Re: bug in mmc driver

From: Ian Lepore <ian_at_freebsd.org>
Date: Fri, 29 Oct 2021 18:34:48 UTC
On Fri, 2021-10-29 at 10:02 +0530, Kamal R. Prasad wrote:
> hello,
> 
> if i run a stress test on a freebsd system booted from a micron mmc
> device, and run a script which in a loop opens the same mmc device in
> read-only mode, it causes a problem in acquiring the bus and panics
> the box. both the stress test and a script to open the mmc device in
> read only mode are in user space and so kernel should not have
> panic'ed. Pl see stack trace from our freebsd derived os.
> 
> thanks
> -kamal
> --------------
> 
> panic: mmc: host bridge didn't serialize us.
> 
> [...]
> 

This indicates a problem in the low-level mmc/sd controller ("host
bridge") driver.  You didn't say anything about what hardware is in
use; I have no idea what driver to look at.

-- Ian