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Madhavan Srinivasan authored
When a root user or a user with CAP_SYS_ADMIN privilege uses any trace_imc performance monitoring unit events, to monitor application or KVM threads, it may result in a checkstop (System crash). The cause is frequent switching of the "trace/accumulation" mode of the In-Memory Collection hardware (LDBAR). This patch disables the trace_imc PMU unit entirely to avoid triggering the checkstop. A future patch will reenable it at a later stage once a workaround has been developed. Fixes: 012ae244 ("powerpc/perf: Trace imc PMU functions") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by:
Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Tested-by:
Hariharan T.S. <hari@linux.ibm.com> [mpe: Add pr_info_once() so dmesg shows the PMU has been disabled] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191118034452.9939-1-maddy@linux.vnet.ibm.com
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