From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754938AbbCBO2g (ORCPT ); Mon, 2 Mar 2015 09:28:36 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:16302 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754658AbbCBO0G (ORCPT ); Mon, 2 Mar 2015 09:26:06 -0500 From: Wang Nan To: , , , , CC: , , , Subject: [RFC PATCH v4 25/34] ftrace: don't fire ftrace_bug if the instruction is taken by early kprobes. Date: Mon, 2 Mar 2015 22:25:03 +0800 Message-ID: <1425306312-3437-26-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1425306312-3437-1-git-send-email-wangnan0@huawei.com> References: <1425306312-3437-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org During ftrace_init(), if an early kprobe has already probed at an instruction, don't fire ftrace_bug(). Instead, kprobe_fix_ftrace_make_nop() is for this fixing. It calls arch_fix_ftrace_early_kprobe() to adjust arch specific data. Following patches will convert such kprobes into ftrace. It's kprobe's responsibility for setting and clearing FTRACE_FL_EARLY_KPROBES flag. When ftrace try to makenop, set this flag. When ftrace try to create call instruction on it, unset it. Signed-off-by: Wang Nan --- include/linux/ftrace.h | 5 +++-- include/linux/kprobes.h | 7 +++++++ kernel/kprobes.c | 39 +++++++++++++++++++++++++++++++++++++++ kernel/trace/ftrace.c | 17 ++++++++++++----- 4 files changed, 61 insertions(+), 7 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 8db315a..fe99166 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -341,10 +341,11 @@ enum { FTRACE_FL_TRAMP = (1UL << 28), FTRACE_FL_TRAMP_EN = (1UL << 27), FTRACE_FL_IPMODIFY = (1UL << 26), + FTRACE_FL_EARLY_KPROBES = (1UL << 25), }; -#define FTRACE_REF_MAX_SHIFT 26 -#define FTRACE_FL_BITS 6 +#define FTRACE_REF_MAX_SHIFT 25 +#define FTRACE_FL_BITS 7 #define FTRACE_FL_MASKED_BITS ((1UL << FTRACE_FL_BITS) - 1) #define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT) #define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index f8f2ac2..ab1a330 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -282,10 +282,17 @@ extern void arch_fix_ftrace_early_kprobe(struct kprobe *kp, struct optimized_kprobe *op, int optimized); extern void init_kprobes_on_ftrace(void); +extern bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *rec); #else static inline void init_kprobes_on_ftrace(void) { } + +static inline bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *_unused) +{ + + return false; +} #endif // CONFIG_EARLY_KPROBES && CONFIG_KPROBES_ON_FTRACE #ifdef CONFIG_EARLY_KPROBES diff --git a/kernel/kprobes.c b/kernel/kprobes.c index b5e13ba..20b6ab8 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2584,6 +2584,45 @@ module_init(init_kprobes); EXPORT_SYMBOL_GPL(jprobe_return); #if defined(CONFIG_KPROBES_ON_FTRACE) && defined(CONFIG_EARLY_KPROBES) +bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *rec) +{ + struct optimized_kprobe *op; + struct kprobe *kp; + int optimized; + void *addr; + + if (kprobes_on_ftrace_initialized) + return false; + + addr = (void *)rec->ip; + mutex_lock(&kprobe_mutex); + kp = get_kprobe(addr); + + if (!kp || !(kp->flags & KPROBE_FLAG_FTRACE_EARLY)) { + mutex_unlock(&kprobe_mutex); + return false; + } + + op = kprobe_aggrprobe(kp) ? + container_of(kp, struct optimized_kprobe, kp) + : NULL; + + optimized = op ? op->kp.flags & KPROBE_FLAG_OPTIMIZED : 0; + arch_fix_ftrace_early_kprobe(kp, op, optimized); + if (op != NULL) { + struct kprobe *list_p; + + /* Fix all kprobes connected to it */ + list_for_each_entry_rcu(list_p, &op->kp.list, list) + arch_fix_ftrace_early_kprobe(list_p, NULL, optimized); + } + + mutex_unlock(&kprobe_mutex); + + rec->flags |= FTRACE_FL_EARLY_KPROBES; + return true; +} + void init_kprobes_on_ftrace(void) { kprobes_on_ftrace_initialized = true; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5cb0269..78787d4 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2387,11 +2387,18 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) return 0; ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); - if (ret) { - ftrace_bug(ret, rec); - return 0; - } - return 1; + + if (!ret) + return 1; + +#if defined(CONFIG_KPROBES_ON_FTRACE) && defined(CONFIG_EARLY_KPROBES) + /* FTRACE_FL_EARLY_KPROBES should have been set for rec */ + if (kprobe_fix_ftrace_make_nop(rec)) + return 1; +#endif + + ftrace_bug(ret, rec); + return 0; } /* -- 1.8.4