEMPT
Tainted: [W]=WARN
Hardware name: MIAE 8xx 0x500000 CMPC885
NIP: c043c2f8 LR: c043d740 CTR: 00000000
REGS: ca89bc20 TRAP: 0700 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24004884 XER: 00000302
GPR00: c043f3f0 ca89bce0 c3278000 c20b5f20 0000000d 00000002 00000000 c0a76208
GPR08: 00000001 00000000 cccccccd c313d830 84004884 100d815e c0a76208 c0a761f8
GPR16: c0a761f4 c0a76278 1048834c 10488350 c21c0b04 c21c0d93 c0a5fb74 c313d848
GPR24: c20b5f20 c21c0d94 00000000 00000000 c21c0d94 00000000 c21c0c00 c21c0b04
NIP [c043c2f8] gpiochip_get_direction+0x3c/0x48
LR [c043d740] gpiod_get_direction+0xa0/0x170
Call Trace:
[ca89bce0] [c28157e8] 0xc28157e8 (unreliable)
[ca89bd10] [c043f3f0] gpiolib_seq_show+0x370/0x524
[ca89bd90] [c021dd1c] seq_read_iter+0x174/0x618
[ca89bdd0] [c021e260] seq_read+0xa0/0xd0
[ca89be40] [c031063c] full_proxy_read+0x80/0xc4
[ca89be70] [c01df3e0] vfs_read+0xb4/0x35c
[ca89bee0] [c01e0180] ksys_read+0x8c/0x15c
[ca89bf10] [c000dc94] system_call_exception+0x88/0x154
[ca89bf30] [c00110a8] ret_from_syscall+0x0/0x28
---- interrupt: c00 at 0xfc629e8
NIP: 0fc629e8 LR: 0fc62a34 CTR: 00000000
REGS: ca89bf40 TRAP: 0c00 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 28004884 XER: 00000302
GPR00: 00000003 7f8df6a0 77e37540 00000003 7f8df6e8 00001000 00000000 00000000
GPR08: 00000000 7f8e3efc 00000000 7f8e06f0 7f8e3efc 100d815e 7fe70e10 100d0000
GPR16: 100d0000 00000001 1048834c 10488350 22000882 77e3fe68 1000596c 77e40b28
GPR24: 00000000 28004884 01000000 00001000 7f8df6e8 00000003 0fde36a0 00000000
NIP [0fc629e8] 0xfc629e8
LR [0fc62a34] 0xfc62a34
---- interrupt: c00
Code: 9421fff0 7c0802a6 90010014 7d2903a6 4e800421 2c030001 40810008 3860ffcc 80010014 38210010 7c0803a6 4e800020 <0fe00000> 3860ffa1 4e800020 81230020
---[ end trace 0000000000000000 ]---
This is due to a WARN_ON() added by commit ec2cceadfae7 ("gpiolib:
normalize the return value of gc->get() on behalf of buggy drivers")
when the gpiochip doesn't implement get_direction() function. But
according to the documentation in <linux/gpio/driver.h> implementing
get_direction() is only a recommendation, not a requirement. And
regarless, WARN_ON() has no added value here, dumping all CPU
registers doesn't give any useful information for that case.
Lower it to a simple warn_on_once() message.
Fixes: ec2cceadfae7 ("gpiolib: normalize the return value of gc->get() on behalf of buggy drivers")
Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
---
drivers/gpio/gpiolib.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 1e6dce430dca..6c0a5db443cb 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -426,8 +426,10 @@ static int gpiochip_get_direction(struct gpio_chip *gc, unsigned int offset)
lockdep_assert_held(&gc->gpiodev->srcu);
- if (WARN_ON(!gc->get_direction))
+ if (!gc->get_direction) {
+ pr_warn_once("%s: GPIO %s has no get_direction()\n", __func__, gc->label);
return -EOPNOTSUPP;
+ }
ret = gc->get_direction(gc, offset);
if (ret < 0)
--
2.54.0
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction()
2026-06-02 11:30 [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction() Christophe Leroy (CS GROUP)
@ 2026-06-02 16:13 ` Bartosz Golaszewski
2026-06-02 21:40 ` Christophe Leroy (CS GROUP)
0 siblings, 1 reply; 6+ messages in thread
From: Bartosz Golaszewski @ 2026-06-02 16:13 UTC (permalink / raw)
To: Christophe Leroy (CS GROUP)
Cc: PRAT Maximilien, Linus Walleij, Dmitry Torokhov,
Bartosz Golaszewski, linux-gpio, linux-kernel
On Tue, Jun 2, 2026 at 1:31 PM Christophe Leroy (CS GROUP)
<chleroy@kernel.org> wrote:
>
> Since kernel v6.15 the following big fat warning is encountered when
> reading /sys/kernel/debug/gpio, leading to kernel latency while
> emiting the warning, and panicing on systems configured to panic on
> warnings.
>
> ------------[ cut here ]------------
> WARNING: drivers/gpio/gpiolib.c:423 at gpiochip_get_direction+0x3c/0x48, CPU#0: cat/12531
> CPU: 0 UID: 0 PID: 12531 Comm: cat Tainted: G W 7.0.10-gitc72c39~-01802-g28c351659258 #27 PREEMPT
> Tainted: [W]=WARN
> Hardware name: MIAE 8xx 0x500000 CMPC885
> NIP: c043c2f8 LR: c043d740 CTR: 00000000
> REGS: ca89bc20 TRAP: 0700 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
> MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24004884 XER: 00000302
>
> GPR00: c043f3f0 ca89bce0 c3278000 c20b5f20 0000000d 00000002 00000000 c0a76208
> GPR08: 00000001 00000000 cccccccd c313d830 84004884 100d815e c0a76208 c0a761f8
> GPR16: c0a761f4 c0a76278 1048834c 10488350 c21c0b04 c21c0d93 c0a5fb74 c313d848
> GPR24: c20b5f20 c21c0d94 00000000 00000000 c21c0d94 00000000 c21c0c00 c21c0b04
> NIP [c043c2f8] gpiochip_get_direction+0x3c/0x48
> LR [c043d740] gpiod_get_direction+0xa0/0x170
> Call Trace:
> [ca89bce0] [c28157e8] 0xc28157e8 (unreliable)
> [ca89bd10] [c043f3f0] gpiolib_seq_show+0x370/0x524
> [ca89bd90] [c021dd1c] seq_read_iter+0x174/0x618
> [ca89bdd0] [c021e260] seq_read+0xa0/0xd0
> [ca89be40] [c031063c] full_proxy_read+0x80/0xc4
> [ca89be70] [c01df3e0] vfs_read+0xb4/0x35c
> [ca89bee0] [c01e0180] ksys_read+0x8c/0x15c
> [ca89bf10] [c000dc94] system_call_exception+0x88/0x154
> [ca89bf30] [c00110a8] ret_from_syscall+0x0/0x28
> ---- interrupt: c00 at 0xfc629e8
> NIP: 0fc629e8 LR: 0fc62a34 CTR: 00000000
> REGS: ca89bf40 TRAP: 0c00 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
> MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 28004884 XER: 00000302
>
> GPR00: 00000003 7f8df6a0 77e37540 00000003 7f8df6e8 00001000 00000000 00000000
> GPR08: 00000000 7f8e3efc 00000000 7f8e06f0 7f8e3efc 100d815e 7fe70e10 100d0000
> GPR16: 100d0000 00000001 1048834c 10488350 22000882 77e3fe68 1000596c 77e40b28
> GPR24: 00000000 28004884 01000000 00001000 7f8df6e8 00000003 0fde36a0 00000000
> NIP [0fc629e8] 0xfc629e8
> LR [0fc62a34] 0xfc62a34
> ---- interrupt: c00
> Code: 9421fff0 7c0802a6 90010014 7d2903a6 4e800421 2c030001 40810008 3860ffcc 80010014 38210010 7c0803a6 4e800020 <0fe00000> 3860ffa1 4e800020 81230020
> ---[ end trace 0000000000000000 ]---
>
> This is due to a WARN_ON() added by commit ec2cceadfae7 ("gpiolib:
> normalize the return value of gc->get() on behalf of buggy drivers")
> when the gpiochip doesn't implement get_direction() function. But
> according to the documentation in <linux/gpio/driver.h> implementing
> get_direction() is only a recommendation, not a requirement. And
> regarless, WARN_ON() has no added value here, dumping all CPU
> registers doesn't give any useful information for that case.
>
> Lower it to a simple warn_on_once() message.
>
> Fixes: ec2cceadfae7 ("gpiolib: normalize the return value of gc->get() on behalf of buggy drivers")
> Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
> ---
Please use scripts/get_maintainers.pl.
What driver are you using?
Bart
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction()
2026-06-02 16:13 ` Bartosz Golaszewski
@ 2026-06-02 21:40 ` Christophe Leroy (CS GROUP)
2026-06-03 8:11 ` Bartosz Golaszewski
0 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy (CS GROUP) @ 2026-06-02 21:40 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: PRAT Maximilien, Linus Walleij, Dmitry Torokhov,
Bartosz Golaszewski, linux-gpio, linux-kernel
Le 02/06/2026 à 18:13, Bartosz Golaszewski a écrit :
> On Tue, Jun 2, 2026 at 1:31 PM Christophe Leroy (CS GROUP)
> <chleroy@kernel.org> wrote:
>>
>> Since kernel v6.15 the following big fat warning is encountered when
>> reading /sys/kernel/debug/gpio, leading to kernel latency while
>> emiting the warning, and panicing on systems configured to panic on
>> warnings.
>>
>> ------------[ cut here ]------------
>> WARNING: drivers/gpio/gpiolib.c:423 at gpiochip_get_direction+0x3c/0x48, CPU#0: cat/12531
>> CPU: 0 UID: 0 PID: 12531 Comm: cat Tainted: G W 7.0.10-gitc72c39~-01802-g28c351659258 #27 PREEMPT
>> Tainted: [W]=WARN
>> Hardware name: MIAE 8xx 0x500000 CMPC885
>> NIP: c043c2f8 LR: c043d740 CTR: 00000000
>> REGS: ca89bc20 TRAP: 0700 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>> MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24004884 XER: 00000302
>>
>> GPR00: c043f3f0 ca89bce0 c3278000 c20b5f20 0000000d 00000002 00000000 c0a76208
>> GPR08: 00000001 00000000 cccccccd c313d830 84004884 100d815e c0a76208 c0a761f8
>> GPR16: c0a761f4 c0a76278 1048834c 10488350 c21c0b04 c21c0d93 c0a5fb74 c313d848
>> GPR24: c20b5f20 c21c0d94 00000000 00000000 c21c0d94 00000000 c21c0c00 c21c0b04
>> NIP [c043c2f8] gpiochip_get_direction+0x3c/0x48
>> LR [c043d740] gpiod_get_direction+0xa0/0x170
>> Call Trace:
>> [ca89bce0] [c28157e8] 0xc28157e8 (unreliable)
>> [ca89bd10] [c043f3f0] gpiolib_seq_show+0x370/0x524
>> [ca89bd90] [c021dd1c] seq_read_iter+0x174/0x618
>> [ca89bdd0] [c021e260] seq_read+0xa0/0xd0
>> [ca89be40] [c031063c] full_proxy_read+0x80/0xc4
>> [ca89be70] [c01df3e0] vfs_read+0xb4/0x35c
>> [ca89bee0] [c01e0180] ksys_read+0x8c/0x15c
>> [ca89bf10] [c000dc94] system_call_exception+0x88/0x154
>> [ca89bf30] [c00110a8] ret_from_syscall+0x0/0x28
>> ---- interrupt: c00 at 0xfc629e8
>> NIP: 0fc629e8 LR: 0fc62a34 CTR: 00000000
>> REGS: ca89bf40 TRAP: 0c00 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>> MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 28004884 XER: 00000302
>>
>> GPR00: 00000003 7f8df6a0 77e37540 00000003 7f8df6e8 00001000 00000000 00000000
>> GPR08: 00000000 7f8e3efc 00000000 7f8e06f0 7f8e3efc 100d815e 7fe70e10 100d0000
>> GPR16: 100d0000 00000001 1048834c 10488350 22000882 77e3fe68 1000596c 77e40b28
>> GPR24: 00000000 28004884 01000000 00001000 7f8df6e8 00000003 0fde36a0 00000000
>> NIP [0fc629e8] 0xfc629e8
>> LR [0fc62a34] 0xfc62a34
>> ---- interrupt: c00
>> Code: 9421fff0 7c0802a6 90010014 7d2903a6 4e800421 2c030001 40810008 3860ffcc 80010014 38210010 7c0803a6 4e800020 <0fe00000> 3860ffa1 4e800020 81230020
>> ---[ end trace 0000000000000000 ]---
>>
>> This is due to a WARN_ON() added by commit ec2cceadfae7 ("gpiolib:
>> normalize the return value of gc->get() on behalf of buggy drivers")
>> when the gpiochip doesn't implement get_direction() function. But
>> according to the documentation in <linux/gpio/driver.h> implementing
>> get_direction() is only a recommendation, not a requirement. And
>> regarless, WARN_ON() has no added value here, dumping all CPU
>> registers doesn't give any useful information for that case.
>>
>> Lower it to a simple warn_on_once() message.
>>
>> Fixes: ec2cceadfae7 ("gpiolib: normalize the return value of gc->get() on behalf of buggy drivers")
>> Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
>> ---
>
> Please use scripts/get_maintainers.pl.
That's what I did, what is the problem ?
$ ./scripts/get_maintainer.pl --nom --nor --nomultiline --norolestats
--nogit --nogit-fallback
tmp/0001-gpiolib-Remove-big-fat-warning-in-gpiochip_get_direc.patch
Dmitry Torokhov <dmitry.torokhov@gmail.com>, Linus Walleij
<linusw@kernel.org>, Bartosz Golaszewski
<bartosz.golaszewski@oss.qualcomm.com>, linux-gpio@vger.kernel.org,
linux-kernel@vger.kernel.org
>
> What driver are you using?
I have the following ones declared in the device tree:
CPM1_PIO_A: gpio-controller@950 {
#gpio-cells = <2>;
compatible = "fsl,cpm1-pario-bank-a";
reg = <0x950 0x10>;
gpio-controller;
};
CPM1_PIO_B: gpio-controller@ab8 {
#gpio-cells = <2>;
compatible = "fsl,cpm1-pario-bank-b";
reg = <0xab8 0x10>;
gpio-controller;
};
CPM1_PIO_C: gpio-controller@960 {
#gpio-cells = <2>;
compatible = "fsl,cpm1-pario-bank-c";
reg = <0x960 0x10>;
interrupts = <1 2 6 9 10 11 14 15 23 24 26 31>;
fsl,cpm1-gpio-irq-mask = <0x0fff>;
interrupt-parent = <&CPM_PIC>;
gpio-controller;
};
CPM1_PIO_D: gpio-controller@970 {
#gpio-cells = <2>;
compatible = "fsl,cpm1-pario-bank-d";
reg = <0x970 0x10>;
gpio-controller;
};
codec_fav: peb2466@3 {
compatible = "infineon,peb2466";
reg = <3>;
clocks = <&clk_mclk>;
clock-names = "mclk";
spi-max-frequency = <1000000>;
spi-cs-high;
reset-gpios = <&rst 6 GPIO_ACTIVE_LOW>;
#sound-dai-cells = <0>;
sound-name-prefix = "C2";
#gpio-cells = <2>;
gpio-controller;
firmware-name = "mcr-peb2466-coeffs.bin";
};
codec_radio: peb2466@7 {
compatible = "infineon,peb2466";
reg = <7>;
clocks = <&clk_mclk>;
clock-names = "mclk";
spi-max-frequency = <1000000>;
spi-cs-high;
reset-gpios = <&rst 5 GPIO_ACTIVE_LOW>;
#sound-dai-cells = <0>;
sound-name-prefix = "C1";
#gpio-cells = <2>;
gpio-controller;
firmware-name = "mcr-peb2466-coeffs.bin";
};
Christophe
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction()
2026-06-02 21:40 ` Christophe Leroy (CS GROUP)
@ 2026-06-03 8:11 ` Bartosz Golaszewski
2026-06-03 8:23 ` Christophe Leroy (CS GROUP)
0 siblings, 1 reply; 6+ messages in thread
From: Bartosz Golaszewski @ 2026-06-03 8:11 UTC (permalink / raw)
To: Christophe Leroy (CS GROUP)
Cc: PRAT Maximilien, Linus Walleij, Dmitry Torokhov,
Bartosz Golaszewski, linux-gpio, linux-kernel,
Bartosz Golaszewski
On Tue, 2 Jun 2026 23:40:22 +0200, "Christophe Leroy (CS GROUP)"
<chleroy@kernel.org> said:
>
>
> Le 02/06/2026 à 18:13, Bartosz Golaszewski a écrit :
>> On Tue, Jun 2, 2026 at 1:31 PM Christophe Leroy (CS GROUP)
>> <chleroy@kernel.org> wrote:
>>>
>>> Since kernel v6.15 the following big fat warning is encountered when
>>> reading /sys/kernel/debug/gpio, leading to kernel latency while
>>> emiting the warning, and panicing on systems configured to panic on
>>> warnings.
>>>
>>> ------------[ cut here ]------------
>>> WARNING: drivers/gpio/gpiolib.c:423 at gpiochip_get_direction+0x3c/0x48, CPU#0: cat/12531
>>> CPU: 0 UID: 0 PID: 12531 Comm: cat Tainted: G W 7.0.10-gitc72c39~-01802-g28c351659258 #27 PREEMPT
>>> Tainted: [W]=WARN
>>> Hardware name: MIAE 8xx 0x500000 CMPC885
>>> NIP: c043c2f8 LR: c043d740 CTR: 00000000
>>> REGS: ca89bc20 TRAP: 0700 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>>> MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24004884 XER: 00000302
>>>
>>> GPR00: c043f3f0 ca89bce0 c3278000 c20b5f20 0000000d 00000002 00000000 c0a76208
>>> GPR08: 00000001 00000000 cccccccd c313d830 84004884 100d815e c0a76208 c0a761f8
>>> GPR16: c0a761f4 c0a76278 1048834c 10488350 c21c0b04 c21c0d93 c0a5fb74 c313d848
>>> GPR24: c20b5f20 c21c0d94 00000000 00000000 c21c0d94 00000000 c21c0c00 c21c0b04
>>> NIP [c043c2f8] gpiochip_get_direction+0x3c/0x48
>>> LR [c043d740] gpiod_get_direction+0xa0/0x170
>>> Call Trace:
>>> [ca89bce0] [c28157e8] 0xc28157e8 (unreliable)
>>> [ca89bd10] [c043f3f0] gpiolib_seq_show+0x370/0x524
>>> [ca89bd90] [c021dd1c] seq_read_iter+0x174/0x618
>>> [ca89bdd0] [c021e260] seq_read+0xa0/0xd0
>>> [ca89be40] [c031063c] full_proxy_read+0x80/0xc4
>>> [ca89be70] [c01df3e0] vfs_read+0xb4/0x35c
>>> [ca89bee0] [c01e0180] ksys_read+0x8c/0x15c
>>> [ca89bf10] [c000dc94] system_call_exception+0x88/0x154
>>> [ca89bf30] [c00110a8] ret_from_syscall+0x0/0x28
>>> ---- interrupt: c00 at 0xfc629e8
>>> NIP: 0fc629e8 LR: 0fc62a34 CTR: 00000000
>>> REGS: ca89bf40 TRAP: 0c00 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>>> MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 28004884 XER: 00000302
>>>
>>> GPR00: 00000003 7f8df6a0 77e37540 00000003 7f8df6e8 00001000 00000000 00000000
>>> GPR08: 00000000 7f8e3efc 00000000 7f8e06f0 7f8e3efc 100d815e 7fe70e10 100d0000
>>> GPR16: 100d0000 00000001 1048834c 10488350 22000882 77e3fe68 1000596c 77e40b28
>>> GPR24: 00000000 28004884 01000000 00001000 7f8df6e8 00000003 0fde36a0 00000000
>>> NIP [0fc629e8] 0xfc629e8
>>> LR [0fc62a34] 0xfc62a34
>>> ---- interrupt: c00
>>> Code: 9421fff0 7c0802a6 90010014 7d2903a6 4e800421 2c030001 40810008 3860ffcc 80010014 38210010 7c0803a6 4e800020 <0fe00000> 3860ffa1 4e800020 81230020
>>> ---[ end trace 0000000000000000 ]---
>>>
>>> This is due to a WARN_ON() added by commit ec2cceadfae7 ("gpiolib:
>>> normalize the return value of gc->get() on behalf of buggy drivers")
>>> when the gpiochip doesn't implement get_direction() function. But
>>> according to the documentation in <linux/gpio/driver.h> implementing
>>> get_direction() is only a recommendation, not a requirement. And
>>> regarless, WARN_ON() has no added value here, dumping all CPU
>>> registers doesn't give any useful information for that case.
>>>
>>> Lower it to a simple warn_on_once() message.
>>>
>>> Fixes: ec2cceadfae7 ("gpiolib: normalize the return value of gc->get() on behalf of buggy drivers")
>>> Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
>>> ---
>>
>> Please use scripts/get_maintainers.pl.
>
> That's what I did, what is the problem ?
>
> $ ./scripts/get_maintainer.pl --nom --nor --nomultiline --norolestats
> --nogit --nogit-fallback
> tmp/0001-gpiolib-Remove-big-fat-warning-in-gpiochip_get_direc.patch
> Dmitry Torokhov <dmitry.torokhov@gmail.com>, Linus Walleij
> <linusw@kernel.org>, Bartosz Golaszewski
> <bartosz.golaszewski@oss.qualcomm.com>, linux-gpio@vger.kernel.org,
> linux-kernel@vger.kernel.org
>
I would expect my brgl@kernel.org address to show up, the -nom option removes
it.
>>
>> What driver are you using?
>
> I have the following ones declared in the device tree:
>
> CPM1_PIO_A: gpio-controller@950 {
> #gpio-cells = <2>;
> compatible = "fsl,cpm1-pario-bank-a";
> reg = <0x950 0x10>;
> gpio-controller;
> };
I'll send a patch shortly implementing get_direction() for it.
Bart
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction()
2026-06-03 8:11 ` Bartosz Golaszewski
@ 2026-06-03 8:23 ` Christophe Leroy (CS GROUP)
2026-06-03 8:33 ` Bartosz Golaszewski
0 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy (CS GROUP) @ 2026-06-03 8:23 UTC (permalink / raw)
To: Bartosz Golaszewski
Cc: PRAT Maximilien, Linus Walleij, Dmitry Torokhov,
Bartosz Golaszewski, linux-gpio, linux-kernel
Le 03/06/2026 à 10:11, Bartosz Golaszewski a écrit :
> On Tue, 2 Jun 2026 23:40:22 +0200, "Christophe Leroy (CS GROUP)"
> <chleroy@kernel.org> said:
>>
>>
>> Le 02/06/2026 à 18:13, Bartosz Golaszewski a écrit :
>>> On Tue, Jun 2, 2026 at 1:31 PM Christophe Leroy (CS GROUP)
>>> <chleroy@kernel.org> wrote:
>>>>
>>>> Since kernel v6.15 the following big fat warning is encountered when
>>>> reading /sys/kernel/debug/gpio, leading to kernel latency while
>>>> emiting the warning, and panicing on systems configured to panic on
>>>> warnings.
>>>>
>>>> ------------[ cut here ]------------
>>>> WARNING: drivers/gpio/gpiolib.c:423 at gpiochip_get_direction+0x3c/0x48, CPU#0: cat/12531
>>>> CPU: 0 UID: 0 PID: 12531 Comm: cat Tainted: G W 7.0.10-gitc72c39~-01802-g28c351659258 #27 PREEMPT
>>>> Tainted: [W]=WARN
>>>> Hardware name: MIAE 8xx 0x500000 CMPC885
>>>> NIP: c043c2f8 LR: c043d740 CTR: 00000000
>>>> REGS: ca89bc20 TRAP: 0700 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>>>> MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24004884 XER: 00000302
>>>>
>>>> GPR00: c043f3f0 ca89bce0 c3278000 c20b5f20 0000000d 00000002 00000000 c0a76208
>>>> GPR08: 00000001 00000000 cccccccd c313d830 84004884 100d815e c0a76208 c0a761f8
>>>> GPR16: c0a761f4 c0a76278 1048834c 10488350 c21c0b04 c21c0d93 c0a5fb74 c313d848
>>>> GPR24: c20b5f20 c21c0d94 00000000 00000000 c21c0d94 00000000 c21c0c00 c21c0b04
>>>> NIP [c043c2f8] gpiochip_get_direction+0x3c/0x48
>>>> LR [c043d740] gpiod_get_direction+0xa0/0x170
>>>> Call Trace:
>>>> [ca89bce0] [c28157e8] 0xc28157e8 (unreliable)
>>>> [ca89bd10] [c043f3f0] gpiolib_seq_show+0x370/0x524
>>>> [ca89bd90] [c021dd1c] seq_read_iter+0x174/0x618
>>>> [ca89bdd0] [c021e260] seq_read+0xa0/0xd0
>>>> [ca89be40] [c031063c] full_proxy_read+0x80/0xc4
>>>> [ca89be70] [c01df3e0] vfs_read+0xb4/0x35c
>>>> [ca89bee0] [c01e0180] ksys_read+0x8c/0x15c
>>>> [ca89bf10] [c000dc94] system_call_exception+0x88/0x154
>>>> [ca89bf30] [c00110a8] ret_from_syscall+0x0/0x28
>>>> ---- interrupt: c00 at 0xfc629e8
>>>> NIP: 0fc629e8 LR: 0fc62a34 CTR: 00000000
>>>> REGS: ca89bf40 TRAP: 0c00 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>>>> MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 28004884 XER: 00000302
>>>>
>>>> GPR00: 00000003 7f8df6a0 77e37540 00000003 7f8df6e8 00001000 00000000 00000000
>>>> GPR08: 00000000 7f8e3efc 00000000 7f8e06f0 7f8e3efc 100d815e 7fe70e10 100d0000
>>>> GPR16: 100d0000 00000001 1048834c 10488350 22000882 77e3fe68 1000596c 77e40b28
>>>> GPR24: 00000000 28004884 01000000 00001000 7f8df6e8 00000003 0fde36a0 00000000
>>>> NIP [0fc629e8] 0xfc629e8
>>>> LR [0fc62a34] 0xfc62a34
>>>> ---- interrupt: c00
>>>> Code: 9421fff0 7c0802a6 90010014 7d2903a6 4e800421 2c030001 40810008 3860ffcc 80010014 38210010 7c0803a6 4e800020 <0fe00000> 3860ffa1 4e800020 81230020
>>>> ---[ end trace 0000000000000000 ]---
>>>>
>>>> This is due to a WARN_ON() added by commit ec2cceadfae7 ("gpiolib:
>>>> normalize the return value of gc->get() on behalf of buggy drivers")
>>>> when the gpiochip doesn't implement get_direction() function. But
>>>> according to the documentation in <linux/gpio/driver.h> implementing
>>>> get_direction() is only a recommendation, not a requirement. And
>>>> regarless, WARN_ON() has no added value here, dumping all CPU
>>>> registers doesn't give any useful information for that case.
>>>>
>>>> Lower it to a simple warn_on_once() message.
>>>>
>>>> Fixes: ec2cceadfae7 ("gpiolib: normalize the return value of gc->get() on behalf of buggy drivers")
>>>> Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
>>>> ---
>>>
>>> Please use scripts/get_maintainers.pl.
>>
>> That's what I did, what is the problem ?
>>
>> $ ./scripts/get_maintainer.pl --nom --nor --nomultiline --norolestats
>> --nogit --nogit-fallback
>> tmp/0001-gpiolib-Remove-big-fat-warning-in-gpiochip_get_direc.patch
>> Dmitry Torokhov <dmitry.torokhov@gmail.com>, Linus Walleij
>> <linusw@kernel.org>, Bartosz Golaszewski
>> <bartosz.golaszewski@oss.qualcomm.com>, linux-gpio@vger.kernel.org,
>> linux-kernel@vger.kernel.org
>>
>
> I would expect my brgl@kernel.org address to show up, the -nom option removes
> it.
Ah .. I see. Thanks for the notice.
Indeed I use two calls, first one to populate the To:
./scripts/get_maintainer.pl --nol --nomultiline --norolestats --nogit
--nogit-fallback
then second one to populate the Cc:
./scripts/get_maintainer.pl --nom --nor --nomultiline --norolestats
--nogit --nogit-fallback
Then I saw same names appearing in second result in addition to mailing
lists so I took only the second result, overlooking that your adress was
different between the two results.
Indeed the second result was initially supposed to only provide the
mailing lists, but since some time now it also provides names and I have
to manually compare the two results to avoid duplicates. I need to look
into that more deeply.
>
>>>
>>> What driver are you using?
>>
>> I have the following ones declared in the device tree:
>>
>> CPM1_PIO_A: gpio-controller@950 {
>> #gpio-cells = <2>;
>> compatible = "fsl,cpm1-pario-bank-a";
>> reg = <0x950 0x10>;
>> gpio-controller;
>> };
>
> I'll send a patch shortly implementing get_direction() for it.
Thanks
Christophe
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction()
2026-06-03 8:23 ` Christophe Leroy (CS GROUP)
@ 2026-06-03 8:33 ` Bartosz Golaszewski
0 siblings, 0 replies; 6+ messages in thread
From: Bartosz Golaszewski @ 2026-06-03 8:33 UTC (permalink / raw)
To: Christophe Leroy (CS GROUP)
Cc: PRAT Maximilien, Linus Walleij, Dmitry Torokhov,
Bartosz Golaszewski, linux-gpio, linux-kernel,
Bartosz Golaszewski
On Wed, 3 Jun 2026 10:23:08 +0200, "Christophe Leroy (CS GROUP)"
<chleroy@kernel.org> said:
>
>
> Le 03/06/2026 à 10:11, Bartosz Golaszewski a écrit :
>> On Tue, 2 Jun 2026 23:40:22 +0200, "Christophe Leroy (CS GROUP)"
>> <chleroy@kernel.org> said:
>>>
>>>
>>> Le 02/06/2026 à 18:13, Bartosz Golaszewski a écrit :
>>>> On Tue, Jun 2, 2026 at 1:31 PM Christophe Leroy (CS GROUP)
>>>> <chleroy@kernel.org> wrote:
>>>>>
>>>>> Since kernel v6.15 the following big fat warning is encountered when
>>>>> reading /sys/kernel/debug/gpio, leading to kernel latency while
>>>>> emiting the warning, and panicing on systems configured to panic on
>>>>> warnings.
>>>>>
>>>>> ------------[ cut here ]------------
>>>>> WARNING: drivers/gpio/gpiolib.c:423 at gpiochip_get_direction+0x3c/0x48, CPU#0: cat/12531
>>>>> CPU: 0 UID: 0 PID: 12531 Comm: cat Tainted: G W 7.0.10-gitc72c39~-01802-g28c351659258 #27 PREEMPT
>>>>> Tainted: [W]=WARN
>>>>> Hardware name: MIAE 8xx 0x500000 CMPC885
>>>>> NIP: c043c2f8 LR: c043d740 CTR: 00000000
>>>>> REGS: ca89bc20 TRAP: 0700 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>>>>> MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24004884 XER: 00000302
>>>>>
>>>>> GPR00: c043f3f0 ca89bce0 c3278000 c20b5f20 0000000d 00000002 00000000 c0a76208
>>>>> GPR08: 00000001 00000000 cccccccd c313d830 84004884 100d815e c0a76208 c0a761f8
>>>>> GPR16: c0a761f4 c0a76278 1048834c 10488350 c21c0b04 c21c0d93 c0a5fb74 c313d848
>>>>> GPR24: c20b5f20 c21c0d94 00000000 00000000 c21c0d94 00000000 c21c0c00 c21c0b04
>>>>> NIP [c043c2f8] gpiochip_get_direction+0x3c/0x48
>>>>> LR [c043d740] gpiod_get_direction+0xa0/0x170
>>>>> Call Trace:
>>>>> [ca89bce0] [c28157e8] 0xc28157e8 (unreliable)
>>>>> [ca89bd10] [c043f3f0] gpiolib_seq_show+0x370/0x524
>>>>> [ca89bd90] [c021dd1c] seq_read_iter+0x174/0x618
>>>>> [ca89bdd0] [c021e260] seq_read+0xa0/0xd0
>>>>> [ca89be40] [c031063c] full_proxy_read+0x80/0xc4
>>>>> [ca89be70] [c01df3e0] vfs_read+0xb4/0x35c
>>>>> [ca89bee0] [c01e0180] ksys_read+0x8c/0x15c
>>>>> [ca89bf10] [c000dc94] system_call_exception+0x88/0x154
>>>>> [ca89bf30] [c00110a8] ret_from_syscall+0x0/0x28
>>>>> ---- interrupt: c00 at 0xfc629e8
>>>>> NIP: 0fc629e8 LR: 0fc62a34 CTR: 00000000
>>>>> REGS: ca89bf40 TRAP: 0c00 Tainted: G W (7.0.10-gitc72c39~-01802-g28c351659258)
>>>>> MSR: 0000d032 <EE,PR,ME,IR,DR,RI> CR: 28004884 XER: 00000302
>>>>>
>>>>> GPR00: 00000003 7f8df6a0 77e37540 00000003 7f8df6e8 00001000 00000000 00000000
>>>>> GPR08: 00000000 7f8e3efc 00000000 7f8e06f0 7f8e3efc 100d815e 7fe70e10 100d0000
>>>>> GPR16: 100d0000 00000001 1048834c 10488350 22000882 77e3fe68 1000596c 77e40b28
>>>>> GPR24: 00000000 28004884 01000000 00001000 7f8df6e8 00000003 0fde36a0 00000000
>>>>> NIP [0fc629e8] 0xfc629e8
>>>>> LR [0fc62a34] 0xfc62a34
>>>>> ---- interrupt: c00
>>>>> Code: 9421fff0 7c0802a6 90010014 7d2903a6 4e800421 2c030001 40810008 3860ffcc 80010014 38210010 7c0803a6 4e800020 <0fe00000> 3860ffa1 4e800020 81230020
>>>>> ---[ end trace 0000000000000000 ]---
>>>>>
>>>>> This is due to a WARN_ON() added by commit ec2cceadfae7 ("gpiolib:
>>>>> normalize the return value of gc->get() on behalf of buggy drivers")
>>>>> when the gpiochip doesn't implement get_direction() function. But
>>>>> according to the documentation in <linux/gpio/driver.h> implementing
>>>>> get_direction() is only a recommendation, not a requirement. And
>>>>> regarless, WARN_ON() has no added value here, dumping all CPU
>>>>> registers doesn't give any useful information for that case.
>>>>>
>>>>> Lower it to a simple warn_on_once() message.
>>>>>
>>>>> Fixes: ec2cceadfae7 ("gpiolib: normalize the return value of gc->get() on behalf of buggy drivers")
>>>>> Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
>>>>> ---
>>>>
>>>> Please use scripts/get_maintainers.pl.
>>>
>>> That's what I did, what is the problem ?
>>>
>>> $ ./scripts/get_maintainer.pl --nom --nor --nomultiline --norolestats
>>> --nogit --nogit-fallback
>>> tmp/0001-gpiolib-Remove-big-fat-warning-in-gpiochip_get_direc.patch
>>> Dmitry Torokhov <dmitry.torokhov@gmail.com>, Linus Walleij
>>> <linusw@kernel.org>, Bartosz Golaszewski
>>> <bartosz.golaszewski@oss.qualcomm.com>, linux-gpio@vger.kernel.org,
>>> linux-kernel@vger.kernel.org
>>>
>>
>> I would expect my brgl@kernel.org address to show up, the -nom option removes
>> it.
>
> Ah .. I see. Thanks for the notice.
>
> Indeed I use two calls, first one to populate the To:
>
> ./scripts/get_maintainer.pl --nol --nomultiline --norolestats --nogit
> --nogit-fallback
>
> then second one to populate the Cc:
>
> ./scripts/get_maintainer.pl --nom --nor --nomultiline --norolestats
> --nogit --nogit-fallback
>
> Then I saw same names appearing in second result in addition to mailing
> lists so I took only the second result, overlooking that your adress was
> different between the two results.
>
> Indeed the second result was initially supposed to only provide the
> mailing lists, but since some time now it also provides names and I have
> to manually compare the two results to avoid duplicates. I need to look
> into that more deeply.
>
May I interest you in b4 - the de-facto standard tool for managing kernel
patches? :)
Bart
>
>>
>>>>
>>>> What driver are you using?
>>>
>>> I have the following ones declared in the device tree:
>>>
>>> CPM1_PIO_A: gpio-controller@950 {
>>> #gpio-cells = <2>;
>>> compatible = "fsl,cpm1-pario-bank-a";
>>> reg = <0x950 0x10>;
>>> gpio-controller;
>>> };
>>
>> I'll send a patch shortly implementing get_direction() for it.
>
> Thanks
>
> Christophe
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-06-03 8:33 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-06-02 11:30 [PATCH] gpiolib: Remove big fat warning in gpiochip_get_direction() Christophe Leroy (CS GROUP)
2026-06-02 16:13 ` Bartosz Golaszewski
2026-06-02 21:40 ` Christophe Leroy (CS GROUP)
2026-06-03 8:11 ` Bartosz Golaszewski
2026-06-03 8:23 ` Christophe Leroy (CS GROUP)
2026-06-03 8:33 ` Bartosz Golaszewski
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