Re: Spurious problems when running regmap unit tests in qemu

[Guenter Roeck]

On Mon, Feb 05, 2024 at 10:03:04AM -0800, Guenter Roeck wrote:
> Hi,
> 
> I am observing spurious regmap unit test failures in my qemu test runs.
> Examples:
> 
>   # raw_noinc_write: ASSERTION FAILED at drivers/base/regmap/regmap-kunit.c:1243
>   Expected val_test == val, but
>       val_test == 65581 (0x1002d)
>       val == 45 (0x2d)
>       not ok 8 maple-big
>   # raw_noinc_write: pass:7 fail:1 skip:0 total:8
> 
>   or
> 
>   # raw_noinc_write: ASSERTION FAILED at drivers/base/regmap/regmap-kunit.c:1243
>   Expected val_test == val, but
>       val_test == 65556 (0x10014)
>       val == 20 (0x14)
>       not ok 5 rbtree-little
>       ok 6 rbtree-big
>       ok 7 maple-little
>       ok 8 maple-big
>   # raw_noinc_write: pass:7 fail:1 skip:0 total:8
> 
> The problem is not seen all the time. I see it with various qemu machines,
> but not always the same. Endianness does not seem to make a difference.
> The failure is always in raw_noinc_write. So far, I have observed the
> following individual test failures:
> 
> not ok 2 none-big
> not ok 4 flat-big
> not ok 5 rbtree-little
> not ok 8 maple-big
> 
> The most recent test run (on v6.8-rc3) failed on the following
> architectures and machines (again, those are not always the same).
> 
> arm:npcm750-evb:regmap
> mips:malta:regmap
> mipsel64:malta:regmap
> i386:q35:regmap
> 
> I only recently started to track unit test failures, so I don't know yet
> if this problem has been introduced recently or if it has existed since
> the tests were introduced.
> 

Actually, the failing test _was_ introduced in v6.8-rc1 with commmit
d958d97848a6 ("regmap: kunit: add noinc write test"). Copying the author.

Guenter