From patchwork Fri Mar 26 12:29:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 12166511 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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 C0799C433E2 for ; Fri, 26 Mar 2021 12:30:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 864E661950 for ; Fri, 26 Mar 2021 12:30:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230012AbhCZM3i (ORCPT ); Fri, 26 Mar 2021 08:29:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:52748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230057AbhCZM3R (ORCPT ); Fri, 26 Mar 2021 08:29:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D42AD61948; Fri, 26 Mar 2021 12:29:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616761756; bh=BmKp/FA0g7ZOg1oLsp7e01PpVXipfwCQdHRKfNzoDDM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DbHxHWY/+57sLgxD4oQSXSGVBsvMAp/nPtE9vUfq7R1k/+m3uqAqYGSVwn2jpiZpw HWlktHF6KEQk9VYIHZn68ompe/tvAIU02GD+AWbUDgrjh/p/QAh9nBt/Lu3dAivYXD 1GAkvMXZw0RrJjrxqvbd3vt6gIYp2TISoKBVzte/FFg//oGEigJCVyijAZvzturpOU zmDDOYXI8BSWolQEQp9wId0631/El8QuXHY9XbzGPmifYXO68mzn9aGE0tzG4CMcoa yX6mHS6gRhxmbpbLiS8mrZz2+yctCHDk57egtzWkAdEwyYUpiOYPfpNzcYrT/NhfEu JmcGbDPj9wktg== From: Masami Hiramatsu To: Steven Rostedt , Ingo Molnar Cc: X86 ML , Masami Hiramatsu , Daniel Xu , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com, Josh Poimboeuf , linux-ia64@vger.kernel.org, Abhishek Sagar Subject: [PATCH -tip v5 04/12] kprobes: Add kretprobe_find_ret_addr() for searching return address Date: Fri, 26 Mar 2021 21:29:10 +0900 Message-Id: <161676174991.330141.9859982513687549125.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <161676170650.330141.6214727134265514123.stgit@devnote2> References: <161676170650.330141.6214727134265514123.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add kretprobe_find_ret_addr() for searching correct return address from kretprobe instance list. Signed-off-by: Masami Hiramatsu --- Changes in v3: - Remove generic stacktrace fixup. Instead, it should be solved in each unwinder. This just provide the generic interface. Changes in v2: - Add is_kretprobe_trampoline() for checking address outside of kretprobe_find_ret_addr() - Remove unneeded addr from kretprobe_find_ret_addr() - Rename fixup_kretprobe_tramp_addr() to fixup_kretprobe_trampoline() --- include/linux/kprobes.h | 22 +++++++++++ kernel/kprobes.c | 90 +++++++++++++++++++++++++++++++++-------------- 2 files changed, 86 insertions(+), 26 deletions(-) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 65dadd4238a2..f530f82a046d 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -215,6 +215,14 @@ static nokprobe_inline void *kretprobe_trampoline_addr(void) return dereference_function_descriptor(kretprobe_trampoline); } +static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr) +{ + return (void *)addr == kretprobe_trampoline_addr(); +} + +unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp, + struct llist_node **cur); + /* If the trampoline handler called from a kprobe, use this version */ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, void *frame_pointer); @@ -514,6 +522,20 @@ static inline bool is_kprobe_optinsn_slot(unsigned long addr) } #endif +#if !defined(CONFIG_KRETPROBES) +static nokprobe_inline bool is_kretprobe_trampoline(unsigned long addr) +{ + return false; +} + +static nokprobe_inline +unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp, + struct llist_node **cur) +{ + return 0; +} +#endif + /* Returns true if kprobes handled the fault */ static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs, unsigned int trap) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 75c0a58c19c2..cf19edc038e4 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1858,45 +1858,68 @@ static struct notifier_block kprobe_exceptions_nb = { #ifdef CONFIG_KRETPROBES -unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, - void *frame_pointer) +/* This assumes the tsk is current or the task which is not running. */ +static unsigned long __kretprobe_find_ret_addr(struct task_struct *tsk, + struct llist_node **cur) { - kprobe_opcode_t *correct_ret_addr = NULL; struct kretprobe_instance *ri = NULL; - struct llist_node *first, *node; - struct kretprobe *rp; + struct llist_node *node = *cur; + + if (!node) + node = tsk->kretprobe_instances.first; + else + node = node->next; - /* Find all nodes for this frame. */ - first = node = current->kretprobe_instances.first; while (node) { ri = container_of(node, struct kretprobe_instance, llist); - - BUG_ON(ri->fp != frame_pointer); - if (ri->ret_addr != kretprobe_trampoline_addr()) { - correct_ret_addr = ri->ret_addr; - /* - * This is the real return address. Any other - * instances associated with this task are for - * other calls deeper on the call stack - */ - goto found; + *cur = node; + return (unsigned long)ri->ret_addr; } - node = node->next; } - pr_err("Oops! Kretprobe fails to find correct return address.\n"); - BUG_ON(1); + return 0; +} +NOKPROBE_SYMBOL(__kretprobe_find_ret_addr); -found: - /* Unlink all nodes for this frame. */ - current->kretprobe_instances.first = node->next; - node->next = NULL; +unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp, + struct llist_node **cur) +{ + struct kretprobe_instance *ri = NULL; + unsigned long ret; + + do { + ret = __kretprobe_find_ret_addr(tsk, cur); + if (!ret) + return ret; + ri = container_of(*cur, struct kretprobe_instance, llist); + } while (ri->fp != fp); + + return ret; +} +NOKPROBE_SYMBOL(kretprobe_find_ret_addr); - /* Run them.. */ +unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, + void *frame_pointer) +{ + kprobe_opcode_t *correct_ret_addr = NULL; + struct kretprobe_instance *ri = NULL; + struct llist_node *first, *node = NULL; + struct kretprobe *rp; + + /* Find correct address and all nodes for this frame. */ + correct_ret_addr = (void *)__kretprobe_find_ret_addr(current, &node); + if (!correct_ret_addr) { + pr_err("Oops! Kretprobe fails to find correct return address.\n"); + BUG_ON(1); + } + + /* Run them. */ + first = current->kretprobe_instances.first; while (first) { ri = container_of(first, struct kretprobe_instance, llist); - first = first->next; + + BUG_ON(ri->fp != frame_pointer); rp = get_kretprobe(ri); if (rp && rp->handler) { @@ -1907,6 +1930,21 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, rp->handler(ri, regs); __this_cpu_write(current_kprobe, prev); } + if (first == node) + break; + + first = first->next; + } + + /* Unlink all nodes for this frame. */ + first = current->kretprobe_instances.first; + current->kretprobe_instances.first = node->next; + node->next = NULL; + + /* Recycle them. */ + while (first) { + ri = container_of(first, struct kretprobe_instance, llist); + first = first->next; recycle_rp_inst(ri); }