From patchwork Wed Feb 10 10:21:57 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: 381788 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=-19.6 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, URIBL_BLOCKED, 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 09A54C433E9 for ; Wed, 10 Feb 2021 10:25:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B90E264E30 for ; Wed, 10 Feb 2021 10:25:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230280AbhBJKYy (ORCPT ); Wed, 10 Feb 2021 05:24:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:45850 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230489AbhBJKWl (ORCPT ); Wed, 10 Feb 2021 05:22:41 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 73DDF64E53; Wed, 10 Feb 2021 10:21:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612952520; bh=tMu8y9gKpKhT7k5kbtkYQ9wuDfv13TiiOrjpeMamVLI=; h=From:To:Cc:Subject:Date:From; b=T/eoxvZU/vI7isci0VpLO82SHdFSJAwK4gwGTHxwV7wh5FSnL5hJEyi/cbPXPY7D1 6WZ2+vhXwBRMOE4zYaNHxWZLJcNv3HnQkDnKu2DDRcReLywhGy+jMNrLiVShhl2/cc /WFzA+8TzvQk/nqCeRIetKtzCO9CnMfgPGIeM5axP8PCQZKp2eWUHubuWfSJmlOjaN gdrUbs8pOt8572z+ovPFUvBu4vAtJ3hMxPELiBQl+1SCqRhs9tOODE0bcaUV2W4Ino QdAFWLGTj5dmrUcoGWcykMkXnw0EUoCCAP5H2wellG9WlRdxmUHd70eqflSF4lt/13 gMLQl+LxywfEQ== From: Masami Hiramatsu To: stable@vger.kernel.org Cc: mhiramat@kernel.org, Jianlin.Lv@arm.com, rostedt@goodmis.org Subject: [PATCH 5.4.y] tracing/kprobe: Fix to support kretprobe events on unloaded modules Date: Wed, 10 Feb 2021 19:21:57 +0900 Message-Id: <161295251675.311731.1025064176598613505.stgit@devnote2> X-Mailer: git-send-email 2.25.1 User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 97c753e62e6c31a404183898d950d8c08d752dbd upstream. Fix kprobe_on_func_entry() returns error code instead of false so that register_kretprobe() can return an appropriate error code. append_trace_kprobe() expects the kprobe registration returns -ENOENT when the target symbol is not found, and it checks whether the target module is unloaded or not. If the target module doesn't exist, it defers to probe the target symbol until the module is loaded. However, since register_kretprobe() returns -EINVAL instead of -ENOENT in that case, it always fail on putting the kretprobe event on unloaded modules. e.g. Kprobe event: /sys/kernel/debug/tracing # echo p xfs:xfs_end_io >> kprobe_events [ 16.515574] trace_kprobe: This probe might be able to register after target module is loaded. Continue. Kretprobe event: (p -> r) /sys/kernel/debug/tracing # echo r xfs:xfs_end_io >> kprobe_events sh: write error: Invalid argument /sys/kernel/debug/tracing # cat error_log [ 41.122514] trace_kprobe: error: Failed to register probe event Command: r xfs:xfs_end_io ^ To fix this bug, change kprobe_on_func_entry() to detect symbol lookup failure and return -ENOENT in that case. Otherwise it returns -EINVAL or 0 (succeeded, given address is on the entry). Link: https://lkml.kernel.org/r/161176187132.1067016.8118042342894378981.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 59158ec4aef7 ("tracing/kprobes: Check the probe on unloaded module correctly") Reported-by: Jianlin Lv Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- include/linux/kprobes.h | 2 +- kernel/kprobes.c | 34 +++++++++++++++++++++++++--------- kernel/trace/trace_kprobe.c | 10 ++++++---- 3 files changed, 32 insertions(+), 14 deletions(-) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index a60488867dd0..a121fd8e7c3a 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -232,7 +232,7 @@ extern void kprobes_inc_nmissed_count(struct kprobe *p); extern bool arch_within_kprobe_blacklist(unsigned long addr); extern int arch_populate_kprobe_blacklist(void); extern bool arch_kprobe_on_func_entry(unsigned long offset); -extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset); +extern int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset); extern bool within_kprobe_blacklist(unsigned long addr); extern int kprobe_add_ksym_blacklist(unsigned long entry); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 283c8b01ce78..8f9fbc74021d 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1948,29 +1948,45 @@ bool __weak arch_kprobe_on_func_entry(unsigned long offset) return !offset; } -bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) +/** + * kprobe_on_func_entry() -- check whether given address is function entry + * @addr: Target address + * @sym: Target symbol name + * @offset: The offset from the symbol or the address + * + * This checks whether the given @addr+@offset or @sym+@offset is on the + * function entry address or not. + * This returns 0 if it is the function entry, or -EINVAL if it is not. + * And also it returns -ENOENT if it fails the symbol or address lookup. + * Caller must pass @addr or @sym (either one must be NULL), or this + * returns -EINVAL. + */ +int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) { kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset); if (IS_ERR(kp_addr)) - return false; + return PTR_ERR(kp_addr); - if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) || - !arch_kprobe_on_func_entry(offset)) - return false; + if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset)) + return -ENOENT; - return true; + if (!arch_kprobe_on_func_entry(offset)) + return -EINVAL; + + return 0; } int register_kretprobe(struct kretprobe *rp) { - int ret = 0; + int ret; struct kretprobe_instance *inst; int i; void *addr; - if (!kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset)) - return -EINVAL; + ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset); + if (ret) + return ret; if (kretprobe_blacklist_size) { addr = kprobe_addr(&rp->kp); diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 1074a69beff3..233322c77b76 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -220,9 +220,9 @@ bool trace_kprobe_on_func_entry(struct trace_event_call *call) { struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); - return tk ? kprobe_on_func_entry(tk->rp.kp.addr, + return tk ? (kprobe_on_func_entry(tk->rp.kp.addr, tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, - tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false; + tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false; } bool trace_kprobe_error_injectable(struct trace_event_call *call) @@ -811,9 +811,11 @@ static int trace_kprobe_create(int argc, const char *argv[]) trace_probe_log_err(0, BAD_PROBE_ADDR); goto parse_error; } - if (kprobe_on_func_entry(NULL, symbol, offset)) + ret = kprobe_on_func_entry(NULL, symbol, offset); + if (ret == 0) flags |= TPARG_FL_FENTRY; - if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { + /* Defer the ENOENT case until register kprobe */ + if (ret == -EINVAL && is_return) { trace_probe_log_err(0, BAD_RETPROBE); goto parse_error; }