From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Cc: maddy@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org,
anju@linux.vnet.ibm.com, linux-kernel@vger.kernel.org
Subject: Re: powerpc/perf: Fix nest-imc cpuhotplug callback failure
Date: Fri, 22 Dec 2017 15:43:21 +1100 (AEDT) [thread overview]
Message-ID: <3z2wqs6MWtz9s7B@ozlabs.org> (raw)
In-Reply-To: <1512451838-10456-1-git-send-email-anju@linux.vnet.ibm.com>
On Tue, 2017-12-05 at 05:30:38 UTC, Anju T Sudhakar wrote:
> Call trace 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
> current = 0xc000000ff6679200
> paca = 0xc00000000fd40000 softe: 0 irq_happened: 0x01
> pid = 14, comm = cpuhp/0
> Linux version 4.14.0-rc2-42789-ge8eae4b (rgrimm@XXXX) (gcc version 5.4.0
> 20160609 (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.4)) #1 SMP Thu Nov 16 14:35:14 CST
> 2017
> enter ? for help
> [c000000ff66fbb80] c00000000024878c perf_remove_from_context+0x3c/0x100
> [c000000ff66fbbc0] c00000000024e84c perf_pmu_migrate_context+0x10c/0x380
> [c000000ff66fbc60] c0000000000ca050 ppc_nest_imc_cpu_offline+0x1b0/0x210
> [c000000ff66fbcb0] c0000000000d5d54 cpuhp_invoke_callback+0x194/0x620
> [c000000ff66fbd20] c0000000000d702c cpuhp_thread_fun+0x7c/0x1b0
> [c000000ff66fbd60] c00000000010ad90 smpboot_thread_fn+0x290/0x2a0
> [c000000ff66fbdc0] c000000000104818 kthread+0x168/0x1b0
> [c000000ff66fbe30] c00000000000b5a0 ret_from_kernel_thread+0x5c/0xbc
>
> 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.
>
> Note:
> Madhavan Srinivasan has recently send a skiboot patch to have a check in the
> skiboot code to make sure that the microcode is initialized in all the chips,
> before enabling the nest units.
> https://patchwork.ozlabs.org/patch/844047/ (v2)
>
> Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
> Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/ad2b6e01024ef23bddc3ce0bcb115e
cheers
prev parent reply other threads:[~2017-12-22 4:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-05 5:30 [PATCH] powerpc/perf: Fix nest-imc cpuhotplug callback failure Anju T Sudhakar
2017-12-22 4:43 ` Michael Ellerman [this message]
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