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 X-Spam-Level: X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9313C433DF for ; Wed, 26 Aug 2020 13:46:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 958A722B43 for ; Wed, 26 Aug 2020 13:46:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598449608; bh=XjZO2OiSEuQv7nUt7SYVCl/oeKTyNLaTG8RxmW3XU+Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zaobgFqhK2mACmq84lNcv4Fdgsu+8ppEU9sPM6ddoHPqWh+QOWdyulRPQ0WRS38WF cHZtKr24tFVVMrSZHIrAbw7Vdw7cCrwFNTVVHSPs/LdbyXJUAqjSS1kXZF7Z8Qubhr 53+waNGW5csDsoEY/jN7nQNpty/PKGbVicPPgjws= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730399AbgHZNqq (ORCPT ); Wed, 26 Aug 2020 09:46:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:56270 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730306AbgHZNqi (ORCPT ); Wed, 26 Aug 2020 09:46:38 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AC2F2221E2; Wed, 26 Aug 2020 13:46:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598449598; bh=XjZO2OiSEuQv7nUt7SYVCl/oeKTyNLaTG8RxmW3XU+Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gi/LsUkqpRaIopAZUkNMmGnDZaRgd0/SSf7kdQL41o3S3iWn5NQoaBQF6FhSaqAa8 kd0p0KPv/nNDj44ShDihViqofAFN6zoCNUCJF2SH27R8peUWbG29U7iLRI2IGbNilW KksXrzMwYwE6KgGRzaCeMhWfkTLz+te+eVvQ0jKI= From: Masami Hiramatsu To: Peter Zijlstra Cc: Eddy Wu , linux-kernel@vger.kernel.org, x86@kernel.org, "David S . Miller" , Steven Rostedt , Ingo Molnar , "Naveen N . Rao" , Anil S Keshavamurthy , linux-arch@vger.kernel.org Subject: [RFC PATCH 02/14] x86/kprobes: Use generic kretprobe trampoline handler Date: Wed, 26 Aug 2020 22:46:33 +0900 Message-Id: <159844959341.510284.56493231485723489.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <159844957216.510284.17683703701627367133.stgit@devnote2> References: <159844957216.510284.17683703701627367133.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Masami Hiramatsu --- arch/x86/kernel/kprobes/core.c | 109 +--------------------------------------- 1 file changed, 4 insertions(+), 105 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 2ca10b770cff..45cfaa097110 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -767,123 +767,22 @@ asm( NOKPROBE_SYMBOL(kretprobe_trampoline); STACK_FRAME_NON_STANDARD(kretprobe_trampoline); + /* * Called from kretprobe_trampoline */ __used __visible void *trampoline_handler(struct pt_regs *regs) { - struct kretprobe_instance *ri = NULL; - struct hlist_head *head, empty_rp; - struct hlist_node *tmp; - unsigned long flags, orig_ret_address = 0; - unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; - kprobe_opcode_t *correct_ret_addr = NULL; - void *frame_pointer; - bool skipped = false; - - /* - * Set a dummy kprobe for avoiding kretprobe recursion. - * Since kretprobe never run in kprobe handler, kprobe must not - * be running at this point. - */ - kprobe_busy_begin(); - - INIT_HLIST_HEAD(&empty_rp); - kretprobe_hash_lock(current, &head, &flags); /* fixup registers */ regs->cs = __KERNEL_CS; #ifdef CONFIG_X86_32 regs->gs = 0; #endif - /* We use pt_regs->sp for return address holder. */ - frame_pointer = ®s->sp; - regs->ip = trampoline_address; + regs->ip = (unsigned long)&kretprobe_trampoline; regs->orig_ax = ~0UL; - /* - * It is possible to have multiple instances associated with a given - * task either because multiple functions in the call path have - * return probes installed on them, and/or more than one - * return probe was registered for a target function. - * - * We can handle this because: - * - instances are always pushed into the head of the list - * - when multiple return probes are registered for the same - * function, the (chronologically) first instance's ret_addr - * will be the real return address, and all the rest will - * point to kretprobe_trampoline. - */ - hlist_for_each_entry(ri, head, hlist) { - if (ri->task != current) - /* another task is sharing our hash bucket */ - continue; - /* - * Return probes must be pushed on this hash list correct - * order (same as return order) so that it can be popped - * correctly. However, if we find it is pushed it incorrect - * order, this means we find a function which should not be - * probed, because the wrong order entry is pushed on the - * path of processing other kretprobe itself. - */ - if (ri->fp != frame_pointer) { - if (!skipped) - pr_warn("kretprobe is stacked incorrectly. Trying to fixup.\n"); - skipped = true; - continue; - } - - orig_ret_address = (unsigned long)ri->ret_addr; - if (skipped) - pr_warn("%ps must be blacklisted because of incorrect kretprobe order\n", - ri->rp->kp.addr); - - if (orig_ret_address != trampoline_address) - /* - * This is the real return address. Any other - * instances associated with this task are for - * other calls deeper on the call stack - */ - break; - } - - kretprobe_assert(ri, orig_ret_address, trampoline_address); - - correct_ret_addr = ri->ret_addr; - hlist_for_each_entry_safe(ri, tmp, head, hlist) { - if (ri->task != current) - /* another task is sharing our hash bucket */ - continue; - if (ri->fp != frame_pointer) - continue; - - orig_ret_address = (unsigned long)ri->ret_addr; - if (ri->rp && ri->rp->handler) { - __this_cpu_write(current_kprobe, &ri->rp->kp); - ri->ret_addr = correct_ret_addr; - ri->rp->handler(ri, regs); - __this_cpu_write(current_kprobe, &kprobe_busy); - } - - recycle_rp_inst(ri, &empty_rp); - - if (orig_ret_address != trampoline_address) - /* - * This is the real return address. Any other - * instances associated with this task are for - * other calls deeper on the call stack - */ - break; - } - - kretprobe_hash_unlock(current, &flags); - - kprobe_busy_end(); - - hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { - hlist_del(&ri->hlist); - kfree(ri); - } - return (void *)orig_ret_address; + return (void *)kretprobe_trampoline_handler(regs, + (unsigned long)&kretprobe_trampoline, ®s->sp); } NOKPROBE_SYMBOL(trampoline_handler);