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    SubjectRe: [PATCH 4.18 00/79] 4.18.1-stable review
    On Wed, Aug 15, 2018 at 01:24:25PM -0400, Byron Stanoszek wrote:
    > Hi Greg & Thomas,
    >
    > I'd like to report a regression in Linux 4.18.1 regarding the L1TF patches.
    >
    > The kernel no longer thinks I have SMT enabled in the BIOS. This works fine in
    > 4.18.0.
    >
    > Not sure if this matters, but in my particular 4-core system, my third core is
    > broken (core #2). So I must boot using "maxcpus=2" and then online the other
    > cores & SMT threads at startup using:
    >
    > echo 1 > /sys/devices/system/cpu/cpu3/online
    > echo 1 > /sys/devices/system/cpu/cpu4/online
    > echo 1 > /sys/devices/system/cpu/cpu5/online
    > echo 1 > /sys/devices/system/cpu/cpu7/online
    >
    > In 4.18.0, dmesg shows:
    >
    > smpboot: Booting Node 0 Processor 3 APIC 0x6
    > smpboot: Booting Node 0 Processor 4 APIC 0x1
    > smpboot: Booting Node 0 Processor 5 APIC 0x3
    > smpboot: Booting Node 0 Processor 7 APIC 0x7
    >
    > In 4.18.1, dmesg shows:
    >
    > smpboot: Booting Node 0 Processor 3 APIC 0x6
    > smpboot: Booting Node 0 Processor 4 APIC 0x1
    > smpboot: CPU 4 is now offline
    > smpboot: Booting Node 0 Processor 5 APIC 0x3
    > smpboot: CPU 5 is now offline
    > smpboot: Booting Node 0 Processor 7 APIC 0x7
    > smpboot: CPU 7 is now offline
    >
    > and I get an "Operation cancelled" error in the shell when trying to online 4,
    > 5, and 7.
    >
    > In 4.18.1, /sys/devices/system/cpu/smt/control says "notsupported".
    >
    > - - -
    >
    > A possible second regression is the following:
    >
    > My CPU normally runs at 3600 MHz. I usually run my CPU at 2800 MHz to keep from
    > overheating under full load (it is a fanless system). I do this by running
    > "echo 1 > /sys/class/thermal/cooling_device5/cur_state", and confirm with "cat
    > /proc/cpuinfo" (shows 2800).
    >
    > This works in 4.18.0 but not in 4.18.1. I get no error from the "echo" command
    > (and the state reads back as "1"), but the CPU remains running at 3600 MHz.

    How about Linus's tree at the moment, is it ok there?

    thanks,

    greg k-h

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