Messages in this thread Patch in this message | | | Date | Tue, 18 May 2021 15:32:41 +0300 | From | Matti Vaittinen <> | Subject | [PATCH v2 3/5] extcon: extcon-max77693.c: Fix potential work-queue cancellation race |
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The extcon IRQ schedules a work item. IRQ is requested using devm while WQ is cancelld at remove(). This mixing of devm and manual unwinding has potential case where the WQ has been emptied (.remove() was ran) but devm unwinding of IRQ was not yet done. It may be possible the IRQ is triggered at this point scheduling new work item to the already flushed queue.
According to the input documentation the input device allocated by devm_input_allocate_device() does not need to be explicitly unregistered. Use the new devm_work_autocancel() and remove the remove() to simplify the code.
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> ---
Please note that the change is compile-tested only. All proper testing is highly appreciated. --- drivers/extcon/extcon-max77693.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-)
diff --git a/drivers/extcon/extcon-max77693.c b/drivers/extcon/extcon-max77693.c index 92af97e00828..1f1d9ab0c5c7 100644 --- a/drivers/extcon/extcon-max77693.c +++ b/drivers/extcon/extcon-max77693.c @@ -5,6 +5,7 @@ // Copyright (C) 2012 Samsung Electrnoics // Chanwoo Choi <cw00.choi@samsung.com> +#include <linux/devm-helpers.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/i2c.h> @@ -1127,7 +1128,10 @@ static int max77693_muic_probe(struct platform_device *pdev) platform_set_drvdata(pdev, info); mutex_init(&info->mutex); - INIT_WORK(&info->irq_work, max77693_muic_irq_work); + ret = devm_work_autocancel(&pdev->dev, &info->irq_work, + max77693_muic_irq_work); + if (ret) + return ret; /* Support irq domain for MAX77693 MUIC device */ for (i = 0; i < ARRAY_SIZE(muic_irqs); i++) { @@ -1254,22 +1258,11 @@ static int max77693_muic_probe(struct platform_device *pdev) return ret; } -static int max77693_muic_remove(struct platform_device *pdev) -{ - struct max77693_muic_info *info = platform_get_drvdata(pdev); - - cancel_work_sync(&info->irq_work); - input_unregister_device(info->dock); - - return 0; -} - static struct platform_driver max77693_muic_driver = { .driver = { .name = DEV_NAME, }, .probe = max77693_muic_probe, - .remove = max77693_muic_remove, }; module_platform_driver(max77693_muic_driver); -- 2.25.4
-- Matti Vaittinen, Linux device drivers ROHM Semiconductors, Finland SWDC Kiviharjunlenkki 1E 90220 OULU FINLAND
~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~ Simon says - in Latin please. ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~ Thanks to Simon Glass for the translation =] [unhandled content-type:application/pgp-signature] | |