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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 004/191] iio: pressure: bmp280: Tolerate IRQ before registering
Date:   Mon, 29 Jun 2020 11:37:00 -0400
Message-Id: <20200629154007.2495120-5-sashal@kernel.org>
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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit 97b31a6f5fb95b1ec6575b78a7240baddba34384 ]

With DEBUG_SHIRQ enabled we have a kernel crash

[  116.482696] BUG: kernel NULL pointer dereference, address: 0000000000000000

...

[  116.606571] Call Trace:
[  116.609023]  <IRQ>
[  116.611047]  complete+0x34/0x50
[  116.614206]  bmp085_eoc_irq+0x9/0x10 [bmp280]

because DEBUG_SHIRQ mechanism fires an IRQ before registration and drivers
ought to be able to handle an interrupt happening before request_irq() returns.

Fixes: aae953949651 ("iio: pressure: bmp280: add support for BMP085 EOC interrupt")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/pressure/bmp280-core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index c9263acc190b6..36f03fdf4d4f9 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -630,7 +630,7 @@ static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas)
 	unsigned int ctrl;
 
 	if (data->use_eoc)
-		init_completion(&data->done);
+		reinit_completion(&data->done);
 
 	ret = regmap_write(data->regmap, BMP280_REG_CTRL_MEAS, ctrl_meas);
 	if (ret)
@@ -886,6 +886,9 @@ static int bmp085_fetch_eoc_irq(struct device *dev,
 			"trying to enforce it\n");
 		irq_trig = IRQF_TRIGGER_RISING;
 	}
+
+	init_completion(&data->done);
+
 	ret = devm_request_threaded_irq(dev,
 			irq,
 			bmp085_eoc_irq,
-- 
2.25.1