From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) (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 ECD0A2EC553; Mon, 9 Mar 2026 20:02:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773086581; cv=none; b=V4Yq8zpOcu1TS8cff9lpQipZ9KmZa8dfHnNz1vGHQiwJZaSZHf0LJxgbWxRrSJrsRKZWamIxSXoKM2gRgv92fxgIsSP1oMC1UCVbuT1SdJTZ2AcX8m9ZOXVET9vNnnK7EPKq6pqEI33Db0yhiNmdxYHzf4yaFdHNGkLNcXwCmMM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773086581; c=relaxed/simple; bh=4QRGyVduG/Qaz1BCew/1ZmaegZ9qxUUkfCV8AiwOovM=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Pgdas72iDTdhFdGbqPfahyA766LuYQXo1xWBe/u5woEKZMFZh/8eyh12CTk4PEx0auaMLyGep1VUaztoDNS3PaSwTpqcF+hrklFkg7H2xFHoTxheNotT2X26JBjUybrUCCd+k4754P7CF1Nt14LKbJB1+aUMEHwhua+4csrmOKg= 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=216.40.44.14 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 omf10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 1DED41B73DB; Mon, 9 Mar 2026 20:02:53 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf10.hostedemail.com (Postfix) with ESMTPA id 3F85732; Mon, 9 Mar 2026 20:02:51 +0000 (UTC) Date: Mon, 9 Mar 2026 16:02:59 -0400 From: Steven Rostedt To: Wesley Atwell Cc: mhiramat@kernel.org, mark.rutland@arm.com, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] tracing: drain deferred trigger frees if kthread startup fails Message-ID: <20260309160259.0c94958f@gandalf.local.home> In-Reply-To: <20260309195220.2726094-2-atwellwea@gmail.com> References: <20260309195220.2726094-1-atwellwea@gmail.com> <20260309195220.2726094-2-atwellwea@gmail.com> 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=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: h4atcd7r5un6eu8imnkcypk9zif9nkky X-Rspamd-Server: rspamout04 X-Rspamd-Queue-Id: 3F85732 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+rLF9KddfVKdVBrlutGLRigU5G6F1DZ6A= X-HE-Tag: 1773086571-473091 X-HE-Meta: U2FsdGVkX19RfQ+rFssaj0yqED4Bn6OGGqEZUxUvGSgZjcKt5lwxr+Iblrh8SV97gBUYDmtS7UkVcBBSxWwg0D8CqoT8488G7bnKgWmsXOkHsdAcpFHzDTc/wjEmnStf61TfjVVrZJ0Ks+t4Scbt+mviCy7/fSeqh50mJIsJXFXPjVoqA8+AJN2zVMW2o9dajwZnwCKil34QEisQIjex+y7qtGuqCybIvXuOp0kVxn/L4BKRJzx4k6pmhE5IVFmppyMsv32tgQzi1L1yySL4Fczk0CSOY6jQGYr+SdiJkShO/AjoQWdrmz2Ff9agQ6Iq28r4oN42+FQ7ybUsKnDkIkYEV7K68o+R On Mon, 9 Mar 2026 13:52:20 -0600 Wesley Atwell wrote: > @@ -56,30 +89,48 @@ void trigger_data_free(struct event_trigger_data *data) > if (data->cmd_ops->set_filter) > data->cmd_ops->set_filter(NULL, data, NULL); > > + /* > + * Boot-time trigger registration can fail before kthread creation > + * works. Keep the deferred-free semantics during boot and let late > + * init start the kthread to drain the list. > + */ > + if (system_state == SYSTEM_BOOTING && !trigger_kthread) { > + llist_add(&data->llist, &trigger_data_free_list); > + return; > + } > + > if (unlikely(!trigger_kthread)) { > guard(mutex)(&trigger_data_kthread_mutex); > - /* Check again after taking mutex */ > - if (!trigger_kthread) { > - struct task_struct *kthread; > > - kthread = kthread_create(trigger_kthread_fn, NULL, > - "trigger_data_free"); > - if (!IS_ERR(kthread)) > - WRITE_ONCE(trigger_kthread, kthread); > + trigger_start_kthread_locked(); > + if (!trigger_kthread) { > + llist_add(&data->llist, &trigger_data_free_list); > + trigger_data_free_queued_locked(); > + return; > } > } > > - if (!trigger_kthread) { > - /* Do it the slow way */ You removed the above comment. It's still relevant in the above if statement. -- Steve > - tracepoint_synchronize_unregister(); > - kfree(data); > - return; > - } > - > llist_add(&data->llis