From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Stefan Wahren <stefan.wahren@i2se.com>
Cc: "linux-rpi-kernel@lists.infradead.org"
<linux-rpi-kernel@lists.infradead.org>,
Lukas Wunner <lukas@wunner.de>,
linux-spi@vger.kernel.org,
Florian Fainelli <f.fainelli@gmail.com>
Subject: Re: [PATCH v2 05/10] spi: bcm2835: Drop dma_pending flag
Date: Tue, 19 Jul 2022 09:45:03 +0200 [thread overview]
Message-ID: <20220719074503.n3csrhq4553zubdu@pengutronix.de> (raw)
In-Reply-To: <5e0e595d-dd5d-b1d9-ca25-82b6f6a029e5@i2se.com>
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On 19.07.2022 09:34:45, Stefan Wahren wrote:
> Am 19.07.22 um 08:52 schrieb Marc Kleine-Budde:
> > The question is: Why runs the IRQ based transfer into a timeout? The
> > kernel that produces the crash has ecfbd3cf3b8b ("spi: bcm2835: Enable
> > shared interrupt support") applied (which was reverted on mainline in a
> > later patch).
>
> thank for your report. Unfortunately i don't have an answer to your
> question, but maybe this is related:
Sorry, that question was rhetorical. The kernel that produced this crash
was too old, it has support for the shared SPI interrupts ecfbd3cf3b8b
("spi: bcm2835: Enable shared interrupt support"), but misses the fix
commit 46feb7d7241b ("spi: bcm2835: Fix for shared interrupts").
With the 46feb7d7241b ("spi: bcm2835: Fix for shared interrupts") SPI
transmit timeout doesn't happen any more and thus the NULL pointer
deref is not triggered.
> https://github.com/raspberrypi/linux/commit/c643a3603dcbe6d0feada33915cef1ef896b865e
>
> > I'll create a patch to fix the NULL pointer deref. As a interrupt based
> > transfer might run into a timeout for other reasons, too. So better
> > avoid a kernel crash in that case.
>
> Yes, please
Done:
https://lore.kernel.org/all/20220719072234.2782764-1-mkl@pengutronix.de
regards,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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next prev parent reply other threads:[~2022-07-19 7:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 10:15 [PATCH v2 00/10] Speed up SPI simplex transfers on Raspberry Pi Lukas Wunner
[not found] ` <cover.1568187525.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2019-09-11 10:15 ` [PATCH v2 04/10] spi: bcm2835: Work around DONE bit erratum Lukas Wunner
[not found] ` <7ceb98f154cdcf72c577615fa312df41adea5f47.1568187525.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2019-09-11 11:25 ` Mark Brown
2019-09-11 10:15 ` [PATCH v2 07/10] spi: bcm2835: Speed up TX-only DMA transfers by clearing RX FIFO Lukas Wunner
2019-09-11 10:15 ` [PATCH v2 06/10] spi: bcm2835: Cache CS register value for ->prepare_message() Lukas Wunner
2019-09-11 10:15 ` [PATCH v2 01/10] dmaengine: bcm2835: Allow reusable descriptors Lukas Wunner
2019-09-11 10:15 ` [PATCH v2 09/10] dmaengine: bcm2835: Avoid accessing memory when copying zeroes Lukas Wunner
2019-09-11 10:15 ` [PATCH v2 10/10] spi: bcm2835: Speed up RX-only DMA transfers by zero-filling TX FIFO Lukas Wunner
2019-09-11 10:15 ` [PATCH v2 05/10] spi: bcm2835: Drop dma_pending flag Lukas Wunner
2022-07-19 6:52 ` Marc Kleine-Budde
2022-07-19 7:34 ` Stefan Wahren
2022-07-19 7:45 ` Marc Kleine-Budde [this message]
2019-09-11 10:15 ` [PATCH v2 08/10] dmaengine: bcm2835: Document struct bcm2835_dmadev Lukas Wunner
2019-09-11 10:15 ` [PATCH v2 02/10] dmaengine: bcm2835: Allow cyclic transactions without interrupt Lukas Wunner
2019-09-11 10:15 ` [PATCH v2 03/10] spi: Guarantee cacheline alignment of driver-private data Lukas Wunner
[not found] ` <01625b9b26b93417fb09d2c15ad02dfe9cdbbbe5.1568187525.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2019-09-11 14:59 ` Applied "spi: Guarantee cacheline alignment of driver-private data" to the spi tree Mark Brown
2019-09-11 10:47 ` [PATCH v2 00/10] Speed up SPI simplex transfers on Raspberry Pi Mark Brown
[not found] ` <20190911114352.w2htkzfi5v6zl7nq@wunner.de>
[not found] ` <20190911114352.w2htkzfi5v6zl7nq-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2019-09-11 11:59 ` Mark Brown
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