Re: X stopped working with 5.14 on iBook
On 10/14/21 9:21 PM, Stan Johnson wrote:
> ...
> Debian's 5.10.0-8 config file works (as expected) with Debian's 5.10.0-8
> kernel source.
> ...
> X works with 5.14 using a tuned config file derived from 5.13 testing.
> ...
Update:
The issue originally reported by Riccardo Mottola was that X wasn't
working on a PowerBook G4 using Debian's default
vmlinux-5.14.0-2-powerpc kernel. I was able to confirm that the X
failure also occurs on a G4 Cube. My G4 Cube has Debian SID,
sysvinit-core, Xfce and wdm installed. To test whether X works, I
disabled wdm, then I log in at the text console and run "startx". When X
fails, the screen goes blank and the backlight stays on; when X works,
the normal desktop comes up.
X works in mainline v5.12 built using a config file based on Debian's
config-5.10.0-8-powerpc.
X fails in mainline v5.13 built using a config file based on Debian's
config-5.10.0-8-powerpc.
With much help and advice from Finn Thain, I was able to run a bisect
using a config file based on Debian's config-5.10.0-8-powerpc, with
v5.12 "good" and v5.13 "bad".
$ git reset --hard
HEAD is now at 62fb9874f5da Linux 5.13
$ git bisect start v5.13
Updating files: 100% (12992/12992), done.
Previous HEAD position was 62fb9874f5da Linux 5.13
HEAD is now at 9f4ad9e425a1 Linux 5.12
$ git bisect bad v5.13
$ git bisect good v5.12
Bisecting: 8739 revisions left to test after this (roughly 13 steps)
>85f3f17b5db2dd9f8a094a0ddc665555135afd22] Merge branch 'md-fixes' of
https://git.kernel.org/pub/scm/linux/kernel/git/song/md into block-5.13
After the bisect, git reports this:
----------
d3ccc9781560af051554017c702631560bdc0811 is the first bad commit
commit d3ccc9781560af051554017c702631560bdc0811
Author: Christopher M. Riedl <cmr@codefail.de>
Date: Fri Feb 26 19:12:59 2021 -0600
powerpc/signal: Use __get_user() to copy sigset_t
Usually sigset_t is exactly 8B which is a "trivial" size and does not
warrant using __copy_from_user(). Use __get_user() directly in
anticipation of future work to remove the trivial size optimizations
from __copy_from_user().
The ppc32 implementation of get_sigset_t() previously called
copy_from_user() which, unlike __copy_from_user(), calls access_ok().
Replacing this w/ __get_user() (no access_ok()) is fine here since both
callsites in signal_32.c are preceded by an earlier access_ok().
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-11-cmr@codefail.de
arch/powerpc/kernel/signal.h | 7 +++++++
arch/powerpc/kernel/signal_32.c | 2 +-
arch/powerpc/kernel/signal_64.c | 4 ++--
3 files changed, 10 insertions(+), 3 deletions(-)
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