From nobody Fri Dec 19 17:15:18 2025 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 B3AE2634E1 for ; Thu, 21 Dec 2023 16:10:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 522E4C433CA; Thu, 21 Dec 2023 16:10:01 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rGLdZ-000000041L3-1Jnc; Thu, 21 Dec 2023 11:11:05 -0500 Message-ID: <20231221161105.083563911@goodmis.org> User-Agent: quilt/0.67 Date: Thu, 21 Dec 2023 11:10:34 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Tzvetomir Stoyanov , Vincent Donnefort , Kent Overstreet Subject: [for-next][PATCH 10/16] tracing: Stop the tracing while changing the ring buffer subbuf size References: <20231221161024.478795180@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)" Because the main buffer and the snapshot buffer need to be the same for some tracers, otherwise it will fail and disable all tracing, the tracers need to be stopped while updating the sub buffer sizes so that the tracers see the main and snapshot buffers with the same sub buffer size. Link: https://lore.kernel.org/linux-trace-kernel/20231219185630.353222794@g= oodmis.org Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Tzvetomir Stoyanov Cc: Vincent Donnefort Cc: Kent Overstreet Fixes: 2808e31ec12e ("ring-buffer: Add interface for configuring trace sub = buffer size") Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2439e00aa4ce..82303bd2bba1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9412,13 +9412,16 @@ buffer_order_write(struct file *filp, const char __= user *ubuf, if (val < 0 || val > 7) return -EINVAL; =20 + /* Do not allow tracing while changing the order of the ring buffer */ + tracing_stop_tr(tr); + old_order =3D ring_buffer_subbuf_order_get(tr->array_buffer.buffer); if (old_order =3D=3D val) - return 0; + goto out; =20 ret =3D ring_buffer_subbuf_order_set(tr->array_buffer.buffer, val); if (ret) - return 0; + goto out; =20 #ifdef CONFIG_TRACER_MAX_TRACE =20 @@ -9445,11 +9448,15 @@ buffer_order_write(struct file *filp, const char __= user *ubuf, */ tracing_disabled =3D 1; } - return ret; + goto out; } out_max: #endif (*ppos)++; + out: + if (ret) + cnt =3D ret; + tracing_start_tr(tr); return cnt; } =20 --=20 2.42.0