Merge: Updates for kernel tracing ring buffer

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4108

Description: Updates for kernel tracing ring buffer

JIRA: https://issues.redhat.com/browse/RHEL-23763

Build Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=60719054

Tested: Verified Brew build test kernel RPMs and confirmed issue is resovled

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

commit b71645d
Author: Zheng Yejian <zhengyejian1@huawei.com>
Date:   Sat Aug 5 11:38:15 2023 +0800

    tracing: Fix cpu buffers unavailable due to 'record_disabled' missed

    Trace ring buffer can no longer record anything after executing
    following commands at the shell prompt:
      fff
      -bash: echo: write error: Bad file descriptor

    The root cause is that:
      1. After `echo 0 > tracing_cpumask`, 'record_disabled' of cpu buffers
         in 'tr->array_buffer.buffer' became 1 (see tracing_set_cpumask());
      2. After `echo 1 > snapshot`, 'tr->array_buffer.buffer' is swapped
         with 'tr->max_buffer.buffer', then the 'record_disabled' became 0
         (see update_max_tr());
      3. After `echo fff > tracing_cpumask`, the 'record_disabled' become -1;
    Then array_buffer and max_buffer are both unavailable due to value of
    'record_disabled' is not 0.

    To fix it, enable or disable both array_buffer and max_buffer at the same
    time in tracing_set_cpumask().

    Link: https://lkml.kernel.org/r/20230805033816.3284594-2-zhengyejian1@huawei.com

    Cc: <mhiramat@kernel.org>
    Cc: <vnagarnaik@google.com>
    Cc: <shuah@kernel.org>
    Fixes: 71babb2 ("tracing: change CPU ring buffer state from tracing_cpumask")
    Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
    Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

Approved-by: Steve Best <sbest@redhat.com>
Approved-by: Tony Camuso <tcamuso@redhat.com>

Merged-by: Lucas Zampieri <lzampier@redhat.com>

Author: zampierilucas

kernel/trace/trace.c

@@ -5173,11 +5173,17 @@ int tracing_set_cpumask(struct trace_array *tr,
 				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
 			atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
 			ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
+#ifdef CONFIG_TRACER_MAX_TRACE
+			ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
+#endif
 		}
 		if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
 				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
 			atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
 			ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
+#ifdef CONFIG_TRACER_MAX_TRACE
+			ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
+#endif
 		}
 	}
 	arch_spin_unlock(&tr->max_lock);