From nobody Mon Apr 6 04:57:29 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 AC155C6FA82 for ; Sat, 10 Sep 2022 22:30:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229787AbiIJWa6 (ORCPT ); Sat, 10 Sep 2022 18:30:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230385AbiIJW3k (ORCPT ); Sat, 10 Sep 2022 18:29:40 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C61145F6B for ; Sat, 10 Sep 2022 15:28:19 -0700 (PDT) Message-ID: <20220910222302.052398226@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1662848897; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=PfOqpESp8tLtZDC+o8o6mnQEU5nU5UN8jXbbOmj7yS4=; b=m6Abpy6h1kF4rVeB+tpgtOq5St2HvOoeyZmg3+oUoEtc765WcnPNdjjdDskblrqvvh5HNk KiRC42PRB7VaAGyui0U3PPmaJ2HA4GU41PDgVaIDtcov1VV3AfkKdlLog5LOMIinhHX0jQ QzXs+yLhpaAHDcVD7saCgOBVUKYcjwAgW9Jt3p/yX2MuRk2oM7hRX4+sDJsxzVP1Og4wFG LGm+QnND9C0++XeX14/sd8bJqLKt1FbOmKPMGoqBXo3ZpqRWoPrRf/FTmo4N1so5lSKl8E yvQQq1ppEUsHjPnfshWShiM/PP40N03NHcxpGJW/C3jDOtofdbkHIzVEvj+CfA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1662848897; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=PfOqpESp8tLtZDC+o8o6mnQEU5nU5UN8jXbbOmj7yS4=; b=XSgI0HWlYJEj+zBs/+PztE9DWGK8iwwPJ6EA+zl/UFDLvCDcC9P9LSHOe29UE+vTNZxvAz 2L3mmKMAyxEIB+CA== From: Thomas Gleixner To: LKML Cc: John Ogness , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Linus Torvalds , Peter Zijlstra , "Paul E. McKenney" , Daniel Vetter , Greg Kroah-Hartman , Helge Deller , Jason Wessel , Daniel Thompson , John Ogness Subject: [patch RFC 29/29] printk: Add atomic write enforcement to warn/panic... References: <20220910221947.171557773@linutronix.de> MIME-Version: 1.0 Date: Sun, 11 Sep 2022 00:28:17 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Signed-off-by: John Ogness Invoke the atomic write enforcement functions for warn/panic to ensure that the information gets out to the consoles. This is not yet a final solution as this still unlocks consoles and depends on the "reliablity" of legacy consoles which are invoked during printk(). Once the legacy is converted over this can be changed to lock consoles on entry, print undisturbed and release them on exit. Signed-off-by: John Ogness Signed-off-by: Thomas Gleixner --- kernel/panic.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/kernel/panic.c +++ b/kernel/panic.c @@ -256,6 +256,12 @@ void panic(const char *fmt, ...) if (old_cpu !=3D PANIC_CPU_INVALID && old_cpu !=3D this_cpu) panic_smp_self_stop(); =20 + /* + * No point in saving the previous printk severity level + * here. Panic won't come back + */ + cons_atomic_enter(CONS_PRIO_PANIC); + console_verbose(); bust_spinlocks(1); va_start(args, fmt); @@ -602,6 +608,10 @@ struct warn_args { void __warn(const char *file, int line, void *caller, unsigned taint, struct pt_regs *regs, struct warn_args *args) { + enum cons_prio prev_prio; + + prev_prio =3D cons_atomic_enter(CONS_PRIO_EMERGENCY); + disable_trace_on_warning(); =20 if (file) @@ -633,6 +643,8 @@ void __warn(const char *file, int line, =20 /* Just a warning, don't kill lockdep. */ add_taint(taint, LOCKDEP_STILL_OK); + + cons_atomic_exit(CONS_PRIO_EMERGENCY, prev_prio); } =20 #ifndef __WARN_FLAGS