From: Dan Carpenter <dan.carpenter@linaro.org>
To: bartosz.golaszewski@linaro.org
Cc: linux-wireless@vger.kernel.org, linux-input@vger.kernel.org
Subject: [bug report] gpiolib: use a mutex to protect the list of GPIO devices
Date: Mon, 15 Jan 2024 11:50:52 +0300 [thread overview]
Message-ID: <f7b5ff1e-8f34-4d98-a7be-b826cb897dc8@moroto.mountain> (raw)
Hello Bartosz Golaszewski,
The patch 65a828bab158: "gpiolib: use a mutex to protect the list of
GPIO devices" from Dec 15, 2023 (linux-next), leads to the following
Smatch static checker warning:
drivers/net/wireless/ath/ath9k/hw.c:2836 ath9k_hw_gpio_get()
warn: sleeping in atomic context
drivers/net/wireless/ath/ath9k/hw.c
2826 val = MS_REG_READ(AR9285, gpio);
2827 else if (AR_SREV_9280(ah))
2828 val = MS_REG_READ(AR928X, gpio);
2829 else if (AR_DEVID_7010(ah))
2830 val = REG_READ(ah, AR7010_GPIO_IN) & BIT(gpio);
2831 else if (AR_SREV_9300_20_OR_LATER(ah))
2832 val = REG_READ(ah, AR_GPIO_IN(ah)) & BIT(gpio);
2833 else
2834 val = MS_REG_READ(AR, gpio);
2835 } else if (BIT(gpio) & ah->caps.gpio_requested) {
--> 2836 val = gpio_get_value(gpio) & BIT(gpio);
^^^^^^^^^^^^^^
2837 } else {
2838 WARN_ON(1);
2839 }
2840
2841 return !!val;
2842 }
Before gpio_get_value() took a spinlock but now it takes a mutex
(actually a rw semaphor now). The call tree where we are in atomic
context is:
ath_btcoex_period_timer() <- disables preempt
-> ath_detect_bt_priority()
-> ath9k_hw_gpio_get()
Another warning this change causes is:
drivers/input/keyboard/matrix_keypad.c:95 enable_row_irqs() warn: sleeping in atomic context
matrix_keypad_scan() <- disables preempt
-> enable_row_irqs()
drivers/input/keyboard/matrix_keypad.c:108 disable_row_irqs() warn: sleeping in atomic context
matrix_keypad_interrupt() <- disables preempt
-> disable_row_irqs()
regards,
dan carpenter
next reply other threads:[~2024-01-15 8:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-15 8:50 Dan Carpenter [this message]
2024-01-15 9:18 ` [bug report] gpiolib: use a mutex to protect the list of GPIO devices Bartosz Golaszewski
2024-01-20 21:06 ` Dmitry Torokhov
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