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

From: Christophe Leroy
Date: Mon Nov 03 2025 - 17:50:19 EST




Le 03/11/2025 à 23:29, Sverdlin, Alexander a écrit :
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Hi Christophe,

On Mon, 2025-11-03 at 22:46 +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.

Christophe