Linux regressions report for mainline [2024-03-10]

[Thorsten Leemhuis]

Hi Linus, here is a quick status update wrt. to regressions introduced
in this cycle. This time hand-complied instead of from regzbot (I just
broke something and lack time to fix it):


# Things that might or might not be a good reason for a -rc8

* Btrfs since v6.8-rc6 has a fiemap regression that "can actually have
serious consequences", as mentioned in
https://lore.kernel.org/linux-btrfs/cover.1709202499.git.fdmanana@xxxxxxxx/
The fixes in reply to that mail since Wednesday are in -next as
978b63f7464abc ("btrfs: fix race when detecting delalloc ranges during
fiemap") and 1cab1375ba6d53 ("btrfs: reuse cloned extent buffer during
fiemap to avoid re-allocations"), but not on the way to you afaics.

* A fix for Johan Hovold's last big Lenovo ThinkPad X13s regression
(hard resets disconnecting external displays) is currently up for review
and testing:
https://lore.kernel.org/lkml/ZeyOmJLlBbwnmaJN@xxxxxxxxxxxxxxxxxxxx/



# Fixes for regressions from this cycle afaics unlikely to reach 6.8

* -next commit 3445139e3a594b ("Revert "Revert "md/raid5: Wait for
MD_SB_CHANGE_PENDING in raid5d"""), which reverts a commit from
6.8-rc1; Song thinks it's better to merge it for 6.9 and then backport
to 6.8:
https://lore.kernel.org/all/CAPhsuW51ND4qH4My8Uz1XaZSdvAjDR7eL7O-RLr5wKmFJA0XMQ@xxxxxxxxxxxxxx/
Report: https://lore.kernel.org/all/20240123005700.9302-1-dan@xxxxxxxx/

* -next commit 0d7dfc79fb9b4b ("drm/msm/a6xx: specify UBWC config for
sc7180" No reply to my recent inquiry why this fix for a commit from
this cycle was queued for 6.9:
https://lore.kernel.org/all/4e55f6fd-8875-4a61-9070-f0ecad8082ea@xxxxxxxxxxxxx/
Report: https://gitlab.freedesktop.org/drm/msm/-/issues/49 and
https://lore.kernel.org/all/85581fad-da8f-4550-a1c8-8f2996425dcd@xxxxxxxxx/


# Regressions fixes sitting on the list awaiting review

* "drm/nouveau: keep DMA buffers required for suspend/resume", which
fixes rendering freezes with multi-GPU setups:
https://lore.kernel.org/dri-devel/20240229175822.30613-1-sidpranjale127@xxxxxxxxxxxxxx/

* "Fix divide-by-zero on DP unplug with nouveau" which fixes a divide error:
https://lore.kernel.org/regressions/ZeoAPFIF6NClUl4P@debian.local/

* "u64_stats: fix u64_stats_init() for lockdep when used repeatedly in
one file" fixes a lockdep splat
https://lore.kernel.org/lkml/20240306111157.29327-1-petr@xxxxxxxxxxx/


# Regression reports where no fix is in sight afaics

* dmaengine: CPU stalls while loading bluetooth module
https://lore.kernel.org/lkml/ZYhQ2-OnjDgoqjvt@xxxxxxx/ and
https://lore.kernel.org/lkml/1553a526-6f28-4a68-88a8-f35bd22d9894@xxxxxxxxxxx/
See also:
https://lore.kernel.org/all/000001da7140%246a0f1570%243e2d4050%24@xxxxxxxxxxx/
Revert might be counter-productive.

* x86/mm/ident_map: kexec now leads to reboot
https://lore.kernel.org/stable/3a1b9909-45ac-4f97-ad68-d16ef1ce99db@xxxxxxxxxxxxxxx/
https://lore.kernel.org/all/CAJbxNHe3EJ88ABB1aZ8bYZq=a36F0TFST1Fqu4fkugvyU_fjhw@xxxxxxxxxxxxxx/
A revert apparently could fix this.



Ciao, Thorsten