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author | Madhavan Srinivasan <maddy@linux.vnet.ibm.com> | 2017-11-02 17:42:26 +0530 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-11-03 09:38:05 +1100 |
commit | 7ecb37f62fe58e3e4d9b03443b92d213b2c108ce (patch) | |
tree | 87a0b315ded72ce270f2eab5ac0f846e6394f203 /arch/powerpc/perf/imc-pmu.c | |
parent | e6c4dcb308160115287afd87afb63b5684d75a5b (diff) | |
download | linux-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/powerpc/perf/imc-pmu.c')
-rw-r--r-- | arch/powerpc/perf/imc-pmu.c | 14 |
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); |