<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - [CI][DRMTIP] igt@perf_pmu@cpu-hotplug - timeout/dmesg-fail - WARNING: Failed to online cpu" href="https://bugs.freedesktop.org/show_bug.cgi?id=111561#c7">Comment # 7</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - [CI][DRMTIP] igt@perf_pmu@cpu-hotplug - timeout/dmesg-fail - WARNING: Failed to online cpu" href="https://bugs.freedesktop.org/show_bug.cgi?id=111561">bug 111561</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>Third attempt gave, 558682b5291937a70748d36fd9ba757fb25b99ae is the first bad commit commit 558682b5291937a70748d36fd9ba757fb25b99ae Author: Bandan Das <<a href="mailto:bsd@redhat.com">bsd@redhat.com</a>> Date: Mon Aug 26 06:15:13 2019 -0400 x86/apic: Include the LDR when clearing out APIC registers Although APIC initialization will typically clear out the LDR before setting it, the APIC cleanup code should reset the LDR. This was discovered with a 32-bit KVM guest jumping into a kdump kernel. The stale bits in the LDR triggered a bug in the KVM APIC implementation which caused the destination mapping for VCPUs to be corrupted. Note that this isn't intended to paper over the KVM APIC bug. The kernel has to clear the LDR when resetting the APIC registers except when X2APIC is enabled. This lacks a Fixes tag because missing to clear LDR goes way back into pre git history. [ tglx: Made x2apic_enabled a function call as required ] Signed-off-by: Bandan Das <<a href="mailto:bsd@redhat.com">bsd@redhat.com</a>> Signed-off-by: Thomas Gleixner <<a href="mailto:tglx@linutronix.de">tglx@linutronix.de</a>> Cc: <a href="mailto:stable@vger.kernel.org">stable@vger.kernel.org</a> Link: <a href="https://lkml.kernel.org/r/20190826101513.5080-3-bsd@redhat.com">https://lkml.kernel.org/r/20190826101513.5080-3-bsd@redhat.com</a> :040000 040000 f523ff2c03fab6308dad45a102e0fd3313a00475 76d836afd63b7f540a124e763456c233d07c7061 M arch</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>