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authorAnju T Sudhakar <anju@linux.vnet.ibm.com>2017-12-05 11:00:38 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2017-12-13 20:36:53 +1100
commitad2b6e01024ef23bddc3ce0bcb115ecd8c520b7e (patch)
tree56a6e27a464240df94eb682159d88f5756019a02 /arch/powerpc/perf
parentf41d84dddc66b164ac16acf3f584c276146f1c48 (diff)
powerpc/perf/imc: Fix nest-imc cpuhotplug callback failure
Oops is observed during boot: Faulting instruction address: 0xc000000000248340 cpu 0x0: Vector: 380 (Data Access Out of Range) at [c000000ff66fb850] pc: c000000000248340: event_function_call+0x50/0x1f0 lr: c00000000024878c: perf_remove_from_context+0x3c/0x100 sp: c000000ff66fbad0 msr: 9000000000009033 dar: 7d20e2a6f92d03c0 pid = 14, comm = cpuhp/0 While registering the cpuhotplug callbacks for nest-imc, if we fail in the cpuhotplug online path for any random node in a multi node system (because the opal call to stop nest-imc counters fails for that node), ppc_nest_imc_cpu_offline() will get invoked for other nodes who successfully returned from cpuhotplug online path. This call trace is generated since in the ppc_nest_imc_cpu_offline() path we are trying to migrate the event context, when nest-imc counters are not even initialized. Patch to add a check to ensure that nest-imc is registered before migrating the event context. Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support") Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/perf')
-rw-r--r--arch/powerpc/perf/imc-pmu.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 0ead3cd73caa..f1b940714d65 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -310,6 +310,19 @@ static int ppc_nest_imc_cpu_offline(unsigned int cpu)
return 0;
/*
+ * Check whether nest_imc is registered. We could end up here if the
+ * cpuhotplug callback registration fails. i.e, callback invokes the
+ * offline path for all successfully registered nodes. At this stage,
+ * nest_imc pmu will not be registered and we should return here.
+ *
+ * We return with a zero since this is not an offline failure. And
+ * cpuhp_setup_state() returns the actual failure reason to the caller,
+ * which in turn will call the cleanup routine.
+ */
+ if (!nest_pmus)
+ return 0;
+
+ /*
* Now that this cpu is one of the designated,
* find a next cpu a) which is online and b) in same chip.
*/