From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755322AbaAFPlR (ORCPT ); Mon, 6 Jan 2014 10:41:17 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.225]:20664 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751446AbaAFPlP (ORCPT ); Mon, 6 Jan 2014 10:41:15 -0500 Date: Mon, 6 Jan 2014 10:41:13 -0500 From: Steven Rostedt To: LKML Cc: Ingo Molnar , Frederic Weisbecker , Namhyung Kim Subject: [for-next][PATCH] tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT Message-ID: <20140106104113.237f5f54@gandalf.local.home> X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.22; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next Head SHA1: e0d18fe063464cb3f1a6d1939e4fcf47d92d8386 Namhyung Kim (1): tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT ---- kernel/trace/trace_probe.h | 8 ++++++++ kernel/trace/trace_uprobe.c | 8 -------- 2 files changed, 8 insertions(+), 8 deletions(-) --------------------------- commit e0d18fe063464cb3f1a6d1939e4fcf47d92d8386 Author: Namhyung Kim Date: Fri Jan 3 14:12:46 2014 +0900 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 diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index e29d743..b73574a 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) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 1fdea6d..79e52d9 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -172,14 +172,6 @@ static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, *(u32 *)dest = len; } -/* 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 - static unsigned long translate_user_vaddr(void *file_offset) { unsigned long base_addr;