| Message ID | 1509624746-5632-1-git-send-email-anju@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 7ecb37f62fe58e3e4d9b03443b92d213b2c108ce |
| Headers | show |
| Series | [v2] powerpc/perf: Fix core-imc hotplug callback failure during imc initialization | expand |
On Thu, 2017-11-02 at 12:12:26 UTC, Anju T Sudhakar wrote: > From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> > > Call trace observed during boot: > > [ 0.750749] PCI: CLS 0 bytes, default 128 > [ 0.750855] Unpacking initramfs... > [ 1.570445] Freeing initrd memory: 23168K > [ 1.571090] rtas_flash: no firmware flash support > [ 1.573873] nest_capp0_imc performance monitor hardware support registered > [ 1.574006] nest_capp1_imc performance monitor hardware support registered > [ 1.579616] core_imc memory allocation for cpu 56 failed > [ 1.579730] Unable to handle kernel paging request for data at address 0xffa400010 > [ 1.579797] 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. > > Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> > Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/7ecb37f62fe58e3e4d9b03443b92d2 cheers
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c index 8812624..a7a1db4 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);