Re: [PATCH v2] powerpc/perf: Disable trace_imc pmu
From: Hariharan T S <hidden>
Date: 2019-11-22 08:42:24
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 <redacted>Tested-by: Hariharan T.S. <redacted>
quoted hunk ↗ jump to hunk
--- 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");