From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cstnet.cn (smtp25.cstnet.cn [159.226.251.25]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF9431E2614; Thu, 23 Apr 2026 22:46:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.25 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776984374; cv=none; b=Q79TclazDLRbTojfi97+EzEArNMDip1sC59hiEq8a1POEr1H8UaV84K2eklSI0fnlwLUwuuSYVuLfVg2vCb1f4qMK5t+9wIHCAM+2V4/RugGUTdHa2msxzVChBf22G6FWiNMWVLASHBQ6s3y/GM9KET8RZTcDS8VIdf5Cd7FNoo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776984374; c=relaxed/simple; bh=zaszI8Yj4d70OjMC0e5OL1kGxYADmIlnzFl1cY3sinQ=; h=From:Date:Message-ID:To:Cc:Subject:In-Reply-To:References; b=sSCFG+ecf3SOuUx7tunyHq5UksfkpE9gE0E44o4kd9q3KaZACChTKOhzmtxtDFlRIDSs7icnzCqy0Mwmjhf6by7zNy3KNsdtyDA6dBbcExGVZ9N/0YdIU/IGC9IYdf2W+wvkWMAUGM308OyuPXMkbqGzQC8wB7UHjySCQqwKV7w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from 04-tracing-synth-v5.eml (unknown [111.196.245.116]) by APP-05 (Coremail) with SMTP id zQCowAAnfhEqoepp33lsDg--.9914S2; Fri, 24 Apr 2026 06:46:02 +0800 (CST) From: Pengpeng Hou Date: Thu, 23 Apr 2026 23:33:00 +0800 Message-ID: <20260424070104.1-tracing-synth-v5-pengpeng@iscas.ac.cn> To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , Tom Zanussi , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, pengpeng@iscas.ac.cn Subject: [PATCH v5] tracing: Bound synthetic-field strings with seq_buf In-Reply-To: <20260417223001.1-tracing-synth-v4-pengpeng@iscas.ac.cn> References: <20260329030950.32503-2-pengpeng@iscas.ac.cn> <20260401112224.85582-2-pengpeng@iscas.ac.cn> <20260409103001.1-tracing-hist-synth-v3-pengpeng@iscas.ac.cn> <20260417223001.1-tracing-synth-v4-pengpeng@iscas.ac.cn> X-CM-TRANSID:zQCowAAnfhEqoepp33lsDg--.9914S2 X-Coremail-Antispam: 1UD129KBjvJXoWxZF1UJryxArWUXFW8tr4DXFb_yoWrGryUpF WrAw4DG398Jr42gr4fCF4qkr95Aw4kur1qgF4Yk3yktr13tr4v93yq9ry5JasYqrWI9wsx WF4qgrZ8CwsrZFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvK14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2jI8I6cxK6x804I0_JFv_Gryl8cAvFVAK0II2c7 xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE 2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVWxJr0_GcWl84ACjc xK6I8E87Iv6xkF7I0E14v26F4UJVW0owAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40E FcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUXVWUAwAv7VC2z280aVAFwI0_Jr 0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JM4x0x7Aq67IIx4CEVc8vx2IE rcIFxwCY1x0262kKe7AKxVWUAVWUtwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbV WUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF 67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42 IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF 0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxh VjvjDU0xZFpf9x0JUQo7NUUUUU= X-CM-SenderInfo: pshqw1xhqjqxpvfd2hldfou0/ Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The synthetic field helpers build a prefixed synthetic variable name and a generated hist command in fixed MAX_FILTER_STR_VAL buffers. The current code appends those strings with raw strcat(), so long key lists, field names, or saved filters can run past the end of the staging buffers. Build both strings with seq_buf and propagate -E2BIG if either the synthetic variable name or the generated command exceeds MAX_FILTER_STR_VAL. This keeps the existing tracing-side limit while using the helper intended for bounded command construction. Fixes: 02205a6752f2 ("tracing: Add support for 'field variables'") Signed-off-by: Pengpeng Hou --- Changes since v4: - add the requested blank lines around seq_buf_str() comments - add the seq_buf_str() comment for the generated command buffer too - keep saved_filter scoped next to its point of use diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 0dbbf6cca9bc..87429567417f 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -2968,14 +2969,24 @@ find_synthetic_field_var(struct hist_trigger_data *target_hist_data, char *system, char *event_name, char *field_name) { struct hist_field *event_var; + struct seq_buf s; char *synthetic_name; synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL); if (!synthetic_name) return ERR_PTR(-ENOMEM); - strcpy(synthetic_name, "synthetic_"); - strcat(synthetic_name, field_name); + seq_buf_init(&s, synthetic_name, MAX_FILTER_STR_VAL); + seq_buf_puts(&s, "synthetic_"); + seq_buf_puts(&s, field_name); + + /* Terminate synthetic_name with a NUL. */ + seq_buf_str(&s); + + if (seq_buf_has_overflowed(&s)) { + kfree(synthetic_name); + return ERR_PTR(-E2BIG); + } event_var = find_event_var(target_hist_data, system, event_name, synthetic_name); @@ -3020,7 +3031,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data, struct trace_event_file *file; struct hist_field *key_field; struct hist_field *event_var; - char *saved_filter; + struct seq_buf s; char *cmd; int ret; @@ -3065,28 +3076,37 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data, return ERR_PTR(-ENOMEM); } + seq_buf_init(&s, cmd, MAX_FILTER_STR_VAL); + /* Use the same keys as the compatible histogram */ - strcat(cmd, "keys="); + seq_buf_puts(&s, "keys="); for_each_hist_key_field(i, hist_data) { key_field = hist_data->fields[i]; if (!first) - strcat(cmd, ","); - strcat(cmd, key_field->field->name); + seq_buf_putc(&s, ','); + seq_buf_puts(&s, key_field->field->name); first = false; } /* Create the synthetic field variable specification */ - strcat(cmd, ":synthetic_"); - strcat(cmd, field_name); - strcat(cmd, "="); - strcat(cmd, field_name); + seq_buf_printf(&s, ":synthetic_%s=%s", field_name, field_name); /* Use the same filter as the compatible histogram */ - saved_filter = find_trigger_filter(hist_data, file); - if (saved_filter) { - strcat(cmd, " if "); - strcat(cmd, saved_filter); + { + char *saved_filter = find_trigger_filter(hist_data, file); + + if (saved_filter) + seq_buf_printf(&s, " if %s", saved_filter); + } + + /* Terminate cmd with a NUL. */ + seq_buf_str(&s); + + if (seq_buf_has_overflowed(&s)) { + kfree(cmd); + kfree(var_hist); + return ERR_PTR(-E2BIG); } var_hist->cmd = kstrdup(cmd, GFP_KERNEL); -- 2.50.1 (Apple Git-155)