<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/arch, branch linux-5.7.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()</title>
<updated>2020-08-27T07:30:50+00:00</updated>
<author>
<name>Michael Ellerman</name>
<email>mpe@ellerman.id.au</email>
</author>
<published>2020-05-27T14:58:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0bb568ce748783deb682a048664312e71fd30644'/>
<id>0bb568ce748783deb682a048664312e71fd30644</id>
<content type='text'>
commit 0828137e8f16721842468e33df0460044a0c588b upstream.

__init_FSCR() was added originally in commit 2468dcf641e4 ("powerpc:
Add support for context switching the TAR register") (Feb 2013), and
only set FSCR_TAR.

At that point FSCR (Facility Status and Control Register) was not
context switched, so the setting was permanent after boot.

Later we added initialisation of FSCR_DSCR to __init_FSCR(), in commit
54c9b2253d34 ("powerpc: Set DSCR bit in FSCR setup") (Mar 2013), again
that was permanent after boot.

Then commit 2517617e0de6 ("powerpc: Fix context switch DSCR on
POWER8") (Aug 2013) added a limited context switch of FSCR, just the
FSCR_DSCR bit was context switched based on thread.dscr_inherit. That
commit said "This clears the H/FSCR DSCR bit initially", but it
didn't, it left the initialisation of FSCR_DSCR in __init_FSCR().
However the initial context switch from init_task to pid 1 would clear
FSCR_DSCR because thread.dscr_inherit was 0.

That commit also introduced the requirement that FSCR_DSCR be clear
for user processes, so that we can take the facility unavailable
interrupt in order to manage dscr_inherit.

Then in commit 152d523e6307 ("powerpc: Create context switch helpers
save_sprs() and restore_sprs()") (Dec 2015) FSCR was added to
thread_struct. However it still wasn't fully context switched, we just
took the existing value and set FSCR_DSCR if the new thread had
dscr_inherit set. FSCR was still initialised at boot to FSCR_DSCR |
FSCR_TAR, but that value was not propagated into the thread_struct, so
the initial context switch set FSCR_DSCR back to 0.

Finally commit b57bd2de8c6c ("powerpc: Improve FSCR init and context
switching") (Jun 2016) added a full context switch of the FSCR, and
added an initialisation of init_task.thread.fscr to FSCR_TAR |
FSCR_EBB, but omitted FSCR_DSCR.

The end result is that swapper runs with FSCR_DSCR set because of the
initialisation in __init_FSCR(), but no other processes do, they use
the value from init_task.thread.fscr.

Having FSCR_DSCR set for swapper allows it to access SPR 3 from
userspace, but swapper never runs userspace, so it has no useful
effect. It's also confusing to have the value initialised in two
places to two different values.

So remove FSCR_DSCR from __init_FSCR(), this at least gets us to the
point where there's a single value of FSCR, even if it's still set in
two places.

Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Tested-by: Alistair Popple &lt;alistair@popple.id.au&gt;
Link: https://lore.kernel.org/r/20200527145843.2761782-1-mpe@ellerman.id.au
Cc: Thadeu Lima de Souza Cascardo &lt;cascardo@canonical.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0828137e8f16721842468e33df0460044a0c588b upstream.

__init_FSCR() was added originally in commit 2468dcf641e4 ("powerpc:
Add support for context switching the TAR register") (Feb 2013), and
only set FSCR_TAR.

At that point FSCR (Facility Status and Control Register) was not
context switched, so the setting was permanent after boot.

Later we added initialisation of FSCR_DSCR to __init_FSCR(), in commit
54c9b2253d34 ("powerpc: Set DSCR bit in FSCR setup") (Mar 2013), again
that was permanent after boot.

Then commit 2517617e0de6 ("powerpc: Fix context switch DSCR on
POWER8") (Aug 2013) added a limited context switch of FSCR, just the
FSCR_DSCR bit was context switched based on thread.dscr_inherit. That
commit said "This clears the H/FSCR DSCR bit initially", but it
didn't, it left the initialisation of FSCR_DSCR in __init_FSCR().
However the initial context switch from init_task to pid 1 would clear
FSCR_DSCR because thread.dscr_inherit was 0.

That commit also introduced the requirement that FSCR_DSCR be clear
for user processes, so that we can take the facility unavailable
interrupt in order to manage dscr_inherit.

Then in commit 152d523e6307 ("powerpc: Create context switch helpers
save_sprs() and restore_sprs()") (Dec 2015) FSCR was added to
thread_struct. However it still wasn't fully context switched, we just
took the existing value and set FSCR_DSCR if the new thread had
dscr_inherit set. FSCR was still initialised at boot to FSCR_DSCR |
FSCR_TAR, but that value was not propagated into the thread_struct, so
the initial context switch set FSCR_DSCR back to 0.

Finally commit b57bd2de8c6c ("powerpc: Improve FSCR init and context
switching") (Jun 2016) added a full context switch of the FSCR, and
added an initialisation of init_task.thread.fscr to FSCR_TAR |
FSCR_EBB, but omitted FSCR_DSCR.

The end result is that swapper runs with FSCR_DSCR set because of the
initialisation in __init_FSCR(), but no other processes do, they use
the value from init_task.thread.fscr.

Having FSCR_DSCR set for swapper allows it to access SPR 3 from
userspace, but swapper never runs userspace, so it has no useful
effect. It's also confusing to have the value initialised in two
places to two different values.

So remove FSCR_DSCR from __init_FSCR(), this at least gets us to the
point where there's a single value of FSCR, even if it's still set in
two places.

Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Tested-by: Alistair Popple &lt;alistair@popple.id.au&gt;
Link: https://lore.kernel.org/r/20200527145843.2761782-1-mpe@ellerman.id.au
Cc: Thadeu Lima de Souza Cascardo &lt;cascardo@canonical.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()</title>
<updated>2020-08-26T09:42:24+00:00</updated>
<author>
<name>Will Deacon</name>
<email>will@kernel.org</email>
</author>
<published>2020-08-11T10:27:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=89dd2cfd392be18a0b0fcbabf443a70c0d58b929'/>
<id>89dd2cfd392be18a0b0fcbabf443a70c0d58b929</id>
<content type='text'>
commit fdfe7cbd58806522e799e2a50a15aee7f2cbb7b6 upstream.

The 'flags' field of 'struct mmu_notifier_range' is used to indicate
whether invalidate_range_{start,end}() are permitted to block. In the
case of kvm_mmu_notifier_invalidate_range_start(), this field is not
forwarded on to the architecture-specific implementation of
kvm_unmap_hva_range() and therefore the backend cannot sensibly decide
whether or not to block.

Add an extra 'flags' parameter to kvm_unmap_hva_range() so that
architectures are aware as to whether or not they are permitted to block.

Cc: &lt;stable@vger.kernel.org&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Message-Id: &lt;20200811102725.7121-2-will@kernel.org&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fdfe7cbd58806522e799e2a50a15aee7f2cbb7b6 upstream.

The 'flags' field of 'struct mmu_notifier_range' is used to indicate
whether invalidate_range_{start,end}() are permitted to block. In the
case of kvm_mmu_notifier_invalidate_range_start(), this field is not
forwarded on to the architecture-specific implementation of
kvm_unmap_hva_range() and therefore the backend cannot sensibly decide
whether or not to block.

Add an extra 'flags' parameter to kvm_unmap_hva_range() so that
architectures are aware as to whether or not they are permitted to block.

Cc: &lt;stable@vger.kernel.org&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Cc: James Morse &lt;james.morse@arm.com&gt;
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Message-Id: &lt;20200811102725.7121-2-will@kernel.org&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>efi/x86: Mark kernel rodata non-executable for mixed mode</title>
<updated>2020-08-26T09:42:23+00:00</updated>
<author>
<name>Arvind Sankar</name>
<email>nivedita@alum.mit.edu</email>
</author>
<published>2020-07-17T19:45:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f2289422cfd90c5dac76f64bdd7ea831e75d4091'/>
<id>f2289422cfd90c5dac76f64bdd7ea831e75d4091</id>
<content type='text'>
commit c8502eb2d43b6b9b1dc382299a4d37031be63876 upstream.

When remapping the kernel rodata section RO in the EFI pagetables, the
protection flags that were used for the text section are being reused,
but the rodata section should not be marked executable.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200717194526.3452089-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c8502eb2d43b6b9b1dc382299a4d37031be63876 upstream.

When remapping the kernel rodata section RO in the EFI pagetables, the
protection flags that were used for the text section are being reused,
but the rodata section should not be marked executable.

Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Arvind Sankar &lt;nivedita@alum.mit.edu&gt;
Link: https://lore.kernel.org/r/20200717194526.3452089-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/pseries: Do not initiate shutdown when system is running on UPS</title>
<updated>2020-08-26T09:42:23+00:00</updated>
<author>
<name>Vasant Hegde</name>
<email>hegdevasant@linux.vnet.ibm.com</email>
</author>
<published>2020-08-20T06:18:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c6e7867105f9aedf6017631084b52bc75cae4351'/>
<id>c6e7867105f9aedf6017631084b52bc75cae4351</id>
<content type='text'>
commit 90a9b102eddf6a3f987d15f4454e26a2532c1c98 upstream.

As per PAPR we have to look for both EPOW sensor value and event
modifier to identify the type of event and take appropriate action.

In LoPAPR v1.1 section 10.2.2 includes table 136 "EPOW Action Codes":

  SYSTEM_SHUTDOWN 3

  The system must be shut down. An EPOW-aware OS logs the EPOW error
  log information, then schedules the system to be shut down to begin
  after an OS defined delay internal (default is 10 minutes.)

Then in section 10.3.2.2.8 there is table 146 "Platform Event Log
Format, Version 6, EPOW Section", which includes the "EPOW Event
Modifier":

  For EPOW sensor value = 3
  0x01 = Normal system shutdown with no additional delay
  0x02 = Loss of utility power, system is running on UPS/Battery
  0x03 = Loss of system critical functions, system should be shutdown
  0x04 = Ambient temperature too high
  All other values = reserved

We have a user space tool (rtas_errd) on LPAR to monitor for
EPOW_SHUTDOWN_ON_UPS. Once it gets an event it initiates shutdown
after predefined time. It also starts monitoring for any new EPOW
events. If it receives "Power restored" event before predefined time
it will cancel the shutdown. Otherwise after predefined time it will
shutdown the system.

Commit 79872e35469b ("powerpc/pseries: All events of
EPOW_SYSTEM_SHUTDOWN must initiate shutdown") changed our handling of
the "on UPS/Battery" case, to immediately shutdown the system. This
breaks existing setups that rely on the userspace tool to delay
shutdown and let the system run on the UPS.

Fixes: 79872e35469b ("powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Vasant Hegde &lt;hegdevasant@linux.vnet.ibm.com&gt;
[mpe: Massage change log and add PAPR references]
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20200820061844.306460-1-hegdevasant@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 90a9b102eddf6a3f987d15f4454e26a2532c1c98 upstream.

As per PAPR we have to look for both EPOW sensor value and event
modifier to identify the type of event and take appropriate action.

In LoPAPR v1.1 section 10.2.2 includes table 136 "EPOW Action Codes":

  SYSTEM_SHUTDOWN 3

  The system must be shut down. An EPOW-aware OS logs the EPOW error
  log information, then schedules the system to be shut down to begin
  after an OS defined delay internal (default is 10 minutes.)

Then in section 10.3.2.2.8 there is table 146 "Platform Event Log
Format, Version 6, EPOW Section", which includes the "EPOW Event
Modifier":

  For EPOW sensor value = 3
  0x01 = Normal system shutdown with no additional delay
  0x02 = Loss of utility power, system is running on UPS/Battery
  0x03 = Loss of system critical functions, system should be shutdown
  0x04 = Ambient temperature too high
  All other values = reserved

We have a user space tool (rtas_errd) on LPAR to monitor for
EPOW_SHUTDOWN_ON_UPS. Once it gets an event it initiates shutdown
after predefined time. It also starts monitoring for any new EPOW
events. If it receives "Power restored" event before predefined time
it will cancel the shutdown. Otherwise after predefined time it will
shutdown the system.

Commit 79872e35469b ("powerpc/pseries: All events of
EPOW_SYSTEM_SHUTDOWN must initiate shutdown") changed our handling of
the "on UPS/Battery" case, to immediately shutdown the system. This
breaks existing setups that rely on the userspace tool to delay
shutdown and let the system run on the UPS.

Fixes: 79872e35469b ("powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Vasant Hegde &lt;hegdevasant@linux.vnet.ibm.com&gt;
[mpe: Massage change log and add PAPR references]
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20200820061844.306460-1-hegdevasant@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/pseries/hotplug-cpu: wait indefinitely for vCPU death</title>
<updated>2020-08-26T09:42:22+00:00</updated>
<author>
<name>Michael Roth</name>
<email>mdroth@linux.vnet.ibm.com</email>
</author>
<published>2020-08-11T16:15:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=70da6a4fddc2779f143db9c4affd0fb328d2f716'/>
<id>70da6a4fddc2779f143db9c4affd0fb328d2f716</id>
<content type='text'>
[ Upstream commit 801980f6497946048709b9b09771a1729551d705 ]

For a power9 KVM guest with XIVE enabled, running a test loop
where we hotplug 384 vcpus and then unplug them, the following traces
can be seen (generally within a few loops) either from the unplugged
vcpu:

  cpu 65 (hwid 65) Ready to die...
  Querying DEAD? cpu 66 (66) shows 2
  list_del corruption. next-&gt;prev should be c00a000002470208, but was c00a000002470048
  ------------[ cut here ]------------
  kernel BUG at lib/list_debug.c:56!
  Oops: Exception in kernel mode, sig: 5 [#1]
  LE SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: fuse nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 ...
  CPU: 66 PID: 0 Comm: swapper/66 Kdump: loaded Not tainted 4.18.0-221.el8.ppc64le #1
  NIP:  c0000000007ab50c LR: c0000000007ab508 CTR: 00000000000003ac
  REGS: c0000009e5a17840 TRAP: 0700   Not tainted  (4.18.0-221.el8.ppc64le)
  MSR:  800000000282b033 &lt;SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE&gt;  CR: 28000842  XER: 20040000
  ...
  NIP __list_del_entry_valid+0xac/0x100
  LR  __list_del_entry_valid+0xa8/0x100
  Call Trace:
    __list_del_entry_valid+0xa8/0x100 (unreliable)
    free_pcppages_bulk+0x1f8/0x940
    free_unref_page+0xd0/0x100
    xive_spapr_cleanup_queue+0x148/0x1b0
    xive_teardown_cpu+0x1bc/0x240
    pseries_mach_cpu_die+0x78/0x2f0
    cpu_die+0x48/0x70
    arch_cpu_idle_dead+0x20/0x40
    do_idle+0x2f4/0x4c0
    cpu_startup_entry+0x38/0x40
    start_secondary+0x7bc/0x8f0
    start_secondary_prolog+0x10/0x14

or on the worker thread handling the unplug:

  pseries-hotplug-cpu: Attempting to remove CPU &lt;NULL&gt;, drc index: 1000013a
  Querying DEAD? cpu 314 (314) shows 2
  BUG: Bad page state in process kworker/u768:3  pfn:95de1
  cpu 314 (hwid 314) Ready to die...
  page:c00a000002577840 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0
  flags: 0x5ffffc00000000()
  raw: 005ffffc00000000 5deadbeef0000100 5deadbeef0000200 0000000000000000
  raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
  page dumped because: nonzero mapcount
  Modules linked in: kvm xt_CHECKSUM ipt_MASQUERADE xt_conntrack ...
  CPU: 0 PID: 548 Comm: kworker/u768:3 Kdump: loaded Not tainted 4.18.0-224.el8.bz1856588.ppc64le #1
  Workqueue: pseries hotplug workque pseries_hp_work_fn
  Call Trace:
    dump_stack+0xb0/0xf4 (unreliable)
    bad_page+0x12c/0x1b0
    free_pcppages_bulk+0x5bc/0x940
    page_alloc_cpu_dead+0x118/0x120
    cpuhp_invoke_callback.constprop.5+0xb8/0x760
    _cpu_down+0x188/0x340
    cpu_down+0x5c/0xa0
    cpu_subsys_offline+0x24/0x40
    device_offline+0xf0/0x130
    dlpar_offline_cpu+0x1c4/0x2a0
    dlpar_cpu_remove+0xb8/0x190
    dlpar_cpu_remove_by_index+0x12c/0x150
    dlpar_cpu+0x94/0x800
    pseries_hp_work_fn+0x128/0x1e0
    process_one_work+0x304/0x5d0
    worker_thread+0xcc/0x7a0
    kthread+0x1ac/0x1c0
    ret_from_kernel_thread+0x5c/0x80

The latter trace is due to the following sequence:

  page_alloc_cpu_dead
    drain_pages
      drain_pages_zone
        free_pcppages_bulk

where drain_pages() in this case is called under the assumption that
the unplugged cpu is no longer executing. To ensure that is the case,
and early call is made to __cpu_die()-&gt;pseries_cpu_die(), which runs a
loop that waits for the cpu to reach a halted state by polling its
status via query-cpu-stopped-state RTAS calls. It only polls for 25
iterations before giving up, however, and in the trace above this
results in the following being printed only .1 seconds after the
hotplug worker thread begins processing the unplug request:

  pseries-hotplug-cpu: Attempting to remove CPU &lt;NULL&gt;, drc index: 1000013a
  Querying DEAD? cpu 314 (314) shows 2

At that point the worker thread assumes the unplugged CPU is in some
unknown/dead state and procedes with the cleanup, causing the race
with the XIVE cleanup code executed by the unplugged CPU.

Fix this by waiting indefinitely, but also making an effort to avoid
spurious lockup messages by allowing for rescheduling after polling
the CPU status and printing a warning if we wait for longer than 120s.

Fixes: eac1e731b59ee ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
Suggested-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Signed-off-by: Michael Roth &lt;mdroth@linux.vnet.ibm.com&gt;
Tested-by: Greg Kurz &lt;groug@kaod.org&gt;
Reviewed-by: Thiago Jung Bauermann &lt;bauerman@linux.ibm.com&gt;
Reviewed-by: Greg Kurz &lt;groug@kaod.org&gt;
[mpe: Trim oopses in change log slightly for readability]
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20200811161544.10513-1-mdroth@linux.vnet.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 801980f6497946048709b9b09771a1729551d705 ]

For a power9 KVM guest with XIVE enabled, running a test loop
where we hotplug 384 vcpus and then unplug them, the following traces
can be seen (generally within a few loops) either from the unplugged
vcpu:

  cpu 65 (hwid 65) Ready to die...
  Querying DEAD? cpu 66 (66) shows 2
  list_del corruption. next-&gt;prev should be c00a000002470208, but was c00a000002470048
  ------------[ cut here ]------------
  kernel BUG at lib/list_debug.c:56!
  Oops: Exception in kernel mode, sig: 5 [#1]
  LE SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: fuse nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 ...
  CPU: 66 PID: 0 Comm: swapper/66 Kdump: loaded Not tainted 4.18.0-221.el8.ppc64le #1
  NIP:  c0000000007ab50c LR: c0000000007ab508 CTR: 00000000000003ac
  REGS: c0000009e5a17840 TRAP: 0700   Not tainted  (4.18.0-221.el8.ppc64le)
  MSR:  800000000282b033 &lt;SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE&gt;  CR: 28000842  XER: 20040000
  ...
  NIP __list_del_entry_valid+0xac/0x100
  LR  __list_del_entry_valid+0xa8/0x100
  Call Trace:
    __list_del_entry_valid+0xa8/0x100 (unreliable)
    free_pcppages_bulk+0x1f8/0x940
    free_unref_page+0xd0/0x100
    xive_spapr_cleanup_queue+0x148/0x1b0
    xive_teardown_cpu+0x1bc/0x240
    pseries_mach_cpu_die+0x78/0x2f0
    cpu_die+0x48/0x70
    arch_cpu_idle_dead+0x20/0x40
    do_idle+0x2f4/0x4c0
    cpu_startup_entry+0x38/0x40
    start_secondary+0x7bc/0x8f0
    start_secondary_prolog+0x10/0x14

or on the worker thread handling the unplug:

  pseries-hotplug-cpu: Attempting to remove CPU &lt;NULL&gt;, drc index: 1000013a
  Querying DEAD? cpu 314 (314) shows 2
  BUG: Bad page state in process kworker/u768:3  pfn:95de1
  cpu 314 (hwid 314) Ready to die...
  page:c00a000002577840 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0
  flags: 0x5ffffc00000000()
  raw: 005ffffc00000000 5deadbeef0000100 5deadbeef0000200 0000000000000000
  raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
  page dumped because: nonzero mapcount
  Modules linked in: kvm xt_CHECKSUM ipt_MASQUERADE xt_conntrack ...
  CPU: 0 PID: 548 Comm: kworker/u768:3 Kdump: loaded Not tainted 4.18.0-224.el8.bz1856588.ppc64le #1
  Workqueue: pseries hotplug workque pseries_hp_work_fn
  Call Trace:
    dump_stack+0xb0/0xf4 (unreliable)
    bad_page+0x12c/0x1b0
    free_pcppages_bulk+0x5bc/0x940
    page_alloc_cpu_dead+0x118/0x120
    cpuhp_invoke_callback.constprop.5+0xb8/0x760
    _cpu_down+0x188/0x340
    cpu_down+0x5c/0xa0
    cpu_subsys_offline+0x24/0x40
    device_offline+0xf0/0x130
    dlpar_offline_cpu+0x1c4/0x2a0
    dlpar_cpu_remove+0xb8/0x190
    dlpar_cpu_remove_by_index+0x12c/0x150
    dlpar_cpu+0x94/0x800
    pseries_hp_work_fn+0x128/0x1e0
    process_one_work+0x304/0x5d0
    worker_thread+0xcc/0x7a0
    kthread+0x1ac/0x1c0
    ret_from_kernel_thread+0x5c/0x80

The latter trace is due to the following sequence:

  page_alloc_cpu_dead
    drain_pages
      drain_pages_zone
        free_pcppages_bulk

where drain_pages() in this case is called under the assumption that
the unplugged cpu is no longer executing. To ensure that is the case,
and early call is made to __cpu_die()-&gt;pseries_cpu_die(), which runs a
loop that waits for the cpu to reach a halted state by polling its
status via query-cpu-stopped-state RTAS calls. It only polls for 25
iterations before giving up, however, and in the trace above this
results in the following being printed only .1 seconds after the
hotplug worker thread begins processing the unplug request:

  pseries-hotplug-cpu: Attempting to remove CPU &lt;NULL&gt;, drc index: 1000013a
  Querying DEAD? cpu 314 (314) shows 2

At that point the worker thread assumes the unplugged CPU is in some
unknown/dead state and procedes with the cleanup, causing the race
with the XIVE cleanup code executed by the unplugged CPU.

Fix this by waiting indefinitely, but also making an effort to avoid
spurious lockup messages by allowing for rescheduling after polling
the CPU status and printing a warning if we wait for longer than 120s.

Fixes: eac1e731b59ee ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
Suggested-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Signed-off-by: Michael Roth &lt;mdroth@linux.vnet.ibm.com&gt;
Tested-by: Greg Kurz &lt;groug@kaod.org&gt;
Reviewed-by: Thiago Jung Bauermann &lt;bauerman@linux.ibm.com&gt;
Reviewed-by: Greg Kurz &lt;groug@kaod.org&gt;
[mpe: Trim oopses in change log slightly for readability]
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/20200811161544.10513-1-mdroth@linux.vnet.ibm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/fixmap: Fix the size of the early debug area</title>
<updated>2020-08-26T09:42:22+00:00</updated>
<author>
<name>Christophe Leroy</name>
<email>christophe.leroy@csgroup.eu</email>
</author>
<published>2020-08-17T06:03:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1622360234fb636d2a8bfaea0778a7ccf0a3eeae'/>
<id>1622360234fb636d2a8bfaea0778a7ccf0a3eeae</id>
<content type='text'>
[ Upstream commit fdc6edbb31fba76fd25d7bd016b675a92908d81e ]

Commit ("03fd42d458fb powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when
page size is 256k") reworked the setup of the early debug area and
mistakenly replaced 128 * 1024 by SZ_128.

Change to SZ_128K to restore the original 128 kbytes size of the area.

Fixes: 03fd42d458fb ("powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when page size is 256k")
Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/996184974d674ff984643778cf1cdd7fe58cc065.1597644194.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit fdc6edbb31fba76fd25d7bd016b675a92908d81e ]

Commit ("03fd42d458fb powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when
page size is 256k") reworked the setup of the early debug area and
mistakenly replaced 128 * 1024 by SZ_128.

Change to SZ_128K to restore the original 128 kbytes size of the area.

Fixes: 03fd42d458fb ("powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when page size is 256k")
Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/996184974d674ff984643778cf1cdd7fe58cc065.1597644194.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ARM64: vdso32: Install vdso32 from vdso_install</title>
<updated>2020-08-26T09:42:22+00:00</updated>
<author>
<name>Stephen Boyd</name>
<email>swboyd@chromium.org</email>
</author>
<published>2020-08-18T01:49:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2ac6c08a4ed5960fcad7392a2c27fdc4427f7f41'/>
<id>2ac6c08a4ed5960fcad7392a2c27fdc4427f7f41</id>
<content type='text'>
[ Upstream commit 8d75785a814241587802655cc33e384230744f0c ]

Add the 32-bit vdso Makefile to the vdso_install rule so that 'make
vdso_install' installs the 32-bit compat vdso when it is compiled.

Fixes: a7f71a2c8903 ("arm64: compat: Add vDSO")
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Reviewed-by: Vincenzo Frascino &lt;vincenzo.frascino@arm.com&gt;
Acked-by: Will Deacon &lt;will@kernel.org&gt;
Cc: Vincenzo Frascino &lt;vincenzo.frascino@arm.com&gt;
Link: https://lore.kernel.org/r/20200818014950.42492-1-swboyd@chromium.org
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 8d75785a814241587802655cc33e384230744f0c ]

Add the 32-bit vdso Makefile to the vdso_install rule so that 'make
vdso_install' installs the 32-bit compat vdso when it is compiled.

Fixes: a7f71a2c8903 ("arm64: compat: Add vDSO")
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Reviewed-by: Vincenzo Frascino &lt;vincenzo.frascino@arm.com&gt;
Acked-by: Will Deacon &lt;will@kernel.org&gt;
Cc: Vincenzo Frascino &lt;vincenzo.frascino@arm.com&gt;
Link: https://lore.kernel.org/r/20200818014950.42492-1-swboyd@chromium.org
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Fix build error when CONFIG_ACPI is not set/enabled:</title>
<updated>2020-08-26T09:42:21+00:00</updated>
<author>
<name>Randy Dunlap</name>
<email>rdunlap@infradead.org</email>
</author>
<published>2020-08-20T04:30:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cdd79a94d7de05ed619720b982080a20aad7479e'/>
<id>cdd79a94d7de05ed619720b982080a20aad7479e</id>
<content type='text'>
[ Upstream commit ee87e1557c42dc9c2da11c38e11b87c311569853 ]

../arch/x86/pci/xen.c: In function ‘pci_xen_init’:
../arch/x86/pci/xen.c:410:2: error: implicit declaration of function ‘acpi_noirq_set’; did you mean ‘acpi_irq_get’? [-Werror=implicit-function-declaration]
  acpi_noirq_set();

Fixes: 88e9ca161c13 ("xen/pci: Use acpi_noirq_set() helper to avoid #ifdef")
Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: Konrad Rzeszutek Wilk &lt;konrad.wilk@oracle.com&gt;
Cc: xen-devel@lists.xenproject.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit ee87e1557c42dc9c2da11c38e11b87c311569853 ]

../arch/x86/pci/xen.c: In function ‘pci_xen_init’:
../arch/x86/pci/xen.c:410:2: error: implicit declaration of function ‘acpi_noirq_set’; did you mean ‘acpi_irq_get’? [-Werror=implicit-function-declaration]
  acpi_noirq_set();

Fixes: 88e9ca161c13 ("xen/pci: Use acpi_noirq_set() helper to avoid #ifdef")
Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Cc: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Cc: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: Konrad Rzeszutek Wilk &lt;konrad.wilk@oracle.com&gt;
Cc: xen-devel@lists.xenproject.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kvm: x86: Toggling CR4.PKE does not load PDPTEs in PAE mode</title>
<updated>2020-08-26T09:42:19+00:00</updated>
<author>
<name>Jim Mattson</name>
<email>jmattson@google.com</email>
</author>
<published>2020-08-17T18:16:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3ce5771abb96c64d55e8480425a4707f2df8d863'/>
<id>3ce5771abb96c64d55e8480425a4707f2df8d863</id>
<content type='text'>
[ Upstream commit cb957adb4ea422bd758568df5b2478ea3bb34f35 ]

See the SDM, volume 3, section 4.4.1:

If PAE paging would be in use following an execution of MOV to CR0 or
MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of
CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then
the PDPTEs are loaded from the address in CR3.

Fixes: b9baba8614890 ("KVM, pkeys: expose CPUID/CR4 to guest")
Cc: Huaitong Han &lt;huaitong.han@intel.com&gt;
Signed-off-by: Jim Mattson &lt;jmattson@google.com&gt;
Reviewed-by: Peter Shier &lt;pshier@google.com&gt;
Reviewed-by: Oliver Upton &lt;oupton@google.com&gt;
Message-Id: &lt;20200817181655.3716509-1-jmattson@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit cb957adb4ea422bd758568df5b2478ea3bb34f35 ]

See the SDM, volume 3, section 4.4.1:

If PAE paging would be in use following an execution of MOV to CR0 or
MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of
CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then
the PDPTEs are loaded from the address in CR3.

Fixes: b9baba8614890 ("KVM, pkeys: expose CPUID/CR4 to guest")
Cc: Huaitong Han &lt;huaitong.han@intel.com&gt;
Signed-off-by: Jim Mattson &lt;jmattson@google.com&gt;
Reviewed-by: Peter Shier &lt;pshier@google.com&gt;
Reviewed-by: Oliver Upton &lt;oupton@google.com&gt;
Message-Id: &lt;20200817181655.3716509-1-jmattson@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode</title>
<updated>2020-08-26T09:42:19+00:00</updated>
<author>
<name>Jim Mattson</name>
<email>jmattson@google.com</email>
</author>
<published>2020-08-17T18:16:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=374c3b5a7775c0dad89a8f7be1515d7c9cda514b'/>
<id>374c3b5a7775c0dad89a8f7be1515d7c9cda514b</id>
<content type='text'>
[ Upstream commit 427890aff8558eb4326e723835e0eae0e6fe3102 ]

See the SDM, volume 3, section 4.4.1:

If PAE paging would be in use following an execution of MOV to CR0 or
MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of
CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then
the PDPTEs are loaded from the address in CR3.

Fixes: 0be0226f07d14 ("KVM: MMU: fix SMAP virtualization")
Cc: Xiao Guangrong &lt;guangrong.xiao@linux.intel.com&gt;
Signed-off-by: Jim Mattson &lt;jmattson@google.com&gt;
Reviewed-by: Peter Shier &lt;pshier@google.com&gt;
Reviewed-by: Oliver Upton &lt;oupton@google.com&gt;
Message-Id: &lt;20200817181655.3716509-2-jmattson@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 427890aff8558eb4326e723835e0eae0e6fe3102 ]

See the SDM, volume 3, section 4.4.1:

If PAE paging would be in use following an execution of MOV to CR0 or
MOV to CR4 (see Section 4.1.1) and the instruction is modifying any of
CR0.CD, CR0.NW, CR0.PG, CR4.PAE, CR4.PGE, CR4.PSE, or CR4.SMEP; then
the PDPTEs are loaded from the address in CR3.

Fixes: 0be0226f07d14 ("KVM: MMU: fix SMAP virtualization")
Cc: Xiao Guangrong &lt;guangrong.xiao@linux.intel.com&gt;
Signed-off-by: Jim Mattson &lt;jmattson@google.com&gt;
Reviewed-by: Peter Shier &lt;pshier@google.com&gt;
Reviewed-by: Oliver Upton &lt;oupton@google.com&gt;
Message-Id: &lt;20200817181655.3716509-2-jmattson@google.com&gt;
Signed-off-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
