From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F08313C9C4 for ; Wed, 29 Jul 2026 00:05:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785283530; cv=none; b=b5kwquGW5rvWcJn7ztVMHDMw0BR6JEMNho1YCjsb77rykjHViH1xb8vTDgAH9/ltJNS00DQQhaTln181gV2KwV4PqqwqfRJyoTAkxbGL+A3OxCbimPI8GF7Vo0VxSMosp4hHItJ5aovd7mHSIJ0Xbvkeq9lem4k9mqUIJfO0RU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785283530; c=relaxed/simple; bh=HStlXrHy8YHd0XkWHuhJcsuwdYt8TTam5neFbhFw3PM=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=nMBNsoGAc06U1/5IEXs2Wq1R9myLFHVOObsaoHyJ7bnEXwPZSDwzBzJT9p8dvCJtfGG4xJ+LJtK2UZU4D122vDtJ5pYL4VBm1caV9E1bxPjpdKTvsYfAkxb+oJE0mm1rvkwT1jKPZHKSeg/RXdapu8xZuMOk18FPPkqfaqpG3Gs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P1mGat+1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P1mGat+1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17C5E1F0155C; Wed, 29 Jul 2026 00:05:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785283523; bh=5Z5JnXQtnHWSzvS+eju7zGk5IeI0109bYswGREhj808=; h=Date:From:To:Cc:Subject:References; b=P1mGat+1R0hujrGKnlRCNEH4xtT+al+4ck/TYdf9s9i1fdk6ENqUnmuaxulanPs0q dkKn06bQocCrULrPjNEfmgMJeIHoiN4pcPXaAl/9PFWrFfFIshFx1dgzw7eoJndF6k fQUY8gg/Q+3foLFOXbdVkY1RYHylTBWJfGIDnx+QgYH/36QhQKAWKWJl2/1Yth100K sb54uqZz1Q0sddfoAh55PWiG+BpvKrF/TZqb0HzVKzjp/jlDehloIsLK2yI6gTckHg YE2t1fErhE21rmv6j/bW835rIoluKyV0Uif47bS+bbxOn6y1A5rQGdhjkFLK3VgNxV WIxKHoOiMFpRg== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1woro5-00000006Uhg-3CRQ; Tue, 28 Jul 2026 20:05:57 -0400 Message-ID: <20260729000557.641743825@kernel.org> User-Agent: quilt/0.69 Date: Tue, 28 Jul 2026 20:05:39 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Woradorn Laodhanadhaworn Subject: [for-next][PATCH 16/16] tracing: Use seq_buf for string concatenation References: <20260729000523.093060274@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Woradorn Laodhanadhaworn In preparation for removing the strlcat API[1], replace the string concatenation logic with a struct seq_buf, which tracks the current position and the remaining space internally. Use seq_buf_str() to NUL-terminate before passing to early_enable_events(). Link: https://github.com/KSPP/linux/issues/370 [1] Link: https://patch.msgid.link/20260713045249.69942-1-woradorn.laon@gmail.com Signed-off-by: Woradorn Laodhanadhaworn [ Moved placement of #include ] Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 714285e23a2e..a8590d2394e3 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -4604,13 +4605,20 @@ extern struct trace_event_call *__start_ftrace_events[]; extern struct trace_event_call *__stop_ftrace_events[]; static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata; +static struct seq_buf bootup_event_seq __initdata = { + .buffer = bootup_event_buf, + .size = sizeof(bootup_event_buf), +}; static __init int setup_trace_event(char *str) { - if (bootup_event_buf[0] != '\0') - strlcat(bootup_event_buf, ",", COMMAND_LINE_SIZE); + if (seq_buf_used(&bootup_event_seq) > 0) + seq_buf_puts(&bootup_event_seq, ","); + + seq_buf_puts(&bootup_event_seq, str); - strlcat(bootup_event_buf, str, COMMAND_LINE_SIZE); + if (seq_buf_has_overflowed(&bootup_event_seq)) + return -ENOMEM; trace_set_ring_buffer_expanded(NULL); disable_tracing_selftest("running event tracing"); @@ -4869,6 +4877,7 @@ static __init int event_trace_enable(void) */ __trace_early_add_events(tr); + seq_buf_str(&bootup_event_seq); early_enable_events(tr, bootup_event_buf, false); trace_printk_start_comm(); @@ -4897,6 +4906,7 @@ static __init int event_trace_enable_again(void) if (!tr) return -ENODEV; + seq_buf_str(&bootup_event_seq); early_enable_events(tr, bootup_event_buf, true); return 0; -- 2.53.0