From nobody Thu Dec 18 05:32:11 2025 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C3FB41A9FB8 for ; Tue, 7 Oct 2025 00:35:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759797358; cv=none; b=FQzG58psGnhWcHa82w7DbBA/Dc56YRET1pAgKsmrhlSfBfllKSJ4Zm/dYdK/8CpA95DaNvxhV3gngtroP5THYZeJnPjLgpMKcjWIRmbGpZ8MqoX0yEDXw9ASaywvPWA7yNC8Y98cYljrAFk+Rbq9oUCxnUBWVARXzjzx/jtPHwM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759797358; c=relaxed/simple; bh=eaYVbAhT4lR/ZZ5Jro1HbUESdMb7AvVKpDnCTSt+6g8=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=se1fuvE+W32Ewua2EYuwZVaADnucS3DAfo6g8GZFfaTobZrh9O9v1svKDwQLqh1sf2Sj9UpK0LLZVfyafbcixjr7tv4TuZJCmuSiBZijq3TArH3mTZ8Yv4rM7Z0t+cc87BfJAfnGx8nJM1/FxCEplrtxNEJIOLzDGOjZQtLJSy8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--runpinglai.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=vOO0yupP; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--runpinglai.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vOO0yupP" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2711a55da20so34174285ad.1 for ; Mon, 06 Oct 2025 17:35:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1759797356; x=1760402156; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=Y6HSIAmMJUhDqfzrB/fS5/kaQRYPRIDkYIlVlDXHnEY=; b=vOO0yupPgSf8x/G82WTBytGAtwDlFEcwxaMKzjZf+tykD1yE9LqICuSeXdoVUcp7bT lJLNHMSbS9S+KXY2jUqv3JmHPfqN/2qtD3TKMHwydv1yZaQzgiUVyZdC0z6pWGoAjNZC lzTrTKyNhUfDdHjKVeDgdKapx6TE8HqIL6PhfnvVTIOQqNyIpJIkzDWCWFoaWYwsmudV OTRvAV0kbNK7MXhrzRbNmHo0pLRnQbSA7dtRl/q7XtMoohqPGfkcCnNl4m4gxlsdlSAp BsFVUNYZcC/CywEb3iBvthTs5FFKzdmQAnURVcAth+PppETMegLEhMWR9iZ77uBsR2gN BRtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759797356; x=1760402156; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=Y6HSIAmMJUhDqfzrB/fS5/kaQRYPRIDkYIlVlDXHnEY=; b=WqT+rEdkHGLDvNUJjrhEKc3mVirqLaYp1HtKJrr0YCb07jbEbZFU2OfjtMxwr998L0 N7Mg4/3vPopemdxGWWrqLY6tirtuwWwWMPYvbxczO1EAZC2dP62cvchj9w+vtufYoV+G UcELsZT2fdCBF+vv9+KtyyEckpTCyJj0VfVj5omHXctQXYuGetCHGo3k4v2ymqSX65MS 7QprxE0rYB1nhwb40EXeM+i9V45bzDSjnRg6TN8rq5zkdtjuzuWGFs7P5dQjMSj2wpL1 3+dYDclRJ164Xa7uMXZLCswlc5DhMa5LHGjaN1wjl0FFJA6LH+cqs2rmccVRkM1sO9em UW3w== X-Forwarded-Encrypted: i=1; AJvYcCXpFabcq5w1/WVM1/Q6LXO1ih5KlaLQg6KmuYABYHtMtJUrPg43snnVBJYf72+mEqlZiZ1T90HAEDfJyVc=@vger.kernel.org X-Gm-Message-State: AOJu0YyAfiP47f4uoF0drbs3hlW7P0cVtCZ4+xvinYDH+cQoWJmnNrQ/ KXDzx4r7/LbTr/pqDiIk3Gxd5HYxp7YP6vDrz9nRO3izcwQSbw3CVVWl8nMyaNKKD3Xtsvwf2/1 bLzF8QGPIOVDR7OhuWGyMpQ== X-Google-Smtp-Source: AGHT+IGrHmHhj30VeewmLKDwaHhCJ86g6aH0nKGtqdD2dWGpbW474Z1gxjM8uvB35pCImQIRal7TzTHgTluIfL0A X-Received: from plhy5.prod.google.com ([2002:a17:902:d645:b0:264:d7d1:2748]) (user=runpinglai job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:1b4f:b0:28e:8c3a:fb02 with SMTP id d9443c01a7336-28e9a566888mr176712275ad.14.1759797356148; Mon, 06 Oct 2025 17:35:56 -0700 (PDT) Date: Tue, 7 Oct 2025 00:34:17 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.51.0.618.g983fd99d29-goog Message-ID: <20251007003417.3470979-2-runpinglai@google.com> Subject: [PATCH v1] Revert "tracing: Fix tracing_marker may trigger page fault during preempt_disable" From: Runping Lai To: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers Cc: Runping Lai , Wattson CI , kernel-team@android.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This reverts commit 3d62ab32df065e4a7797204a918f6489ddb8a237. It's observed on Pixel 6 that this commit causes a severe functional regression: all user-space writes to trace_marker now fail. The write does not goes through at all. The error is observed in the shell as 'printf: write: Bad address'. This breaks a primary ftrace interface for user-space debugging and profiling. In kernel trace file, it's logged as 'tracing_mark_write: '. After reverting this commit, functionality is restored. Signed-off-by: Runping Lai Reported-by: Wattson CI Tested-by: Runping Lai --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 156e7e0bf559..bb9a6284a629 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7213,7 +7213,7 @@ static ssize_t write_marker_to_buffer(struct trace_ar= ray *tr, const char __user entry =3D ring_buffer_event_data(event); entry->ip =3D ip; =20 - len =3D copy_from_user_nofault(&entry->buf, ubuf, cnt); + len =3D __copy_from_user_inatomic(&entry->buf, ubuf, cnt); if (len) { memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); cnt =3D FAULTED_SIZE; @@ -7310,7 +7310,7 @@ static ssize_t write_raw_marker_to_buffer(struct trac= e_array *tr, =20 entry =3D ring_buffer_event_data(event); =20 - len =3D copy_from_user_nofault(&entry->id, ubuf, cnt); + len =3D __copy_from_user_inatomic(&entry->id, ubuf, cnt); if (len) { entry->id =3D -1; memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); --=20 2.51.0.618.g983fd99d29-goog