* Re: [Bug 203597] New: kernel 4.9.175 fails to boot on a PowerMac G4 3,6 at early stage
[not found] <bug-203597-206035@https.bugzilla.kernel.org/>
@ 2019-05-14 4:56 ` Christophe Leroy
2019-05-14 7:05 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Christophe Leroy @ 2019-05-14 4:56 UTC (permalink / raw)
To: Greg KH; +Cc: linuxppc-dev, erhard_f, stable
Hi Greg,
Could you please apply b45ba4a51cde29b2939365ef0c07ad34c8321789 to 4.9
since 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 was applied allthought
marked for #4.13+
Thanks
Christophe
Le 13/05/2019 à 22:18, bugzilla-daemon@bugzilla.kernel.org a écrit :
> https://bugzilla.kernel.org/show_bug.cgi?id=203597
>
> Bug ID: 203597
> Summary: kernel 4.9.175 fails to boot on a PowerMac G4 3,6 at
> early stage
> Product: Platform Specific/Hardware
> Version: 2.5
> Kernel Version: 4.9.175
> Hardware: PPC-32
> OS: Linux
> Tree: Mainline
> Status: NEW
> Severity: normal
> Priority: P1
> Component: PPC-32
> Assignee: platform_ppc-32@kernel-bugs.osdl.org
> Reporter: erhard_f@mailbox.org
> Regression: No
>
> Created attachment 282743
> --> https://bugzilla.kernel.org/attachment.cgi?id=282743&action=edit
> kernel .config (PowerMac G4 MDD)
>
> Trying out older kernels on the G4 MDD I noticed recent 4.9.x freeze the
> machine. Only message displayed in black letters on a white screen:
>
> done
> found display : /pco@f0000000/ATY,AlteracParent@10/ATY,Alterac_B@1,
> opening...
>
>
> It's a hard freeze, RCU_CPU_STALL_TIMEOUT does not kick in.
>
> Tried other stable kernels, which all worked:
> 4.19.37
> 4.14.114
> 4.4.179
>
> So I suppose it's only a 4.9.x issue. Last working 4.9.x kernel I had in
> service was 4.9.161. First one I spotted freezing was 4.9.171. A bisect gave me
> the following commit:
>
> 1c38a84d45862be06ac418618981631eddbda741 is the first bad commit
> commit 1c38a84d45862be06ac418618981631eddbda741
> Author: Michael Neuling <mikey@neuling.org>
> Date: Thu Apr 11 21:45:59 2019 +1000
>
> powerpc: Avoid code patching freed init sections
>
> commit 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 upstream.
>
> This stops us from doing code patching in init sections after they've
> been freed.
>
> In this chain:
> kvm_guest_init() ->
> kvm_use_magic_page() ->
> fault_in_pages_readable() ->
> __get_user() ->
> __get_user_nocheck() ->
> barrier_nospec();
>
> We have a code patching location at barrier_nospec() and
> kvm_guest_init() is an init function. This whole chain gets inlined,
> so when we free the init section (hence kvm_guest_init()), this code
> goes away and hence should no longer be patched.
>
> We seen this as userspace memory corruption when using a memory
> checker while doing partition migration testing on powervm (this
> starts the code patching post migration via
> /sys/kernel/mobility/migration). In theory, it could also happen when
> using /sys/kernel/debug/powerpc/barrier_nospec.
>
> Cc: stable@vger.kernel.org # 4.13+
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
>
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Bug 203597] New: kernel 4.9.175 fails to boot on a PowerMac G4 3,6 at early stage
2019-05-14 4:56 ` [Bug 203597] New: kernel 4.9.175 fails to boot on a PowerMac G4 3,6 at early stage Christophe Leroy
@ 2019-05-14 7:05 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2019-05-14 7:05 UTC (permalink / raw)
To: Christophe Leroy; +Cc: linuxppc-dev, erhard_f, stable
On Tue, May 14, 2019 at 06:56:03AM +0200, Christophe Leroy wrote:
> Hi Greg,
>
> Could you please apply b45ba4a51cde29b2939365ef0c07ad34c8321789 to 4.9 since
> 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 was applied allthought marked for
> #4.13+
It does not apply there (nor to the 4.4.y queue, which will need it as
well), so can you provide a working backport so that I can queue it up?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2019-05-14 7:05 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <bug-203597-206035@https.bugzilla.kernel.org/>
2019-05-14 4:56 ` [Bug 203597] New: kernel 4.9.175 fails to boot on a PowerMac G4 3,6 at early stage Christophe Leroy
2019-05-14 7:05 ` Greg KH
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).