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From: kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org
To: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>,
	Stefan Wahren <stefan.wahren-eS4NqCHxEME@public.gmane.org>,
	Hubert Denkmair
	<h.denkmair-4pT7WzY1KUiELgA04lAiVw@public.gmane.org>,
	linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: [PATCH V2 2/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo
Date: Sun, 24 Mar 2019 17:49:55 +0000	[thread overview]
Message-ID: <20190324175002.28969-3-kernel@martin.sperl.org> (raw)
In-Reply-To: <20190324175002.28969-1-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>

From: Martin Sperl <kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>

This read of the fifo is a potential candidate for a race condition
as the spi transfer is not necessarily finished and so can lead to
an early read of the fifo that still misses data.

So it has been removed.

Fixes: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e

Suggested-by: Hubert Denkmair <h.denkmair-4pT7WzY1KUiELgA04lAiVw@public.gmane.org>
Signed-off-by: Martin Sperl <kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
---
 drivers/spi/spi-bcm2835aux.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 41366d0a16af..0838dbda57c7 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -194,13 +194,6 @@ static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs)
 		  BCM2835_AUX_SPI_STAT_TX_FULL))) {
 		bcm2835aux_wr_fifo(bs);
 	}
-
-	/* and check if we have reached "done" */
-	while (bs->rx_len &&
-	       (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
-		  BCM2835_AUX_SPI_STAT_BUSY))) {
-		bcm2835aux_rd_fifo(bs);
-	}
 }

 static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)
--
2.11.0

WARNING: multiple messages have this Message-ID (diff)
From: kernel@martin.sperl.org
To: Mark Brown <broonie@kernel.org>, Eric Anholt <eric@anholt.net>,
	Stefan Wahren <stefan.wahren@i2se.com>,
	Hubert Denkmair <h.denkmair@intence.de>,
	linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Cc: Martin Sperl <kernel@martin.sperl.org>
Subject: [PATCH V2 2/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo
Date: Sun, 24 Mar 2019 17:49:55 +0000	[thread overview]
Message-ID: <20190324175002.28969-3-kernel@martin.sperl.org> (raw)
In-Reply-To: <20190324175002.28969-1-kernel@martin.sperl.org>

From: Martin Sperl <kernel@martin.sperl.org>

This read of the fifo is a potential candidate for a race condition
as the spi transfer is not necessarily finished and so can lead to
an early read of the fifo that still misses data.

So it has been removed.

Fixes: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e

Suggested-by: Hubert Denkmair <h.denkmair@intence.de>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
---
 drivers/spi/spi-bcm2835aux.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 41366d0a16af..0838dbda57c7 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -194,13 +194,6 @@ static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs)
 		  BCM2835_AUX_SPI_STAT_TX_FULL))) {
 		bcm2835aux_wr_fifo(bs);
 	}
-
-	/* and check if we have reached "done" */
-	while (bs->rx_len &&
-	       (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
-		  BCM2835_AUX_SPI_STAT_BUSY))) {
-		bcm2835aux_rd_fifo(bs);
-	}
 }

 static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)
--
2.11.0

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  parent reply	other threads:[~2019-03-24 17:49 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-24 17:49 [PATCH V2 0/9] spi: bcm2835aux: bug fixes and improvements kernel
2019-03-24 17:49 ` kernel
2019-03-24 17:49 ` [PATCH V2 3/9] spi: bcm2835aux: use BCM2835_AUX_SPI_STAT_RX_LVL kernel
2019-03-24 17:49   ` kernel
2019-03-25  9:52   ` Stefan Wahren
2019-03-25  9:52     ` Stefan Wahren
2019-03-24 17:49 ` [PATCH V2 6/9] spi: bcm2835aux: warn in dmesg that native cs is not really supported kernel
2019-03-24 17:49   ` kernel
2019-03-25 10:28   ` Stefan Wahren
2019-03-25 10:28     ` Stefan Wahren
     [not found] ` <20190324175002.28969-1-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
2019-03-24 17:49   ` [PATCH V2 1/9] spi: bcm2835aux: unifying code between polling and interrupt driven code kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:49     ` kernel
2019-03-24 17:49   ` kernel-TqfNSX0MhmxHKSADF0wUEw [this message]
2019-03-24 17:49     ` [PATCH V2 2/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo kernel
2019-03-24 17:49   ` [PATCH V2 4/9] spi: bcm2835aux: remove dead code kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:49     ` kernel
2019-03-24 17:49   ` [PATCH V2 5/9] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:49     ` kernel
2019-03-24 17:50   ` [PATCH V2 7/9] spi: bcm2835aux: setup gpio-cs to output and correct level during setup kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:50     ` kernel
2019-03-24 17:50   ` [PATCH V2 8/9] spi: bcm2835aux: add driver stats to debugfs kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:50     ` kernel
2019-03-25  9:28     ` Stefan Wahren
2019-03-25  9:28       ` Stefan Wahren
2019-03-25  9:52       ` kernel
2019-03-25 10:06         ` Stefan Wahren
2019-03-25 10:11           ` kernel
2019-03-25 10:45             ` Stefan Wahren
2019-03-24 17:50   ` [PATCH V2 9/9] spi: bcm2835aux: make the polling duration limits configurable kernel-TqfNSX0MhmxHKSADF0wUEw
2019-03-24 17:50     ` kernel
2019-03-25  9:44     ` Stefan Wahren
2019-03-25  9:44       ` Stefan Wahren
2019-03-25  9:49       ` kernel
2019-03-25  9:49         ` kernel
2019-03-25  9:59         ` Stefan Wahren
2019-03-25  9:59           ` Stefan Wahren

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