From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) (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 DFBC822B8B6; Wed, 8 Oct 2025 00:19:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759882772; cv=none; b=LzBDDJ1A0CRa/Miq2VvYN8872vPGsXHrKMItk4nV1NmY/CCyk/uk4h/dRAdRpm+kiOa5hj/VuyGkGM3Hv/dw0dNpCKhzggP9zzQ7rpvkm3oFG+rGon6oV4gTIZuj1p9lRG1c3vqCQxvU4gVKn+tXLhe3lG2qO/Xc/dIpV5RfYZc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759882772; c=relaxed/simple; bh=BN8cuSEBg66C2lF8YtmhtyuvN4mkZSwQNm7AYTmbIB0=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fmkqM95OLOVvgGdXJogNu1eci4Lq1tcNOT3jYgVq790JZNuM7O4WLBYT1UKMo2W8B0so+ZlhCD3pgM9LtnEeOFJKcraTyikHF4tSSUxt/YUgzmjVhfKK5fsMCv9fwGkVbUiX+4WnqLCyL9OwEMVqYVXefvTKS6K6iWh3eU+RZ/A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 3137FB8BB4; Wed, 8 Oct 2025 00:19:23 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf16.hostedemail.com (Postfix) with ESMTPA id 2C8D020016; Wed, 8 Oct 2025 00:19:21 +0000 (UTC) Date: Tue, 7 Oct 2025 20:21:13 -0400 From: Steven Rostedt To: Runping Lai Cc: Masami Hiramatsu , Mathieu Desnoyers , Wattson CI , kernel-team@android.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Luo Gengkun , Linus Torvalds Subject: Re: [PATCH v1] Revert "tracing: Fix tracing_marker may trigger page fault during preempt_disable" Message-ID: <20251007202113.1ce212a9@gandalf.local.home> In-Reply-To: References: <20251007003417.3470979-2-runpinglai@google.com> <20251006221043.07cdb0fd@gandalf.local.home> <20251007154308.5b158d04@gandalf.local.home> <20251007163141.1034b120@gandalf.local.home> <20251007174208.11fd02da@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspamout04 X-Rspamd-Queue-Id: 2C8D020016 X-Stat-Signature: rf5cg3xifex3t66bs9jw94qdiqjq6pbu X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX18Rc+590qhmKGx8oRxPsAh+DI/ZSCruAn8= X-HE-Tag: 1759882761-301618 X-HE-Meta: U2FsdGVkX19GlOxcxf6tQkRlJFy//VkzJRGPw+yeonaZjGjSxCkZNGrqaYnW7OkiliRr3vV4EWAzhhxMCTYJ2Kl4quFViXj8+IC0IVLevaIzctQ3GZPFwq7BUAyYIgTCksJgIXfbbrWSh8EXRqe8dLUlmRCtL/2XYrepW460cw1/2HnZuzP1vOl5CfKWxWjcSqqsEZk8hkPTmgUGc+dSRKnuVnfD6NW6NGMaHq4nMpkAC6YzblhL23pGt1OmeHheF2+zDq5pfwxGJABj+7mFG9+NQAq+WuBXRCvRhf50rn3ux9bOroiMx6+bEQUQWhtPJsVxKq29N1sRcsSBy1/U7g7o3Of81g85SvYfptJKiueTM5gh8+FhPG+67jcL/iXdIBW81v2XE4qG2TWQu6kflQ== On Tue, 7 Oct 2025 16:25:41 -0700 Runping Lai wrote: > On Tue, Oct 7, 2025 at 2:40=E2=80=AFPM Steven Rostedt wrote: > > > > On Tue, 7 Oct 2025 16:31:41 -0400 > > Steven Rostedt wrote: > > =20 > > > +static void trace_user_fault_buffer_free(struct trace_user_buf_info = *tinfo) > > > +{ > > > + char *buf; > > > + int cpu; > > > + > > > + for_each_possible_cpu(cpu) { > > > + buf =3D per_cpu_ptr(tinfo->tbuf, cpu)->buf; > > > + kfree(buf); > > > + } =20 > > > > Oops, missed: > > > > free_percpu(tinfo->tbuf); > > > > here. =20 >=20 > Hey Steve, >=20 > Thanks for providing the buffer-based solution. I tried it and it > fixes the problem! > However, the first experiment, adding pagefault_disable/enable() > around copy_nofault() > doesn't help. Still having the same problem. I suppose the issue is > more than pagefault? >=20 > Can you please suggest the next move? I can also do more tests if needed. >=20 I may need to make this patch the official solution. -- Steve