arm64: libgpiod: refcount_t: underflow; use-after-free.

arm64: libgpiod: refcount_t: underflow; use-after-free.

[Naresh Kamboju]

Following kernel warning notices on qemu-arm64, qemu-arm and also on devices
running Linux version v6.2.0 while running libgpiod tests.

+ ./gpiod.sh /opt/libgpiod/bin/
  [INFO]    libgpiod test suite
  [INFO]    117 tests registered
  [INFO]    checking the linux kernel version
  [INFO]    kernel release is v6.2.0 - ok to run tests
  [INFO]    using gpio-tools from '/usr/bin'
[   10.499036] ------------[ cut here ]------------
[   10.499656] refcount_t: underflow; use-after-free.
[   10.500264] WARNING: CPU: 2 PID: 291 at lib/refcount.c:28
refcount_warn_saturate+0xf4/0x144
[   10.501306] Modules linked in: gpio_mockup(-) cfg80211 bluetooth
rfkill crct10dif_ce fuse drm
[   10.502364] CPU: 2 PID: 291 Comm: gpiod-test Not tainted 6.2.0 #1
[   10.503229] Hardware name: linux,dummy-virt (DT)
[   10.503883] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   10.505331] pc : refcount_warn_saturate+0xf4/0x144
[   10.505723] lr : refcount_warn_saturate+0xf4/0x144
[   10.506115] sp : ffff800008983cd0
[   10.506391] x29: ffff800008983cd0 x28: ffff0000c4c4c100 x27: 0000000000000000
[   10.506961] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
[   10.507533] x23: 0000000000000200 x22: ffff0000c4e66800 x21: ffff0000c7734640
[   10.508104] x20: 0000000000000001 x19: ffff0000c7734600 x18: ffffffffffffffff
[   10.508677] x17: 3d4d455453595342 x16: ffffcf0234432020 x15: ffff800088983957
[   10.509424] x14: 0000000000000000 x13: 2e656572662d7265 x12: 7466612d65737520
[   10.510003] x11: 3b776f6c66726564 x10: ffffcf02365db580 x9 : ffffcf0233b20138
[   10.510575] x8 : 00000000ffffefff x7 : ffffcf02365db580 x6 : 0000000000000001
[   10.511145] x5 : ffffcf023655f000 x4 : ffffcf023655f2e8 x3 : 0000000000000000
[   10.511721] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c4c4c100
[   10.512294] Call trace:
[   10.512494]  refcount_warn_saturate+0xf4/0x144
[   10.512971]  kobject_put+0x164/0x220
[   10.513224]  fwnode_remove_software_node+0x44/0x60
[   10.513554]  gpio_mockup_unregister_pdevs+0x54/0x70 [gpio_mockup]
[   10.513970]  gpio_mockup_exit+0x10/0x328 [gpio_mockup]
[   10.514322]  __arm64_sys_delete_module+0x190/0x2a0
[   10.514653]  invoke_syscall+0x50/0x120
[   10.514915]  el0_svc_common.constprop.0+0x104/0x124
[   10.515277]  do_el0_svc+0x44/0xcc
[   10.515541]  el0_svc+0x30/0x94
[   10.515788]  el0t_64_sync_handler+0xbc/0x13c
[   10.516126]  el0t_64_sync+0x190/0x194
[   10.516419] ---[ end trace 0000000000000000 ]---


Build and test logs,
https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/test/ctxless-get-value-single-line/log
https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/tests/


--
Linaro LKFT
https://lkft.linaro.org

Re: arm64: libgpiod: refcount_t: underflow; use-after-free.

[Andy Shevchenko]

On Mon, Feb 20, 2023 at 08:29:27PM +0530, Naresh Kamboju wrote:
> Following kernel warning notices on qemu-arm64, qemu-arm and also on devices
> running Linux version v6.2.0 while running libgpiod tests.
> 
> + ./gpiod.sh /opt/libgpiod/bin/
>   [INFO]    libgpiod test suite
>   [INFO]    117 tests registered
>   [INFO]    checking the linux kernel version
>   [INFO]    kernel release is v6.2.0 - ok to run tests
>   [INFO]    using gpio-tools from '/usr/bin'
> [   10.499036] ------------[ cut here ]------------
> [   10.499656] refcount_t: underflow; use-after-free.
> [   10.500264] WARNING: CPU: 2 PID: 291 at lib/refcount.c:28
> refcount_warn_saturate+0xf4/0x144
> [   10.501306] Modules linked in: gpio_mockup(-) cfg80211 bluetooth
> rfkill crct10dif_ce fuse drm
> [   10.502364] CPU: 2 PID: 291 Comm: gpiod-test Not tainted 6.2.0 #1
> [   10.503229] Hardware name: linux,dummy-virt (DT)
> [   10.503883] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [   10.505331] pc : refcount_warn_saturate+0xf4/0x144
> [   10.505723] lr : refcount_warn_saturate+0xf4/0x144
> [   10.506115] sp : ffff800008983cd0
> [   10.506391] x29: ffff800008983cd0 x28: ffff0000c4c4c100 x27: 0000000000000000
> [   10.506961] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
> [   10.507533] x23: 0000000000000200 x22: ffff0000c4e66800 x21: ffff0000c7734640
> [   10.508104] x20: 0000000000000001 x19: ffff0000c7734600 x18: ffffffffffffffff
> [   10.508677] x17: 3d4d455453595342 x16: ffffcf0234432020 x15: ffff800088983957
> [   10.509424] x14: 0000000000000000 x13: 2e656572662d7265 x12: 7466612d65737520
> [   10.510003] x11: 3b776f6c66726564 x10: ffffcf02365db580 x9 : ffffcf0233b20138
> [   10.510575] x8 : 00000000ffffefff x7 : ffffcf02365db580 x6 : 0000000000000001
> [   10.511145] x5 : ffffcf023655f000 x4 : ffffcf023655f2e8 x3 : 0000000000000000
> [   10.511721] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c4c4c100
> [   10.512294] Call trace:
> [   10.512494]  refcount_warn_saturate+0xf4/0x144
> [   10.512971]  kobject_put+0x164/0x220
> [   10.513224]  fwnode_remove_software_node+0x44/0x60
> [   10.513554]  gpio_mockup_unregister_pdevs+0x54/0x70 [gpio_mockup]
> [   10.513970]  gpio_mockup_exit+0x10/0x328 [gpio_mockup]
> [   10.514322]  __arm64_sys_delete_module+0x190/0x2a0
> [   10.514653]  invoke_syscall+0x50/0x120
> [   10.514915]  el0_svc_common.constprop.0+0x104/0x124
> [   10.515277]  do_el0_svc+0x44/0xcc
> [   10.515541]  el0_svc+0x30/0x94
> [   10.515788]  el0t_64_sync_handler+0xbc/0x13c
> [   10.516126]  el0t_64_sync+0x190/0x194
> [   10.516419] ---[ end trace 0000000000000000 ]---
> 
> 
> Build and test logs,
> https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/test/ctxless-get-value-single-line/log
> https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/tests/

Can you give a try of the patch below?

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 77510e4f47de..1807678f032b 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -557,7 +557,7 @@ static void platform_device_release(struct device *dev)
 	struct platform_object *pa = container_of(dev, struct platform_object,
 						  pdev.dev);
 
-	of_node_put(pa->pdev.dev.of_node);
+	fwnode_handle_put(dev_fwnode(&pa->pdev.dev));
 	kfree(pa->pdev.dev.platform_data);
 	kfree(pa->pdev.mfd_cell);
 	kfree(pa->pdev.resource);
@@ -814,8 +814,7 @@ struct platform_device *platform_device_register_full(
 		return ERR_PTR(-ENOMEM);
 
 	pdev->dev.parent = pdevinfo->parent;
-	pdev->dev.fwnode = pdevinfo->fwnode;
-	pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode));
+	device_set_node(&pdev->dev, fwnode_handle_get(pdevinfo->fwnode));
 	pdev->dev.of_node_reused = pdevinfo->of_node_reused;
 
 	if (pdevinfo->dma_mask) {
@@ -844,8 +843,8 @@ struct platform_device *platform_device_register_full(
 	ret = platform_device_add(pdev);
 	if (ret) {
 err:
-		ACPI_COMPANION_SET(&pdev->dev, NULL);
 		platform_device_put(pdev);
+		fwnode_handle_put(pdevinfo->fwnode);
 		return ERR_PTR(ret);
 	}
 
-- 
With Best Regards,
Andy Shevchenko

Re: arm64: libgpiod: refcount_t: underflow; use-after-free.

[Andy Shevchenko]

On Tue, Feb 21, 2023 at 07:13:31PM +0200, Andy Shevchenko wrote:
> On Mon, Feb 20, 2023 at 08:29:27PM +0530, Naresh Kamboju wrote:
> > Following kernel warning notices on qemu-arm64, qemu-arm and also on devices
> > running Linux version v6.2.0 while running libgpiod tests.

...

> -		ACPI_COMPANION_SET(&pdev->dev, NULL);

This line should stay otherwise it will remove the device that may share
the fwnode with this newly created platform device.

-- 
With Best Regards,
Andy Shevchenko

Re: arm64: libgpiod: refcount_t: underflow; use-after-free.

[Bartosz Golaszewski]

On Mon, Feb 20, 2023 at 3:59 PM Naresh Kamboju
<naresh.kamboju@linaro.org> wrote:
>
> Following kernel warning notices on qemu-arm64, qemu-arm and also on devices
> running Linux version v6.2.0 while running libgpiod tests.
>

I don't see it on v6.2 with libgpiod v1.6.4. Seeing the output of the
test script, it seems you're using an old version - what is it?

> + ./gpiod.sh /opt/libgpiod/bin/

What's in gpiod.sh?

Bart

>   [INFO]    libgpiod test suite
>   [INFO]    117 tests registered
>   [INFO]    checking the linux kernel version
>   [INFO]    kernel release is v6.2.0 - ok to run tests
>   [INFO]    using gpio-tools from '/usr/bin'
> [   10.499036] ------------[ cut here ]------------
> [   10.499656] refcount_t: underflow; use-after-free.
> [   10.500264] WARNING: CPU: 2 PID: 291 at lib/refcount.c:28
> refcount_warn_saturate+0xf4/0x144
> [   10.501306] Modules linked in: gpio_mockup(-) cfg80211 bluetooth
> rfkill crct10dif_ce fuse drm
> [   10.502364] CPU: 2 PID: 291 Comm: gpiod-test Not tainted 6.2.0 #1
> [   10.503229] Hardware name: linux,dummy-virt (DT)
> [   10.503883] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [   10.505331] pc : refcount_warn_saturate+0xf4/0x144
> [   10.505723] lr : refcount_warn_saturate+0xf4/0x144
> [   10.506115] sp : ffff800008983cd0
> [   10.506391] x29: ffff800008983cd0 x28: ffff0000c4c4c100 x27: 0000000000000000
> [   10.506961] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
> [   10.507533] x23: 0000000000000200 x22: ffff0000c4e66800 x21: ffff0000c7734640
> [   10.508104] x20: 0000000000000001 x19: ffff0000c7734600 x18: ffffffffffffffff
> [   10.508677] x17: 3d4d455453595342 x16: ffffcf0234432020 x15: ffff800088983957
> [   10.509424] x14: 0000000000000000 x13: 2e656572662d7265 x12: 7466612d65737520
> [   10.510003] x11: 3b776f6c66726564 x10: ffffcf02365db580 x9 : ffffcf0233b20138
> [   10.510575] x8 : 00000000ffffefff x7 : ffffcf02365db580 x6 : 0000000000000001
> [   10.511145] x5 : ffffcf023655f000 x4 : ffffcf023655f2e8 x3 : 0000000000000000
> [   10.511721] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c4c4c100
> [   10.512294] Call trace:
> [   10.512494]  refcount_warn_saturate+0xf4/0x144
> [   10.512971]  kobject_put+0x164/0x220
> [   10.513224]  fwnode_remove_software_node+0x44/0x60
> [   10.513554]  gpio_mockup_unregister_pdevs+0x54/0x70 [gpio_mockup]
> [   10.513970]  gpio_mockup_exit+0x10/0x328 [gpio_mockup]
> [   10.514322]  __arm64_sys_delete_module+0x190/0x2a0
> [   10.514653]  invoke_syscall+0x50/0x120
> [   10.514915]  el0_svc_common.constprop.0+0x104/0x124
> [   10.515277]  do_el0_svc+0x44/0xcc
> [   10.515541]  el0_svc+0x30/0x94
> [   10.515788]  el0t_64_sync_handler+0xbc/0x13c
> [   10.516126]  el0t_64_sync+0x190/0x194
> [   10.516419] ---[ end trace 0000000000000000 ]---
>
>
> Build and test logs,
> https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/test/ctxless-get-value-single-line/log
> https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/tests/
>
>
> --
> Linaro LKFT
> https://lkft.linaro.org

Re: arm64: libgpiod: refcount_t: underflow; use-after-free.

[Anders Roxell]

On Tue, 21 Feb 2023 at 18:54, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Tue, Feb 21, 2023 at 07:13:31PM +0200, Andy Shevchenko wrote:
> > On Mon, Feb 20, 2023 at 08:29:27PM +0530, Naresh Kamboju wrote:
> > > Following kernel warning notices on qemu-arm64, qemu-arm and also on devices
> > > running Linux version v6.2.0 while running libgpiod tests.
>
> ...
>
> > -             ACPI_COMPANION_SET(&pdev->dev, NULL);
>
> This line should stay otherwise it will remove the device that may share
> the fwnode with this newly created platform device.
>

I was this issue on todays next tag: next-20230607 too, when I ran
libgpiod v1.6.4, and I
trieed to apply your proposed patch, but it didn't solve the
"refcount_t: underflow; use-after-free.".

However, understand that I shouldn't run libgpiod v1.6.4, but I did by
accident. Not sure
that I think I should get a use-after-free if I run the wrong version
of the test-suite or?

Running with libgpiod v2.0.1 I do not see this use-after-free issue.

This is how I reproduced the issue on todays next tag next-20230607, I
use tuxmake [1] to build the kernel and tuxrun [2] to run test with
the booted kernel.
$git checkout next-20230607
$ tuxmake --runtime podman --target-arch arm64 --toolchain gcc-12
--kconfig defconfig --kconfig-add
https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/lkft.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/lkft-crypto.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/distro-overrides.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/systemd.config
--kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-kernel/linux/files/virtio.config
--kconfig-add CONFIG_ARM64_MODULE_PLTS=y --kconfig-add
CONFIG_SYN_COOKIES=y --kconfig-add CONFIG_SCHEDSTATS=y --kconfig-add
CONFIG_GPIOLIB=y --kconfig-add CONFIG_GPIO_CDEV=y --kconfig-add
CONFIG_GPIO_MOCKUP=m --kconfig-add CONFIG_GPIO_SIM=m --results-hook
'tuxrun --runtime podman --device qemu-arm64 --boot-args rw --tuxmake
./ --rootfs https://storage.tuxboot.com/debian/bookworm/arm64/rootfs.ext4.xz
--parameters SKIPFILE=skipfile-lkft.yaml --tests libgpiod --timeouts
boot=30 --overlay
https://storage.dev.tuxboot.com/overlays/debian/bookworm/arm64/libgpiod/v1.6.4/libgpiod.tar.xz
--save-output --log-file -'

Cheers,
Anders
[1] https://tuxmake.org/
[2] https://tuxrun.org/

Re: arm64: libgpiod: refcount_t: underflow; use-after-free.

[Anders Roxell]

On Wed, 22 Feb 2023 at 13:36, Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> On Mon, Feb 20, 2023 at 3:59 PM Naresh Kamboju
> <naresh.kamboju@linaro.org> wrote:
> >
> > Following kernel warning notices on qemu-arm64, qemu-arm and also on devices
> > running Linux version v6.2.0 while running libgpiod tests.
> >
>
> I don't see it on v6.2 with libgpiod v1.6.4. Seeing the output of the
> test script, it seems you're using an old version - what is it?

Yes, I did run libgpiod v1.6.4 by mistake on todays next-20230607 tag.
Not sure if I should or should not get the use-after-free warning by
running the "wrong version"
of a test suite or?

>
> > + ./gpiod.sh /opt/libgpiod/bin/
>
> What's in gpiod.sh?

its a wrapper script around gpiod-test [1] to parse the output to be
understood by our test framework

Cheers,
Anders
[1] https://github.com/Linaro/test-definitions/blob/master/automated/linux/gpiod/gpiod.sh

>
> Bart
>
> >   [INFO]    libgpiod test suite
> >   [INFO]    117 tests registered
> >   [INFO]    checking the linux kernel version
> >   [INFO]    kernel release is v6.2.0 - ok to run tests
> >   [INFO]    using gpio-tools from '/usr/bin'
> > [   10.499036] ------------[ cut here ]------------
> > [   10.499656] refcount_t: underflow; use-after-free.
> > [   10.500264] WARNING: CPU: 2 PID: 291 at lib/refcount.c:28
> > refcount_warn_saturate+0xf4/0x144
> > [   10.501306] Modules linked in: gpio_mockup(-) cfg80211 bluetooth
> > rfkill crct10dif_ce fuse drm
> > [   10.502364] CPU: 2 PID: 291 Comm: gpiod-test Not tainted 6.2.0 #1
> > [   10.503229] Hardware name: linux,dummy-virt (DT)
> > [   10.503883] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> > [   10.505331] pc : refcount_warn_saturate+0xf4/0x144
> > [   10.505723] lr : refcount_warn_saturate+0xf4/0x144
> > [   10.506115] sp : ffff800008983cd0
> > [   10.506391] x29: ffff800008983cd0 x28: ffff0000c4c4c100 x27: 0000000000000000
> > [   10.506961] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
> > [   10.507533] x23: 0000000000000200 x22: ffff0000c4e66800 x21: ffff0000c7734640
> > [   10.508104] x20: 0000000000000001 x19: ffff0000c7734600 x18: ffffffffffffffff
> > [   10.508677] x17: 3d4d455453595342 x16: ffffcf0234432020 x15: ffff800088983957
> > [   10.509424] x14: 0000000000000000 x13: 2e656572662d7265 x12: 7466612d65737520
> > [   10.510003] x11: 3b776f6c66726564 x10: ffffcf02365db580 x9 : ffffcf0233b20138
> > [   10.510575] x8 : 00000000ffffefff x7 : ffffcf02365db580 x6 : 0000000000000001
> > [   10.511145] x5 : ffffcf023655f000 x4 : ffffcf023655f2e8 x3 : 0000000000000000
> > [   10.511721] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c4c4c100
> > [   10.512294] Call trace:
> > [   10.512494]  refcount_warn_saturate+0xf4/0x144
> > [   10.512971]  kobject_put+0x164/0x220
> > [   10.513224]  fwnode_remove_software_node+0x44/0x60
> > [   10.513554]  gpio_mockup_unregister_pdevs+0x54/0x70 [gpio_mockup]
> > [   10.513970]  gpio_mockup_exit+0x10/0x328 [gpio_mockup]
> > [   10.514322]  __arm64_sys_delete_module+0x190/0x2a0
> > [   10.514653]  invoke_syscall+0x50/0x120
> > [   10.514915]  el0_svc_common.constprop.0+0x104/0x124
> > [   10.515277]  do_el0_svc+0x44/0xcc
> > [   10.515541]  el0_svc+0x30/0x94
> > [   10.515788]  el0t_64_sync_handler+0xbc/0x13c
> > [   10.516126]  el0t_64_sync+0x190/0x194
> > [   10.516419] ---[ end trace 0000000000000000 ]---
> >
> >
> > Build and test logs,
> > https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/test/ctxless-get-value-single-line/log
> > https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/tests/
> >
> >
> > --
> > Linaro LKFT
> > https://lkft.linaro.org

Re: arm64: libgpiod: refcount_t: underflow; use-after-free.

[Bartosz Golaszewski]

On Wed, Jun 7, 2023 at 8:35 PM Anders Roxell <anders.roxell@linaro.org> wrote:
>
> On Wed, 22 Feb 2023 at 13:36, Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> >
> > On Mon, Feb 20, 2023 at 3:59 PM Naresh Kamboju
> > <naresh.kamboju@linaro.org> wrote:
> > >
> > > Following kernel warning notices on qemu-arm64, qemu-arm and also on devices
> > > running Linux version v6.2.0 while running libgpiod tests.
> > >
> >
> > I don't see it on v6.2 with libgpiod v1.6.4. Seeing the output of the
> > test script, it seems you're using an old version - what is it?
>
> Yes, I did run libgpiod v1.6.4 by mistake on todays next-20230607 tag.
> Not sure if I should or should not get the use-after-free warning by
> running the "wrong version"
> of a test suite or?
>

It doesn't matter, v1.6.4 is still supported. I'll give it a try tomorrow.

Brt

> >
> > > + ./gpiod.sh /opt/libgpiod/bin/
> >
> > What's in gpiod.sh?
>
> its a wrapper script around gpiod-test [1] to parse the output to be
> understood by our test framework
>
> Cheers,
> Anders
> [1] https://github.com/Linaro/test-definitions/blob/master/automated/linux/gpiod/gpiod.sh
>
> >
> > Bart
> >
> > >   [INFO]    libgpiod test suite
> > >   [INFO]    117 tests registered
> > >   [INFO]    checking the linux kernel version
> > >   [INFO]    kernel release is v6.2.0 - ok to run tests
> > >   [INFO]    using gpio-tools from '/usr/bin'
> > > [   10.499036] ------------[ cut here ]------------
> > > [   10.499656] refcount_t: underflow; use-after-free.
> > > [   10.500264] WARNING: CPU: 2 PID: 291 at lib/refcount.c:28
> > > refcount_warn_saturate+0xf4/0x144
> > > [   10.501306] Modules linked in: gpio_mockup(-) cfg80211 bluetooth
> > > rfkill crct10dif_ce fuse drm
> > > [   10.502364] CPU: 2 PID: 291 Comm: gpiod-test Not tainted 6.2.0 #1
> > > [   10.503229] Hardware name: linux,dummy-virt (DT)
> > > [   10.503883] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> > > [   10.505331] pc : refcount_warn_saturate+0xf4/0x144
> > > [   10.505723] lr : refcount_warn_saturate+0xf4/0x144
> > > [   10.506115] sp : ffff800008983cd0
> > > [   10.506391] x29: ffff800008983cd0 x28: ffff0000c4c4c100 x27: 0000000000000000
> > > [   10.506961] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
> > > [   10.507533] x23: 0000000000000200 x22: ffff0000c4e66800 x21: ffff0000c7734640
> > > [   10.508104] x20: 0000000000000001 x19: ffff0000c7734600 x18: ffffffffffffffff
> > > [   10.508677] x17: 3d4d455453595342 x16: ffffcf0234432020 x15: ffff800088983957
> > > [   10.509424] x14: 0000000000000000 x13: 2e656572662d7265 x12: 7466612d65737520
> > > [   10.510003] x11: 3b776f6c66726564 x10: ffffcf02365db580 x9 : ffffcf0233b20138
> > > [   10.510575] x8 : 00000000ffffefff x7 : ffffcf02365db580 x6 : 0000000000000001
> > > [   10.511145] x5 : ffffcf023655f000 x4 : ffffcf023655f2e8 x3 : 0000000000000000
> > > [   10.511721] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c4c4c100
> > > [   10.512294] Call trace:
> > > [   10.512494]  refcount_warn_saturate+0xf4/0x144
> > > [   10.512971]  kobject_put+0x164/0x220
> > > [   10.513224]  fwnode_remove_software_node+0x44/0x60
> > > [   10.513554]  gpio_mockup_unregister_pdevs+0x54/0x70 [gpio_mockup]
> > > [   10.513970]  gpio_mockup_exit+0x10/0x328 [gpio_mockup]
> > > [   10.514322]  __arm64_sys_delete_module+0x190/0x2a0
> > > [   10.514653]  invoke_syscall+0x50/0x120
> > > [   10.514915]  el0_svc_common.constprop.0+0x104/0x124
> > > [   10.515277]  do_el0_svc+0x44/0xcc
> > > [   10.515541]  el0_svc+0x30/0x94
> > > [   10.515788]  el0t_64_sync_handler+0xbc/0x13c
> > > [   10.516126]  el0t_64_sync+0x190/0x194
> > > [   10.516419] ---[ end trace 0000000000000000 ]---
> > >
> > >
> > > Build and test logs,
> > > https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/test/ctxless-get-value-single-line/log
> > > https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/14856342/suite/libgpiod/tests/
> > >
> > >
> > > --
> > > Linaro LKFT
> > > https://lkft.linaro.org