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However this may cause a deadlock if we create the auxiliary shared proxy devices with this lock taken. We only need to protect entry->offset while it's read/written so shorten the critical section and release the lock before creating the proxy device as the field in question is no longer accessed at this point. Fixes: 710abda58055 ("gpio: shared: call gpio_chip::of_xlate() if set") Reported-by: Dmitry Baryshkov Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib-shared.c | 56 +++++++++++++++++++++------------------= ---- 1 file changed, 28 insertions(+), 28 deletions(-) diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c index e257212fa5e3df249de0d06eebdb2165ae734ebc..e02d6b93a4ab42b197f0fd64e48= 54a303f54f140 100644 --- a/drivers/gpio/gpiolib-shared.c +++ b/drivers/gpio/gpiolib-shared.c @@ -533,48 +533,48 @@ int gpiochip_setup_shared(struct gpio_chip *gc) * exposing shared pins. Find them and create the proxy devices. */ list_for_each_entry(entry, &gpio_shared_list, list) { - guard(mutex)(&entry->lock); - if (!device_match_fwnode(&gdev->dev, entry->fwnode)) continue; =20 if (list_count_nodes(&entry->refs) <=3D 1) continue; =20 + scoped_guard(mutex, &entry->lock) { #if IS_ENABLED(CONFIG_OF) - if (is_of_node(entry->fwnode) && gc->of_xlate) { - /* - * This is the earliest that we can tranlate the - * devicetree offset to the chip offset. - */ - struct of_phandle_args gpiospec =3D { }; + if (is_of_node(entry->fwnode) && gc->of_xlate) { + /* + * This is the earliest that we can tranlate the + * devicetree offset to the chip offset. + */ + struct of_phandle_args gpiospec =3D { }; =20 - gpiospec.np =3D to_of_node(entry->fwnode); - gpiospec.args_count =3D 2; - gpiospec.args[0] =3D entry->offset; + gpiospec.np =3D to_of_node(entry->fwnode); + gpiospec.args_count =3D 2; + gpiospec.args[0] =3D entry->offset; =20 - ret =3D gc->of_xlate(gc, &gpiospec, NULL); - if (ret < 0) - return ret; + ret =3D gc->of_xlate(gc, &gpiospec, NULL); + if (ret < 0) + return ret; =20 - entry->offset =3D ret; - } + entry->offset =3D ret; + } #endif /* CONFIG_OF */ =20 - desc =3D &gdev->descs[entry->offset]; + desc =3D &gdev->descs[entry->offset]; =20 - __set_bit(GPIOD_FLAG_SHARED, &desc->flags); - /* - * Shared GPIOs are not requested via the normal path. Make - * them inaccessible to anyone even before we register the - * chip. - */ - ret =3D gpiod_request_commit(desc, "shared"); - if (ret) - return ret; + __set_bit(GPIOD_FLAG_SHARED, &desc->flags); + /* + * Shared GPIOs are not requested via the normal path. Make + * them inaccessible to anyone even before we register the + * chip. + */ + ret =3D gpiod_request_commit(desc, "shared"); + if (ret) + return ret; =20 - pr_debug("GPIO %u owned by %s is shared by multiple consumers\n", - entry->offset, gpio_device_get_label(gdev)); + pr_debug("GPIO %u owned by %s is shared by multiple consumers\n", + entry->offset, gpio_device_get_label(gdev)); + } =20 list_for_each_entry(ref, &entry->refs, list) { pr_debug("Setting up a shared GPIO entry for %s (con_id: '%s')\n", --- base-commit: 85964cdcad0fac9a0eb7b87a0f9d88cc074b854c change-id: 20260325-gpio-shared-deadlock-b63622a86ce1 Best regards, --=20 Bartosz Golaszewski