** Description changed:
[Impact]
Currently, we use the ACPI processor ID only for the leaf/processor nodes as
the specification states it must match the value of the ACPI processor ID field
in the processor’s entry in the MADT.
- However, if a PPTT structure represents a processors group, it matches a
processor container UID in the namespace and the
ACPI_PPTT_ACPI_PROCESSOR_ID_VALID flag indicates whether the ACPI processor ID
is valid.
-
- Let's use UID whenever ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is set to be
consistent instead of using table offset as it's currently done for non-leaf
nodes.
-
- Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table
parsing)
+ However, if a PPTT structure represents a processors group, it matches a
+ processor container UID in the namespace and the
+ ACPI_PPTT_ACPI_PROCESSOR_ID_VALID flag indicates whether the ACPI
+ processor ID is valid.
+ Let's use UID whenever ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is set to be
+ consistent instead of using table offset as it's currently done for non-
+ leaf nodes.
+
+ Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table
+ parsing)
[Fix]
This patch in is 4.18:
30998033f62a ACPI / PPTT: use ACPI ID whenever
ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is set
[Test]
+ -- testcase --
+ #!/bin/bash
+
+ stress-ng -q --vm 100 --vm-bytes 1G --cpu 210 --timeout 2400s --metrics-brief
&
+ pid=$!
+
+ for i in {1..210}; do
+ num=$((RANDOM%10+$i))
+ echo "Offline CPU $num"
+ echo 0 > /sys/devices/system/cpu/cpu$num/online || exit 1
+ sleep 3s
+ echo "Online CPU $num"
+ echo 1 > /sys/devices/system/cpu/cpu$num/online || exit 1
+ done
+
+ kill -9 $pid
+ ----------------
+ Executed the test case with stock Bionic kernel and with Bionic kernel with
patches applied. No system hang or crash was observed. On Cavium CN99XX Thunder
X2 system.
[Regression Potential]
+ Regression tested on Cavium Thunder X2 CN99XX system, and none were found.
Regression risk is low.
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https://bugs.launchpad.net/bugs/1797200
Title:
[Bionic] ACPI / PPTT: use ACPI ID whenever
ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is set
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