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/... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/...
-- Linaro LKFT https://lkft.linaro.org
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/... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/...
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); }
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.
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-ke... --kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-ke... --kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-ke... --kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-ke... --kconfig-add https://raw.githubusercontent.com/Linaro/meta-lkft/kirkstone/meta/recipes-ke... --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... --save-output --log-file -'
Cheers, Anders [1] https://tuxmake.org/ [2] https://tuxrun.org/
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/... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/...
-- Linaro LKFT https://lkft.linaro.org
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...
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/... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/...
-- Linaro LKFT https://lkft.linaro.org
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...
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/... https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.2/testrun/...
-- Linaro LKFT https://lkft.linaro.org
-
Anders Roxell -
Andy Shevchenko -
Bartosz Golaszewski -
Naresh Kamboju