From nobody Mon May 11 01:32:22 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6C9CC433EF for ; Tue, 19 Apr 2022 01:39:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233437AbiDSBmi (ORCPT ); Mon, 18 Apr 2022 21:42:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245693AbiDSBmf (ORCPT ); Mon, 18 Apr 2022 21:42:35 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 391FADE83 for ; Mon, 18 Apr 2022 18:39:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1650332394; x=1681868394; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=YTBlms3ZwknmerbjXMqn2HeZ2pfS/wcFLcEoslzwJhg=; b=iElDNwVgpvY/hlo+GOrIKy/uuYjPyoTeWqAAJw30+MB5GHx0lDffhO0S hTtyqkUx6JqYHUcatP1wtpkUMi1vzHSiXWay5ZBncBiD2xdfPN0GwFtxs V4YnxSoq62G9tr7nanK6hO4JG+O4ds3Ve4ewg6rBg4oMTSifvOLsw2xzH aPaFeAvPjLKNtmGGDsgBt8J/Xk2ucjgQxGUe/K1xPdnv8gNbDD4/9SMIj sLbSE9n6wpQpVadEiQ7PwXxrhXIYeREPw5McSEWpqMzjT1H3wDdFIR6Et vQugUqWvs0muJF9q3AvDh1K6Lmajg6ldJbogaCQf7VrTObdOcXNJGk6yw A==; X-IronPort-AV: E=McAfee;i="6400,9594,10321"; a="326549824" X-IronPort-AV: E=Sophos;i="5.90,271,1643702400"; d="scan'208";a="326549824" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Apr 2022 18:39:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,271,1643702400"; d="scan'208";a="657451325" Received: from ubuntu.bj.intel.com ([10.238.155.108]) by fmsmga002.fm.intel.com with ESMTP; 18 Apr 2022 18:39:52 -0700 From: Jun Miao To: rostedt@goodmis.org, mingo@redhat.com Cc: linux-kernel@vger.kernel.org, jun.miao@intel.com Subject: [PATCH] tracing: fix sleeping function called from invalid context on RT kernel Date: Tue, 19 Apr 2022 09:39:10 +0800 Message-Id: <20220419013910.894370-1-jun.miao@intel.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When setting bootparams=3D"trace_event=3Dinitcall:initcall_start tp_printk= =3D1" in the cmdline, the output_printk() was called, and the spin_lock_irqsave() was ca= lled in the atomic and irq disable interrupt context suitation. On the PREEMPT_RT kerne= l, these locks are replaced with sleepable rt-spinlock, so the stack calltrace= will be triggered. Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=3Dinitcall= :initcall_start tp_printk=3D1" enabled. BUG: sleeping function called from invalid context at kernel/locking/spinl= ock_rt.c:46 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0 preempt_count: 2, expected: 0 RCU nest depth: 0, expected: 0 Preemption disabled at: [] try_to_wake_up+0x7e/0xba0 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a8= 75f32bee7977f7367f9679ea7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01= /2014 Call Trace: dump_stack_lvl+0x60/0x8c dump_stack+0x10/0x12 __might_resched.cold+0x11d/0x155 rt_spin_lock+0x40/0x70 trace_event_buffer_commit+0x2fa/0x4c0 ? map_vsyscall+0x93/0x93 trace_event_raw_event_initcall_start+0xbe/0x110 ? perf_trace_initcall_finish+0x210/0x210 ? probe_sched_wakeup+0x34/0x40 ? ttwu_do_wakeup+0xda/0x310 ? trace_hardirqs_on+0x35/0x170 ? map_vsyscall+0x93/0x93 do_one_initcall+0x217/0x3c0 ? trace_event_raw_event_initcall_level+0x170/0x170 ? push_cpu_stop+0x400/0x400 ? cblist_init_generic+0x241/0x290 kernel_init_freeable+0x1ac/0x347 ? _raw_spin_unlock_irq+0x65/0x80 ? rest_init+0xf0/0xf0 kernel_init+0x1e/0x150 ret_from_fork+0x22/0x30 Signed-off-by: Jun Miao --- kernel/trace/trace.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 416496fefd56..26f945ac6c1a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2833,7 +2833,7 @@ trace_event_buffer_lock_reserve(struct trace_buffer *= *current_rb, } EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve); =20 -static DEFINE_SPINLOCK(tracepoint_iter_lock); +static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock); static DEFINE_MUTEX(tracepoint_printk_mutex); =20 static void output_printk(struct trace_event_buffer *fbuffer) @@ -2861,14 +2861,14 @@ static void output_printk(struct trace_event_buffer= *fbuffer) =20 event =3D &fbuffer->trace_file->event_call->event; =20 - spin_lock_irqsave(&tracepoint_iter_lock, flags); + raw_spin_lock_irqsave(&tracepoint_iter_lock, flags); trace_seq_init(&iter->seq); iter->ent =3D fbuffer->entry; event_call->event.funcs->trace(iter, 0, event); trace_seq_putc(&iter->seq, 0); printk("%s", iter->seq.buffer); =20 - spin_unlock_irqrestore(&tracepoint_iter_lock, flags); + raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags); } =20 int tracepoint_printk_sysctl(struct ctl_table *table, int write, --=20 2.32.0