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authorNamhyung Kim <namhyung.kim@lge.com>2014-01-03 14:12:46 +0900
committerSteven Rostedt <rostedt@goodmis.org>2014-01-03 15:27:18 -0500
commite0d18fe063464cb3f1a6d1939e4fcf47d92d8386 (patch)
tree061fdc3f78de07af82fbe7695c3c5e78d896c3bd /kernel/trace/trace_probe.h
parentb7e0bf341f6cfa92ae0a0e3d0c3496729595e1e9 (diff)
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tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT
When kprobe-based dynamic event tracer is not enabled, it caused following build error: kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c8dd): undefined reference to `fetch_symbol_u8' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c8e9): undefined reference to `fetch_symbol_u16' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c8f5): undefined reference to `fetch_symbol_u32' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c901): undefined reference to `fetch_symbol_u64' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c909): undefined reference to `fetch_symbol_string' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c913): undefined reference to `fetch_symbol_string_size' ... It was due to the fetch methods are referred from CHECK_FETCH_FUNCS macro and since it was only defined in trace_kprobe.c. Move NULL definition of such fetch functions to the header file. Note, it also requires CONFIG_BRANCH_PROFILING enabled to trigger this failure as well. This is because the "fetch_symbol_*" variables are referenced in a "else if" statement that will only call update_symbol_cache(), which is a static inline stub function when CONFIG_KPROBE_EVENT is not enabled. gcc is smart enough to optimize this "else if" out and that also removes the code that references the undefined variables. But when BRANCH_PROFILING is enabled, it fools gcc into keeping the if statement around and thus references the undefined symbols and fails to build. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_probe.h')
-rw-r--r--kernel/trace/trace_probe.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index e29d743fef5d..b73574a5f429 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -243,6 +243,14 @@ unsigned long update_symbol_cache(struct symbol_cache *sc);
void free_symbol_cache(struct symbol_cache *sc);
struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
#else
+/* uprobes do not support symbol fetch methods */
+#define fetch_symbol_u8 NULL
+#define fetch_symbol_u16 NULL
+#define fetch_symbol_u32 NULL
+#define fetch_symbol_u64 NULL
+#define fetch_symbol_string NULL
+#define fetch_symbol_string_size NULL
+
struct symbol_cache {
};
static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)