Messages in this thread | | | From | Alexander Shishkin <> | Subject | Re: [PATCH] perf/x86/intel/bts: don't dereference ds unconditionally | Date | Tue, 20 Sep 2016 16:44:43 +0300 |
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Sebastian Andrzej Siewior <sebastian@breakpoint.cc> writes:
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > > Since commit 4d4c47412464 ("perf/x86/intel/bts: Fix BTS PMI detection") > my box goes boom on boot: > > | .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7 > | BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 > | IP: [<ffffffff8100c463>] intel_bts_interrupt+0x43/0x130 > | Call Trace: > | <NMI> d [<ffffffff8100b341>] intel_pmu_handle_irq+0x51/0x4b0 > | [<ffffffff81004d47>] perf_event_nmi_handler+0x27/0x40 > > I don't know what is going on here but ds is not always dereferenced > unconditionally hence here the `ds' check to avoid the crash.
Good catch! I'm going to guess you don't have the NMI watchdog enabled?
Thanks, -- Alex
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