From nobody Mon Feb 9 04:40:56 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0F62C13E7C5 for ; Wed, 6 Mar 2024 18:41:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709750510; cv=none; b=P/A1ABuMKsnklXwGoEMSOSlvjodTJDcHUR1f/n228Ab+KR5vZgP8lXxtkudaz6cMoQfNbsloe7pmG6+R/5kq4Dk0fe0BeYZIDs0Z7oNny/T89AtrdjPMo7gKmkOInywaCkNYG4qQeHRgr8uNh87P0VXP/joGbBzgCKEmjj/UPYs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709750510; c=relaxed/simple; bh=M32KOXv/AFVR6xfmKfYjkG0waeE8jfIiCibplogrfB4=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=gHHZipvNYuqWQbS+ZI6+9WoFI2by2g15n68C8TrRvKvOOABJGvVTYCz9vNivEoKYvVdc6g/231qKALbw7VDxicSYpvXp2kAbmXLkWFtBq1w+/66NRJKLjyw5GUPdq/dj6Yhw0NtNwhKs7qEvUNcpmz+yKXeJh71xndo4m74mR1M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFC45C43390; Wed, 6 Mar 2024 18:41:49 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rhwEw-00000000YAi-3uCp; Wed, 06 Mar 2024 13:43:42 -0500 Message-ID: <20240306184342.788071416@goodmis.org> User-Agent: quilt/0.67 Date: Wed, 06 Mar 2024 13:42:47 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Linus Torvalds Subject: [for-linus][PATCH 3/3] tracing: Limit trace_marker writes to just 4K References: <20240306184244.754263547@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Steven Rostedt (Google)" Limit the max print event of trace_marker to just 4K string size. This must also be less than the amount that can be held by a trace_seq along with the text that is before the output (like the task name, PID, CPU, state, etc). As trace_seq is made to handle large events (some greater than 4K). Make the max size of a trace_marker write event be 4K which is guaranteed to fit in the trace_seq buffer. Link: https://lore.kernel.org/linux-trace-kernel/20240304223433.4ba47dff@ga= ndalf.local.home Suggested-by: Linus Torvalds Reviewed-by: Mathieu Desnoyers Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 8198bfc54b58..d16b95ca58a7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7293,6 +7293,8 @@ tracing_free_buffer_release(struct inode *inode, stru= ct file *filp) return 0; } =20 +#define TRACE_MARKER_MAX_SIZE 4096 + static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) @@ -7320,6 +7322,9 @@ tracing_mark_write(struct file *filp, const char __us= er *ubuf, if ((ssize_t)cnt < 0) return -EINVAL; =20 + if (cnt > TRACE_MARKER_MAX_SIZE) + cnt =3D TRACE_MARKER_MAX_SIZE; + meta_size =3D sizeof(*entry) + 2; /* add '\0' and possible '\n' */ again: size =3D cnt + meta_size; @@ -7328,11 +7333,6 @@ tracing_mark_write(struct file *filp, const char __u= ser *ubuf, if (cnt < FAULTED_SIZE) size +=3D FAULTED_SIZE - cnt; =20 - if (size > TRACE_SEQ_BUFFER_SIZE) { - cnt -=3D size - TRACE_SEQ_BUFFER_SIZE; - goto again; - } - buffer =3D tr->array_buffer.buffer; event =3D __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, tracing_gen_ctx()); --=20 2.43.0