* [PATCH v2] powerpc/perf: Disable trace_imc pmu
@ 2019-11-18 3:44 Madhavan Srinivasan
2019-11-22 8:03 ` Hariharan T S
2019-12-09 5:45 ` Michael Ellerman
0 siblings, 2 replies; 3+ messages in thread
From: Madhavan Srinivasan @ 2019-11-18 3:44 UTC (permalink / raw)
To: mpe; +Cc: Madhavan Srinivasan, linuxppc-dev
When a root user or a user with CAP_SYS_ADMIN
privilege use trace_imc performance monitoring
unit events, to monitor application or KVM threads,
may result in a checkstop (System crash). Reason
being frequent switch of the "trace/accumulation"
mode of In-Memory Collection hardware.
This patch disables trace_imc pmu unit, but will
be re-enabled at a later stage with a fix patchset.
Fixes: 012ae244845f1 ('powerpc/perf: Trace imc PMU functions')
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
---
Changelog v1:
- Added fixes and signed-off by.
arch/powerpc/platforms/powernv/opal-imc.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
index e04b20625cb9..5790f078771f 100644
--- a/arch/powerpc/platforms/powernv/opal-imc.c
+++ b/arch/powerpc/platforms/powernv/opal-imc.c
@@ -285,7 +285,12 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
domain = IMC_DOMAIN_THREAD;
break;
case IMC_TYPE_TRACE:
- domain = IMC_DOMAIN_TRACE;
+ /* Using trace_imc events to monitor
+ * application or KVM thread performances
+ * may result in a checkstop (system crash).
+ * So disabling it for now.
+ */
+ domain = -1;
break;
default:
pr_warn("IMC Unknown Device type \n");
--
2.21.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] powerpc/perf: Disable trace_imc pmu
2019-11-18 3:44 [PATCH v2] powerpc/perf: Disable trace_imc pmu Madhavan Srinivasan
@ 2019-11-22 8:03 ` Hariharan T S
2019-12-09 5:45 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Hariharan T S @ 2019-11-22 8:03 UTC (permalink / raw)
To: linuxppc-dev
On 11/18/19 9:14 AM, Madhavan Srinivasan wrote:
> When a root user or a user with CAP_SYS_ADMIN
> privilege use trace_imc performance monitoring
> unit events, to monitor application or KVM threads,
> may result in a checkstop (System crash). Reason
> being frequent switch of the "trace/accumulation"
> mode of In-Memory Collection hardware.
> This patch disables trace_imc pmu unit, but will
> be re-enabled at a later stage with a fix patchset.
>
> Fixes: 012ae244845f1 ('powerpc/perf: Trace imc PMU functions')
> Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Tested-by: Hariharan T.S. <hari@linux.ibm.com>
> ---
> Changelog v1:
> - Added fixes and signed-off by.
> arch/powerpc/platforms/powernv/opal-imc.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
> index e04b20625cb9..5790f078771f 100644
> --- a/arch/powerpc/platforms/powernv/opal-imc.c
> +++ b/arch/powerpc/platforms/powernv/opal-imc.c
> @@ -285,7 +285,12 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
> domain = IMC_DOMAIN_THREAD;
> break;
> case IMC_TYPE_TRACE:
> - domain = IMC_DOMAIN_TRACE;
> + /* Using trace_imc events to monitor
> + * application or KVM thread performances
> + * may result in a checkstop (system crash).
> + * So disabling it for now.
> + */
> + domain = -1;
> break;
> default:
> pr_warn("IMC Unknown Device type \n");
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] powerpc/perf: Disable trace_imc pmu
2019-11-18 3:44 [PATCH v2] powerpc/perf: Disable trace_imc pmu Madhavan Srinivasan
2019-11-22 8:03 ` Hariharan T S
@ 2019-12-09 5:45 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2019-12-09 5:45 UTC (permalink / raw)
To: Madhavan Srinivasan; +Cc: Madhavan Srinivasan, linuxppc-dev
On Mon, 2019-11-18 at 03:44:52 UTC, Madhavan Srinivasan wrote:
> When a root user or a user with CAP_SYS_ADMIN
> privilege use trace_imc performance monitoring
> unit events, to monitor application or KVM threads,
> may result in a checkstop (System crash). Reason
> being frequent switch of the "trace/accumulation"
> mode of In-Memory Collection hardware.
> This patch disables trace_imc pmu unit, but will
> be re-enabled at a later stage with a fix patchset.
>
> Fixes: 012ae244845f1 ('powerpc/perf: Trace imc PMU functions')
> Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/249fad734a25889a4f23ed014d43634af6798063
cheers
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-11-22 8:03 ` Hariharan T S
2019-12-09 5:45 ` Michael Ellerman
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