[PATCH v2 05/10] spi: bcm2835: Drop dma_pending flag

[Marc Kleine-Budde]

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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