From patchwork Thu Apr 27 01:19:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13225073 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 DD2C1C7618E for ; Thu, 27 Apr 2023 01:19:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242939AbjD0BTX (ORCPT ); Wed, 26 Apr 2023 21:19:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242904AbjD0BTP (ORCPT ); Wed, 26 Apr 2023 21:19:15 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EDD5A4236; Wed, 26 Apr 2023 18:19:06 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3B70B63A0A; Thu, 27 Apr 2023 01:19:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E688C433EF; Thu, 27 Apr 2023 01:19:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1682558345; bh=adT2gjGFemNwIn4O8ZHypQcbsWNS5Dz1HO4UfOkZlzk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qVTX4IrhgBaCqPEzpc3FvlfPG574yWr8CHOyReLnI1Ig55ERaSmwr8jZPXyhvzCCr CViuojMv3heKOcu2AucOs39NFFtWe5exz2EEo2wr28VQGj6TY24Fuputhn1m6zK1Jo w5FGwNn6CbHIUOtN2wb5NNB19tHt3Ja+XcFbbeyx+EplEeiGaU5CKXOmMHsbEyJ5eI qnEmjRPtJEdsatwxfV1vrS7UGlYhrXhOn3CXF1UgoPS4uuJgqDXVQ3L8v5g3+Y/fZ1 Ue35fD+ZALwjYU08tJNkzqlSTUtaurbt6lvSIHuNk9rAk9RNT5uCQ+kSJNy9evSrHs 96yotGbs6o0cQ== From: "Masami Hiramatsu (Google)" To: linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Steven Rostedt , mhiramat@kernel.org, Florent Revest , Mark Rutland , Will Deacon , Mathieu Desnoyers , Martin KaFai Lau , bpf@vger.kernel.org Subject: [PATCH v7 08/11] tracing/probes: Add BTF retval type support Date: Thu, 27 Apr 2023 10:19:01 +0900 Message-ID: <168255834145.2565678.12184411713423630481.stgit@mhiramat.roam.corp.google.com> X-Mailer: git-send-email 2.40.1.495.gc816e09b53d-goog In-Reply-To: <168255826500.2565678.17719875734305974633.stgit@mhiramat.roam.corp.google.com> References: <168255826500.2565678.17719875734305974633.stgit@mhiramat.roam.corp.google.com> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org From: Masami Hiramatsu (Google) Check the target function has non-void retval type and set the correct fetch type if user doesn't specify it. If the function returns void, $retval is rejected as below; # echo 'f unregister_kprobes%return $retval' >> dynamic_events sh: write error: No such file or directory # cat error_log [ 37.488397] trace_fprobe: error: This function returns 'void' type Command: f unregister_kprobes%return $retval ^ Signed-off-by: Masami Hiramatsu (Google) --- Changes in v7: - Introduce this as a new patch. --- kernel/trace/trace_probe.c | 65 +++++++++++++++++++++++++++++++++++++++++--- kernel/trace/trace_probe.h | 1 + 2 files changed, 61 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 4c3c70862a9a..16d8edfe3d15 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -371,13 +371,13 @@ static const char *type_from_btf_id(struct btf *btf, s32 id) return NULL; } -static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr) +static const struct btf_type *find_btf_func_proto(const char *funcname) { struct btf *btf = traceprobe_get_btf(); const struct btf_type *t; s32 id; - if (!btf || !funcname || !nr) + if (!btf || !funcname) return ERR_PTR(-EINVAL); id = btf_find_by_name_kind(btf, funcname, BTF_KIND_FUNC); @@ -394,6 +394,20 @@ static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr if (!btf_type_is_func_proto(t)) return ERR_PTR(-ENOENT); + return t; +} + +static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr) +{ + const struct btf_type *t; + + if (!funcname || !nr) + return ERR_PTR(-EINVAL); + + t = find_btf_func_proto(funcname); + if (IS_ERR(t)) + return (const struct btf_param *)t; + *nr = btf_type_vlen(t); if (*nr) @@ -452,6 +466,32 @@ static const struct fetch_type *parse_btf_arg_type(int arg_idx, return find_fetch_type(typestr, ctx->flags); } +static const struct fetch_type *parse_btf_retval_type( + struct traceprobe_parse_context *ctx) +{ + struct btf *btf = traceprobe_get_btf(); + const char *typestr = NULL; + const struct btf_type *t; + + if (btf && ctx->funcname) { + t = find_btf_func_proto(ctx->funcname); + if (!IS_ERR(t)) + typestr = type_from_btf_id(btf, t->type); + } + + return find_fetch_type(typestr, ctx->flags); +} + +static bool is_btf_retval_void(const char *funcname) +{ + const struct btf_type *t; + + t = find_btf_func_proto(funcname); + if (IS_ERR(t)) + return false; + + return t->type == 0; +} #else static struct btf *traceprobe_get_btf(void) { @@ -469,8 +509,15 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code, trace_probe_log_err(ctx->offset, NOSUP_BTFARG); return -EOPNOTSUPP; } + #define parse_btf_arg_type(idx, ctx) \ find_fetch_type(NULL, ctx->flags) + +#define parse_btf_retval_type(ctx) \ + find_fetch_type(NULL, ctx->flags) + +#define is_btf_retval_void(funcname) (false) + #endif #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) @@ -500,7 +547,12 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t, if (strcmp(arg, "retval") == 0) { if (ctx->flags & TPARG_FL_RETURN) { - code->op = FETCH_OP_RETVAL; + if ((ctx->flags & TPARG_FL_KERNEL) && + is_btf_retval_void(ctx->funcname)) { + trace_probe_log_err(ctx->offset, NO_RETVAL); + ret = -ENOENT; + } else + code->op = FETCH_OP_RETVAL; } else { trace_probe_log_err(ctx->offset, RETVAL_ON_PROBE); ret = -EINVAL; @@ -887,9 +939,12 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, goto fail; /* Update storing type if BTF is available */ - if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && - !t && code->op == FETCH_OP_ARG) + if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && !t) { + if (code->op == FETCH_OP_ARG) parg->type = parse_btf_arg_type(code->param, ctx); + else if (code->op == FETCH_OP_RETVAL) + parg->type = parse_btf_retval_type(ctx); + } ret = -EINVAL; /* Store operation */ diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 8c5b029c5d62..3eb7c37c0984 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -444,6 +444,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, C(BAD_EVENT_NAME, "Event name must follow the same rules as C identifiers"), \ C(EVENT_EXIST, "Given group/event name is already used by another event"), \ C(RETVAL_ON_PROBE, "$retval is not available on probe"), \ + C(NO_RETVAL, "This function returns 'void' type"), \ C(BAD_STACK_NUM, "Invalid stack number"), \ C(BAD_ARG_NUM, "Invalid argument number"), \ C(BAD_VAR, "Invalid $-valiable specified"), \