From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) (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 4A8E0320A00; Sat, 28 Mar 2026 02:30:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774665035; cv=none; b=gsmuHEfFjXHkiHIM9iPTHYw4lay5mCV5QckHRT6JuDX4qpYv2dON/5v/235zrVQS5OZPQ9ijk+PMbRjhlU1hZaj8/x6nVNaI3i3dKSLzU3sDY5XwMRbCbg5WXymrJKQZLgf2jm6dTPQSEtZm4mxpfcmSv7YgLO4H51wLydPWYuU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774665035; c=relaxed/simple; bh=YGJ/jhla2c2fCx7MkFmsZRgc90rphrVYBijnB4yfR6c=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jPkg8RJYabYz/QhTpMY9+aIIG3Vp9e3lGRD9LJ+dEcVXc0tffkinlTsqOa26cSq1cFbIRslsjILIPmhl9G+INrNApm+QPBIq5y0zGeepnieO8z9PVeeu853vVPmHuQh4ztHyd9SyYHJ6YhW9PVpzGZygRO8f+FiUTKCp4ts+dxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 45D9513CA74; Sat, 28 Mar 2026 02:30:26 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf19.hostedemail.com (Postfix) with ESMTPA id 4D91F20027; Sat, 28 Mar 2026 02:30:24 +0000 (UTC) Date: Fri, 27 Mar 2026 22:30:22 -0400 From: Steven Rostedt To: Wesley Atwell Cc: linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, mark.rutland@arm.com, mathieu.desnoyers@efficios.com, tom.zanussi@linux.intel.com Subject: Re: [PATCH v4 2/2] tracing: Drain deferred trigger frees if kthread creation fails Message-ID: <20260327223022.167defcc@robin> In-Reply-To: References: <20260324221326.1395799-1-atwellwea@gmail.com> <20260324221326.1395799-3-atwellwea@gmail.com> <20260327150634.5df3cf4f@gandalf.local.home> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; x86_64-redhat-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=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: 867prrxxakdgkryzye84g63gb81a9xr9 X-Rspamd-Server: rspamout04 X-Rspamd-Queue-Id: 4D91F20027 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+l3G1zDrIQ21CLa9jmjnHsd7OBfH6R1O8= X-HE-Tag: 1774665024-695282 X-HE-Meta: U2FsdGVkX1/glWykLMuTVzgg2sZfyEUHqVp8nvFHJiyYHM/zJZxWuYvIU1wfxagd7Cq1n8GZd9e3s3kA+4ni+s6ND2pO28jLPA4o98H6Auw7gHbUtMPA0zsAHUIFgHqw72oo0sdBZ0P+rFe/OMN2dP+nvN3i+vCM0c6KLbiqLbz8nLZcUZOB/wb9WWznz1WkIioQqi8a65lUqk1VxDtptkyDEtCltc7j+SmzyQcSrU+brqijAj0Ggt8ZtGkL365RNiHaOgkbvmgyEJQQNvcheks8XgmsN/60PGHw06JJWFiQU5gzNumuq4WiKVs2aS7+DczRyl0R6BKEmEbPa7oZ9EHax/DO7o9a On Fri, 27 Mar 2026 16:41:52 -0600 Wesley Atwell wrote: > Yes, > > This kernel command line reliably reaches trigger_data_free() during boot: > > trace_event=sched:sched_switch > trace_trigger=sched_switch.traceon,sched_switch.traceon > > On an unpatched tree, that crashes during early boot before userspace. > The call trace goes through: > > trigger_data_free() > __kthread_create_on_node() > try_to_wake_up() > > The stack also shows the boot-time trigger registration path: > > event_trigger_parse() > trigger_process_regex() > __trace_early_add_events() Thanks for this. I can reproduce the crash. I'm also going to add this to the change log as it is useful (I'll even add it to one of my regression tests). I'll take this patch separately (this didn't need to be a patch series, as the two patches do not depend on each other). -- Steve