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Groups > linux.kernel > #1532316
| From | Jiri Olsa <jolsa@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! |
| Date | 2016-11-29 15:10 +0100 |
| Message-ID | <sIRgB-12s-3@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <sFXVf-2nj-29@gated-at.bofh.it> <sFYRk-2Wx-37@gated-at.bofh.it> <sFZ10-2ZM-35@gated-at.bofh.it> <sFZkq-3oh-15@gated-at.bofh.it> <sIQDT-yf-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Nov 29, 2016 at 02:16:49PM +0100, Borislav Petkov wrote: > On Mon, Nov 21, 2016 at 05:06:54PM +0100, Borislav Petkov wrote: > > IOW, what's the worst thing that can happen if we did this below? > > > > We basically get rid of the detection and switch the timer to broadcast > > mode immediately on the halting CPU. > > > > amd_e400_idle() is behind an "if (cpu_has_bug(c, X86_BUG_AMD_APIC_C1E))" > > check so it will run on the affected CPUs only... > > > > Thoughts? > > Actually, here's a better version. The E400 detection works only after > ACPI has been enabled so we piggyback the end of acpi_init(). > > We don't need the MSR read now - we do > > if (static_cpu_has_bug(X86_BUG_AMD_APIC_C1E)) > > on the idle path which is as fast as it gets. > > Any complaints about this before I go and test it everywhere? > > It builds and boots in my guest here ok, not that it means a whole lot. > > The good news is, I have collected a fleet of boxes which all have that > erratum so testing should be pretty reliable. Something that doesn't > happen everytime! +1 one test server over here.. will check ;-) jirka
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Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Borislav Petkov <bp@alien8.de> - 2016-11-29 14:30 +0100
Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Jiri Olsa <jolsa@redhat.com> - 2016-11-29 15:10 +0100
Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Thomas Gleixner <tglx@linutronix.de> - 2016-11-29 15:10 +0100
Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Borislav Petkov <bp@alien8.de> - 2016-11-30 09:50 +0100
Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Thomas Gleixner <tglx@linutronix.de> - 2016-11-30 10:00 +0100
Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Borislav Petkov <bp@alien8.de> - 2016-11-30 10:10 +0100
Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Thomas Gleixner <tglx@linutronix.de> - 2016-11-30 10:20 +0100
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