From nobody Sun Feb 8 00:50:26 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 6F960176FDB; Wed, 27 Mar 2024 12:23:17 +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=1711542197; cv=none; b=OwmjKBc5JiPkHf+ft4oxnfxu4mTB6C1e2FDLBLQLRv9SwFBkn9N+HjmT/1NzAnoAhNBLnkFv7CzBZIAYRTxGH8SBXZFFcTUWlWFQO0aCv52ct7RSYDjrr1rj94GITFPfDbPXR4M+i/tCWwfOgS2YzUonmPUicVtOLoFERSWcfa8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711542197; c=relaxed/simple; bh=RwigAQmafhkqcfjzheZMcdBby7iXvnOAGJQb4topJtw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=G8+aDjljdElIbfEp8Sv0hjYON8B5r/VPTzrUkzkPZ192r7/a+KYK8F2LBJvYPCAG0NeWpm4VhvrqYRiTrqWCEN2tpDbhQgiWh7Bq7T+VGuUexiDTOAbZErT7U3k80ave8Leu5lr8AUhSlX//eTvcWdVSO3YqfcODt0ZPBHIMZKI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j39GwaqW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="j39GwaqW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 515E9C433F1; Wed, 27 Mar 2024 12:23:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711542197; bh=RwigAQmafhkqcfjzheZMcdBby7iXvnOAGJQb4topJtw=; h=From:To:Cc:Subject:Date:From; b=j39GwaqWNwuCMxbqBCeCZRzofWcJbM16RykA5LzgBd4FQuANjTrc0iH/uKXSUw5Yw P4QS9Jg8EPbZfnEDqp5lPanVH0Mr7grh+fzIBNOcmeQLxK6HGgSllikbwkR3EG+L7+ zjD2oVSw15ja8+QjYaa6IKjnoztOxFhCL7ZqEqS3CFZO/S3qhe+rvEVOKQtSzoDF+6 Th3isEn9BX2uvdKlHBc6wsRNYGyYYQNLNvvO6UME+TEXP5NyUvxHrkZIhiY1LHKMZL Zi0Ct9kRseG0/EwFhoia+2Uq6JO9RGZe6mkwmkV0jHzMk7RjE+Vx9ZMNHEAYQt+C6i E3vaC9Qw1EKaw== From: Sasha Levin To: stable@vger.kernel.org, rostedt@goodmis.org Cc: Mathieu Desnoyers , Masami Hiramatsu , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: FAILED: Patch "ring-buffer: Do not set shortest_full when full target is hit" failed to apply to 5.4-stable tree Date: Wed, 27 Mar 2024 08:23:15 -0400 Message-ID: <20240327122315.2838361-1-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . Thanks, Sasha Reviewed-by: Masami Hiramatsu (Google) ------------------ original commit in Linus's tree ------------------ From 761d9473e27f0c8782895013a3e7b52a37c8bcfc Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Tue, 12 Mar 2024 11:56:41 -0400 Subject: [PATCH] ring-buffer: Do not set shortest_full when full target is = hit The rb_watermark_hit() checks if the amount of data in the ring buffer is above the percentage level passed in by the "full" variable. If it is, it returns true. But it also sets the "shortest_full" field of the cpu_buffer that informs writers that it needs to call the irq_work if the amount of data on the ring buffer is above the requested amount. The rb_watermark_hit() always sets the shortest_full even if the amount in the ring buffer is what it wants. As it is not going to wait, because it has what it wants, there's no reason to set shortest_full. Link: https://lore.kernel.org/linux-trace-kernel/20240312115641.6aa8ba08@ga= ndalf.local.home Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Fixes: 42fb0a1e84ff5 ("tracing/ring-buffer: Have polling block on watermark= ") Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index aa332ace108b1..6ffbccb9bcf00 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -834,9 +834,10 @@ static bool rb_watermark_hit(struct trace_buffer *buff= er, int cpu, int full) pagebusy =3D cpu_buffer->reader_page =3D=3D cpu_buffer->commit_page; ret =3D !pagebusy && full_hit(buffer, cpu, full); =20 - if (!cpu_buffer->shortest_full || - cpu_buffer->shortest_full > full) - cpu_buffer->shortest_full =3D full; + if (!ret && (!cpu_buffer->shortest_full || + cpu_buffer->shortest_full > full)) { + cpu_buffer->shortest_full =3D full; + } raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); } return ret; --=20 2.43.0