From patchwork Mon Oct 25 20:08:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 12582865 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2391DC433EF for ; Mon, 25 Oct 2021 20:23:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0CDB760724 for ; Mon, 25 Oct 2021 20:23:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238471AbhJYU0A (ORCPT ); Mon, 25 Oct 2021 16:26:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237910AbhJYUZj (ORCPT ); Mon, 25 Oct 2021 16:25:39 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3DF73C04A41F for ; Mon, 25 Oct 2021 13:10:43 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id k22-20020a25b296000000b005c14f7662b6so11953367ybj.2 for ; Mon, 25 Oct 2021 13:10:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=PgMb11rYRqtDORRAJvUgAM6VEyAICR6ozOy7CkCp1d8=; b=cfydvUIBwsMpyTEUsBxiqkD7qJIrnXKN6gU7AxG27BYqI3ZJofd5NxQFjGgY5xrGFy fcoCa26C+izcDXPsPleAE2l1hagJm28QTAu0XQcEESHs2CC+YDvA0V7v7PDuIe5HwURV RmJLzEljWR390h0OKCfzR+weKjWXcavpR6yxo34J+7+c0ygTXWUVVC0vhqjj9cnT/HKU LsKs1kGBsE2eTvb/5925j6Jh0KnbchLtXVMiBdQg/D+mxz+21YGUJdgRgzufzVNz3Xk/ +JwiKhor7J+fyBux/QWHXzOVAThMgJq7TVtplP58qOFGma+ZibcBir4YEbeAVB33m4RY wIAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=PgMb11rYRqtDORRAJvUgAM6VEyAICR6ozOy7CkCp1d8=; b=GdHVZuAG3UfCcgZzc0XRUX/vspo/g0u7b/1e33QBX1uS6FTjRBpWvM8siQ+qSNecYY Px9kpOn3HI/cus9WQHY27dA3u9tIxtfuMxQRy627pF1v6CRb1VJd8ScxfyTtTP19j/MT wKsgp80Ic6ZMFnoUE+wHRApY/EUHTK0PDXKyH3Mxkj+EVjvC0MDNu0CX++kSwxIJkQuw mtN14kfFwV4OUUpaJONeSTbhwMAaWcYwU5BIfQciNa5p4p7jUIblPtfws2daLxWXd0QC mFA9oDnmwm0PrzxOClArZ1/YN3J9rqQCEzX7jKeKU2DEoDfd64EXmCVLtn0v5LxonCQA SsAg== X-Gm-Message-State: AOAM533av3c0OuqWYLkJQawupRYiKWD4lBhuJq9+a4S/vyDm+Knv4tlx dZFhgUA2+3m8vgGJ6yXmFWkGZAl1UNdLaTy5MQ== X-Google-Smtp-Source: ABdhPJxheJji8hzdIygV2zHaLxRA6k79qhZpe1oSCFcqhVGHfxUqNGcUFaPjJ4TpK+af3/bXNJ1x8ZRHFmP82zNXAQ== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:b783:5702:523e:d435]) (user=kaleshsingh job=sendgmr) by 2002:a25:ea0a:: with SMTP id p10mr16539542ybd.520.1635192642476; Mon, 25 Oct 2021 13:10:42 -0700 (PDT) Date: Mon, 25 Oct 2021 13:08:36 -0700 In-Reply-To: <20211025200852.3002369-1-kaleshsingh@google.com> Message-Id: <20211025200852.3002369-5-kaleshsingh@google.com> Mime-Version: 1.0 References: <20211025200852.3002369-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog Subject: [PATCH v4 4/8] tracing/histogram: Simplify handling of .sym-offset in expressions From: Kalesh Singh Cc: surenb@google.com, hridya@google.com, namhyung@kernel.org, kernel-team@android.com, Kalesh Singh , Steven Rostedt , Jonathan Corbet , Ingo Molnar , Shuah Khan , Masami Hiramatsu , Tom Zanussi , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org The '-' in .sym-offset can confuse the hist trigger arithmetic expression parsing. Simplify the handling of this by replacing the 'sym-offset' with 'symXoffset'. This allows us to correctly evaluate expressions where the user may have inadvertently added a .sym-offset modifier to one of the operands in an expression, instead of bailing out. In this case the .sym-offset has no effect on the evaluation of the expression. The only valid use of the .sym-offset is as a hist key modifier. Signed-off-by: Kalesh Singh Suggested-by: Steven Rostedt --- kernel/trace/trace_events_hist.c | 43 +++++++++++++------------------- 1 file changed, 17 insertions(+), 26 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index e10c7d9611e5..34aba07d23f8 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -68,8 +68,7 @@ C(INVALID_SORT_FIELD, "Sort field must be a key or a val"), \ C(INVALID_STR_OPERAND, "String type can not be an operand in expression"), \ C(EXPECT_NUMBER, "Expecting numeric literal"), \ - C(UNARY_MINUS_SUBEXPR, "Unary minus not supported in sub-expressions"), \ - C(SYM_OFFSET_SUBEXPR, ".sym-offset not supported in sub-expressions"), + C(UNARY_MINUS_SUBEXPR, "Unary minus not supported in sub-expressions"), #undef C #define C(a, b) HIST_ERR_##a @@ -1672,10 +1671,6 @@ static int contains_operator(char *str, char **sep) */ minus_op = strrchr(str, '-'); if (minus_op) { - /* Unfortunately, the modifier ".sym-offset" can confuse things. */ - if (minus_op - str >= 4 && !strncmp(minus_op - 4, ".sym-offset", 11)) - goto out; - /* * Unary minus is not supported in sub-expressions. If * present, it is always the next root operator. @@ -2138,7 +2133,11 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, *flags |= HIST_FIELD_FL_HEX; else if (strcmp(modifier, "sym") == 0) *flags |= HIST_FIELD_FL_SYM; - else if (strcmp(modifier, "sym-offset") == 0) + /* + * 'sym-offset' occurrences in the trigger string are modified + * to 'symXoffset' to simplify arithmetic expression parsing. + */ + else if (strcmp(modifier, "symXoffset") == 0) *flags |= HIST_FIELD_FL_SYM_OFFSET; else if ((strcmp(modifier, "execname") == 0) && (strcmp(field_name, "common_pid") == 0)) @@ -2463,24 +2462,6 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, return ERR_PTR(-EINVAL); } - /* - * ".sym-offset" in expressions has no effect on their evaluation, - * but can confuse operator parsing. - */ - if (*n_subexprs == 0) { - sep = strstr(str, ".sym-offset"); - if (sep) { - *sep = '\0'; - if (strpbrk(str, "+-/*") || strpbrk(sep + 11, "+-/*")) { - *sep = '.'; - hist_err(file->tr, HIST_ERR_SYM_OFFSET_SUBEXPR, - errpos(sep)); - return ERR_PTR(-EINVAL); - } - *sep = '.'; - } - } - field_op = contains_operator(str, &sep); if (field_op == FIELD_OP_NONE) @@ -6004,7 +5985,7 @@ static int event_hist_trigger_func(struct event_command *cmd_ops, struct synth_event *se; const char *se_name; bool remove = false; - char *trigger, *p; + char *trigger, *p, *start; int ret = 0; lockdep_assert_held(&event_mutex); @@ -6052,6 +6033,16 @@ static int event_hist_trigger_func(struct event_command *cmd_ops, trigger = strstrip(trigger); } + /* + * To simplify arithmetic expression parsing, replace occurrences of + * '.sym-offset' modifier with '.symXoffset' + */ + start = strstr(trigger, ".sym-offset"); + while (start) { + *(start + 4) = 'X'; + start = strstr(start + 11, ".sym-offset"); + }; + attrs = parse_hist_trigger_attrs(file->tr, trigger); if (IS_ERR(attrs)) return PTR_ERR(attrs);