From: Namhyung Kim Date: Fri, 3 Jan 2014 05:12:46 +0000 (+0900) Subject: tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT X-Git-Tag: v3.14-rc1~133^2~10 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e0d18fe063464cb3f1a6d1939e4fcf47d92d8386;p=pandora-kernel.git 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 Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- Reading git-diff-tree failed