Re: [PATCH] eeprom: at25: convert to spi-mem API

[Sverdlin, Alexander]

Hi Christophe,

On Mon, 2025-11-03 at 23:36 +0100, Christophe Leroy wrote:
> > > > > > Replace the RAW SPI accesses with spi-mem API. The latter will fall back to
> > > > > > RAW SPI accesses if spi-mem callbacks are not implemented by a controller
> > > > > > driver.
> > > > > 
> > > > > With this patch (kernel v6.17.1) our powerpc boards are totally
> > > > > unstable, we get multiple random Oops due to bad memory accesses.
> > > > > 
> > > > > With this commit reverted the board is stable again.
> > > > > 
> > > > > The SPI driver is:
> > > > > 
> > > > > CONFIG_SPI=y
> > > > > CONFIG_SPI_MASTER=y
> > > > > CONFIG_SPI_MEM=y
> > > > > CONFIG_SPI_FSL_LIB=y
> > > > > CONFIG_SPI_FSL_CPM=y
> > > > > CONFIG_SPI_FSL_SPI=y
> > > > > 
> > > > > How can we further investigate the issue ?
> > > > 
> > > > could you share these "random Oops"?
> > > 
> > > Sure. At the first place they look unrelated. Something is likely
> > 
> > indeed, no obvious connection... Do you have a chance to run KASAN?
> 
> I ran KASAN, it found an overrun in the loop in 
> fsl_spi_cpm_bufs_complete() when t->len is odd, but once fixed the 
> random problem is still there.

thanks for the quick reply!
That sounds promising already!

Do you have a chance to run with CONFIG_DEBUG_STACKOVERFLOW=y ?

-- 
Alexander Sverdlin
Siemens AG
www.siemens.com