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authorMadhavan Srinivasan <maddy@linux.vnet.ibm.com>2017-11-02 17:42:26 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2017-11-03 09:38:05 +1100
commit7ecb37f62fe58e3e4d9b03443b92d213b2c108ce (patch)
tree87a0b315ded72ce270f2eab5ac0f846e6394f203 /arch
parente6c4dcb308160115287afd87afb63b5684d75a5b (diff)
downloadlinux-7ecb37f62fe58e3e4d9b03443b92d213b2c108ce.tar.bz2
powerpc/perf: Fix core-imc hotplug callback failure during imc initialization
Call trace observed during boot: nest_capp0_imc performance monitor hardware support registered nest_capp1_imc performance monitor hardware support registered core_imc memory allocation for cpu 56 failed Unable to handle kernel paging request for data at address 0xffa400010 Faulting instruction address: 0xc000000000bf3294 0:mon> e cpu 0x0: Vector: 300 (Data Access) at [c000000ff38ff8d0] pc: c000000000bf3294: mutex_lock+0x34/0x90 lr: c000000000bf3288: mutex_lock+0x28/0x90 sp: c000000ff38ffb50 msr: 9000000002009033 dar: ffa400010 dsisr: 80000 current = 0xc000000ff383de00 paca = 0xc000000007ae0000 softe: 0 irq_happened: 0x01 pid = 13, comm = cpuhp/0 Linux version 4.11.0-39.el7a.ppc64le (mockbuild@ppc-058.build.eng.bos.redhat.com) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-16) (GCC) ) #1 SMP Tue Oct 3 07:42:44 EDT 2017 0:mon> t [c000000ff38ffb80] c0000000002ddfac perf_pmu_migrate_context+0xac/0x470 [c000000ff38ffc40] c00000000011385c ppc_core_imc_cpu_offline+0x1ac/0x1e0 [c000000ff38ffc90] c000000000125758 cpuhp_invoke_callback+0x198/0x5d0 [c000000ff38ffd00] c00000000012782c cpuhp_thread_fun+0x8c/0x3d0 [c000000ff38ffd60] c0000000001678d0 smpboot_thread_fn+0x290/0x2a0 [c000000ff38ffdc0] c00000000015ee78 kthread+0x168/0x1b0 [c000000ff38ffe30] c00000000000b368 ret_from_kernel_thread+0x5c/0x74 While registering the cpuhoplug callbacks for core-imc, if we fails in the cpuhotplug online path for any random core (either because opal call to initialize the core-imc counters fails or because memory allocation fails for that core), ppc_core_imc_cpu_offline() will get invoked for other cpus who successfully returned from cpuhotplug online path. But in the ppc_core_imc_cpu_offline() path we are trying to migrate the event context, when core-imc counters are not even initialized. Thus creating the above stack dump. Add a check to see if core-imc counters are enabled or not in the cpuhotplug offline path before migrating the context to handle this failing scenario. Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support") Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/perf/imc-pmu.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 92ae5de0bbac..36344117c680 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -607,6 +607,20 @@ static int ppc_core_imc_cpu_offline(unsigned int cpu)
if (!cpumask_test_and_clear_cpu(cpu, &core_imc_cpumask))
return 0;
+ /*
+ * Check whether core_imc is registered. We could end up here
+ * if the cpuhotplug callback registration fails. i.e, callback
+ * invokes the offline path for all sucessfully registered cpus.
+ * At this stage, core_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 inturn will call the cleanup routine.
+ */
+ if (!core_imc_pmu->pmu.event_init)
+ return 0;
+
/* Find any online cpu in that core except the current "cpu" */
ncpu = cpumask_any_but(cpu_sibling_mask(cpu), cpu);