From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 768B5C433EF for ; Tue, 15 Mar 2022 10:46:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347498AbiCOKr3 (ORCPT ); Tue, 15 Mar 2022 06:47:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347354AbiCOKpi (ORCPT ); Tue, 15 Mar 2022 06:45:38 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C257038D80; Tue, 15 Mar 2022 03:44:05 -0700 (PDT) Date: Tue, 15 Mar 2022 10:44:03 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1647341044; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=C2HyyTEWIqVtkTUsOloI1HEApvjMCe9j9P8JDU1lvGw=; b=10HCpvco2TBNjCv2RPR6Z/HzOuaKEWKZae+NxheySm7/eJmSHRCQxP7LAJybXU3uFa1mft Ky41w//A46IyQ+7yXr5Z0TNLdTAqc9K00ECBse1OFRaT2c1g8yKoTm6qe70bzNPoDc2N16 LnfJZe6umxR4NhWbVXQpMxy3zD3D5NPVui+MM36A0wGSt/vSfr3UHtKNk8kYKLcuJDPjRj mCVDW42Xj6E9oa9KS3O53RMeu6vPOuYuK16mVXGRzBBYoqwTEbooYUC+1nY9p/OrxiWCqk POpqaZjSnxeEC/i6m1/yqQQ9py9uROhQX/oUWgCUb5PpmyaxTnC/cVldAcI78g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1647341044; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=C2HyyTEWIqVtkTUsOloI1HEApvjMCe9j9P8JDU1lvGw=; b=SJgMzIYoQKLuUqohnsVugXCbAbDZpggo+3FFjBAMov37xSuow0EE6yPyNvredPcw/jhz6T /LLGP8MOezf4SkCg== From: "tip-bot2 for Peter Zijlstra" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/core] x86/ibt,ftrace: Search for __fentry__ location Cc: Steven Rostedt , "Peter Zijlstra (Intel)" , Masami Hiramatsu , Josh Poimboeuf , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20220308154318.227581603@infradead.org> References: <20220308154318.227581603@infradead.org> MIME-Version: 1.0 Message-ID: <164734104336.16921.9720913564142256546.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/core branch of tip: Commit-ID: aebfd12521d9c7d0b502cf6d06314cfbcdccfe3b Gitweb: https://git.kernel.org/tip/aebfd12521d9c7d0b502cf6d06314cfbcdccfe3b Author: Peter Zijlstra AuthorDate: Tue, 08 Mar 2022 16:30:29 +01:00 Committer: Peter Zijlstra CommitterDate: Tue, 15 Mar 2022 10:32:37 +01:00 x86/ibt,ftrace: Search for __fentry__ location Currently a lot of ftrace code assumes __fentry__ is at sym+0. However with Intel IBT enabled the first instruction of a function will most likely be ENDBR. Change ftrace_location() to not only return the __fentry__ location when called for the __fentry__ location, but also when called for the sym+0 location. Then audit/update all callsites of this function to consistently use these new semantics. Suggested-by: Steven Rostedt Signed-off-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154318.227581603@infradead.org --- arch/x86/kernel/kprobes/core.c | 11 +------- kernel/bpf/trampoline.c | 20 ++------------ kernel/kprobes.c | 8 +----- kernel/trace/ftrace.c | 48 +++++++++++++++++++++++++++------ 4 files changed, 48 insertions(+), 39 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 6290712..4d8086a 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -193,17 +193,10 @@ static unsigned long __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) { struct kprobe *kp; - unsigned long faddr; + bool faddr; kp = get_kprobe((void *)addr); - faddr = ftrace_location(addr); - /* - * Addresses inside the ftrace location are refused by - * arch_check_ftrace_location(). Something went terribly wrong - * if such an address is checked here. - */ - if (WARN_ON(faddr && faddr != addr)) - return 0UL; + faddr = ftrace_location(addr) == addr; /* * Use the current code if it is not modified by Kprobe * and it cannot be modified by ftrace. diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 5e7edf9..455f1b4 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -117,18 +117,6 @@ static void bpf_trampoline_module_put(struct bpf_trampoline *tr) tr->mod = NULL; } -static int is_ftrace_location(void *ip) -{ - long addr; - - addr = ftrace_location((long)ip); - if (!addr) - return 0; - if (WARN_ON_ONCE(addr != (long)ip)) - return -EFAULT; - return 1; -} - static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr) { void *ip = tr->func.addr; @@ -160,12 +148,12 @@ static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_ad static int register_fentry(struct bpf_trampoline *tr, void *new_addr) { void *ip = tr->func.addr; + unsigned long faddr; int ret; - ret = is_ftrace_location(ip); - if (ret < 0) - return ret; - tr->func.ftrace_managed = ret; + faddr = ftrace_location((unsigned long)ip); + if (faddr) + tr->func.ftrace_managed = true; if (bpf_trampoline_module_get(tr)) return -ENOENT; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 94cab8c..6d1e11c 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1562,14 +1562,10 @@ static inline int warn_kprobe_rereg(struct kprobe *p) static int check_ftrace_location(struct kprobe *p) { - unsigned long ftrace_addr; + unsigned long addr = (unsigned long)p->addr; - ftrace_addr = ftrace_location((unsigned long)p->addr); - if (ftrace_addr) { + if (ftrace_location(addr) == addr) { #ifdef CONFIG_KPROBES_ON_FTRACE - /* Given address is not on the instruction boundary */ - if ((unsigned long)p->addr != ftrace_addr) - return -EILSEQ; p->flags |= KPROBE_FLAG_FTRACE; #else /* !CONFIG_KPROBES_ON_FTRACE */ return -EINVAL; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6105b70..2ae6fb9 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1568,17 +1568,34 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end) } /** - * ftrace_location - return true if the ip giving is a traced location + * ftrace_location - return the ftrace location * @ip: the instruction pointer to check * - * Returns rec->ip if @ip given is a pointer to a ftrace location. - * That is, the instruction that is either a NOP or call to - * the function tracer. It checks the ftrace internal tables to - * determine if the address belongs or not. + * If @ip matches the ftrace location, return @ip. + * If @ip matches sym+0, return sym's ftrace location. + * Otherwise, return 0. */ unsigned long ftrace_location(unsigned long ip) { - return ftrace_location_range(ip, ip); + struct dyn_ftrace *rec; + unsigned long offset; + unsigned long size; + + rec = lookup_rec(ip, ip); + if (!rec) { + if (!kallsyms_lookup_size_offset(ip, &size, &offset)) + goto out; + + /* map sym+0 to __fentry__ */ + if (!offset) + rec = lookup_rec(ip, ip + size - 1); + } + + if (rec) + return rec->ip; + +out: + return 0; } /** @@ -4962,7 +4979,8 @@ ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) { struct ftrace_func_entry *entry; - if (!ftrace_location(ip)) + ip = ftrace_location(ip); + if (!ip) return -EINVAL; if (remove) { @@ -5110,11 +5128,16 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr) struct ftrace_func_entry *entry; struct ftrace_hash *free_hash = NULL; struct dyn_ftrace *rec; - int ret = -EBUSY; + int ret = -ENODEV; mutex_lock(&direct_mutex); + ip = ftrace_location(ip); + if (!ip) + goto out_unlock; + /* See if there's a direct function at @ip already */ + ret = -EBUSY; if (ftrace_find_rec_direct(ip)) goto out_unlock; @@ -5222,6 +5245,10 @@ int unregister_ftrace_direct(unsigned long ip, unsigned long addr) mutex_lock(&direct_mutex); + ip = ftrace_location(ip); + if (!ip) + goto out_unlock; + entry = find_direct_entry(&ip, NULL); if (!entry) goto out_unlock; @@ -5354,6 +5381,11 @@ int modify_ftrace_direct(unsigned long ip, mutex_lock(&direct_mutex); mutex_lock(&ftrace_lock); + + ip = ftrace_location(ip); + if (!ip) + goto out_unlock; + entry = find_direct_entry(&ip, &rec); if (!entry) goto out_unlock;