tracing/markers: make markers select tracepoints

Sometimes it happens that KConfig dependencies are not handled
like in the following scenario:

- config A
   bool

- config B
   bool
   depends on A

- config C
   bool
   select B

If one selects C, then it will select B without checking its
dependency to A, if A hasn't been selected elsewhere, it will
result in a build failure.

This is what happens on the following build error:

 kernel/built-in.o: In function `marker_update_probe_range':
 (.text+0x52f64): undefined reference to `tracepoint_probe_register_noupdate'
 kernel/built-in.o: In function `marker_update_probe_range':
 (.text+0x52f74): undefined reference to `tracepoint_probe_unregister_noupdate'
 kernel/built-in.o: In function `marker_update_probe_range':
 (.text+0x52fb9): undefined reference to `tracepoint_probe_unregister_noupdate'
 kernel/built-in.o: In function `marker_update_probes':
 marker.c:(.text+0x530ba): undefined reference to `tracepoint_probe_update_all'

CONFIG_KVM_TRACE will select CONFIG_MARKER, but the latter
depends on CONFIG_TRACEPOINTS which will not be selected.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/init/Kconfig b/init/Kconfig
index f068071fcc5d952a0a6c7d745797ea094d7b3999..26b5bab6f6e82810b2f9fa4122c670e0b677cab7 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -945,7 +945,7 @@ config TRACEPOINTS
 
 config MARKERS
        bool "Activate markers"
-       depends on TRACEPOINTS
+       select TRACEPOINTS
        help
          Place an empty function call at each marker site. Can be
          dynamically changed for a probe function.