Re: [PATCH] wifi: ath11k: fix rx completion meta data corruption

[Johan Hovold <johan@kernel.org>]

On Sat, Mar 22, 2025 at 03:32:08PM -0500, Steev Klimaszewski wrote:
> On Fri, Mar 21, 2025 at 9:55 AM Johan Hovold <johan+linaro@kernel.org> wrote:
> >
> > Add the missing memory barrier to make sure that the REO dest ring
> > descriptor is read after the head pointer to avoid using stale data on
> > weakly ordered architectures like aarch64.
> >
> > This may fix the ring-buffer corruption worked around by commit
> > f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination
> > ring") by silently discarding data, and may possibly also address user
> > reported errors like:
> >
> >         ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set
> >
> > Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41
> >
> > Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
> > Cc: stable@vger.kernel.org      # 5.6
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=218005
> > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> > ---
> >
> > As I reported here:
> >
> >         https://lore.kernel.org/lkml/Z9G5zEOcTdGKm7Ei@hovoldconsulting.com/
> >
> > the ath11k and ath12k appear to be missing a number of memory barriers
> > that are required on weakly ordered architectures like aarch64 to avoid
> > memory corruption issues.
> >
> > Here's a fix for one more such case which people already seem to be
> > hitting.
> >
> > Note that I've seen one "msdu_done" bit not set warning also with this
> > patch so whether it helps with that at all remains to be seen. I'm CCing
> > Jens and Steev that see these warnings frequently and that may be able
> > to help out with testing.

> While the fix is definitely a fix, it does not seem to help with the
> `msdu_done bit in attention is not set` message as I have seen it 43
> times in the last 12 hours.

Thanks for testing, Steev. Given that that the patch makes the warnings
go away in Clayton's setup it seems we may be dealing with more than
once root cause here.

Johan