Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753716AbbF0Mgh (ORCPT ); Sat, 27 Jun 2015 08:36:37 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:63847 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752915AbbF0Mgc (ORCPT ); Sat, 27 Jun 2015 08:36:32 -0400 From: Wang Nan To: , , , , , , , , , , CC: , , , , Subject: [PATCH v2] bpf: Use correct #ifdef controller for trace_call_bpf() Date: Sat, 27 Jun 2015 12:36:01 +0000 Message-ID: <1435408561-24080-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1435407043-22864-1-git-send-email-wangnan0@huawei.com> References: <1435407043-22864-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.200] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2525 Lines: 64 Commit e1abf2cc8d5d80b41c4419368ec743ccadbb131e ("bpf: Fix the build on BPF_SYSCALL=y && !CONFIG_TRACING kernels, make it more configurable") updated the building condition of bpf_trace.o from CONFIG_BPF_SYSCALL to CONFIG_BPF_EVENTS, but the corresponding #ifdef controller in ftrace_event.h for trace_call_bpf() is not changed. Which, in theory, is incorrect. With current Kconfigs, we can create a .config with CONFIG_BPF_SYSCALL=y and CONFIG_BPF_EVENTS=n by unselecting CONFIG_KPROBE_EVENT and selecting CONFIG_BPF_SYSCALL. With these options, trace_call_bpf() will be defined as an extern function, but if anyone calls it a symbol missing error will be trigger since bpf_trace.o is not build. This patch changes the #ifdef controller for trace_call_bpf() from CONFIG_BPF_SYSCALL to CONFIG_BPF_EVENTS. I'll show its correctness: Before this patch: BPF_SYSCALL BPF_EVENTS trace_call_bpf bpf_trace.o y y normal compiled n n inline not compiled y n normal not compiled (incorrect) n y impossible (BPF_EVENTS depends on BPF_SYSCALL) After this patch: BPF_SYSCALL BPF_EVENTS trace_call_bpf bpf_trace.o y y normal compiled n n inline not compiled y n inline not compiled (fixed) n y impossible (BPF_EVENTS depends on BPF_SYSCALL) So this patch doesn't break thing. QED. Signed-off-by: Wang Nan --- v1 is incorrect: lost the 'S' in 'CONFIG_BPF_EVENTS'. Please ignore it. --- include/linux/ftrace_event.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index f9ecf63..ec48c92 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -553,7 +553,7 @@ event_trigger_unlock_commit_regs(struct ftrace_event_file *file, event_triggers_post_call(file, tt); } -#ifdef CONFIG_BPF_SYSCALL +#ifdef CONFIG_BPF_EVENTS unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx); #else static inline unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx) -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/