From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 19D65371880; Fri, 28 Aug 2026 15:58:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787932696; cv=none; b=aUOeyrId5kdxiXSUWE/pcr62Ic3jpI9uZMXYVkeUHvWpS1x0SD49gtjkd4nnq+Cqt9nbWsqAu5s2GoQgMXyeVuq53EEzyEBClIDcDl6P85UVXr9rWaa4CZCTud753F+9FZj3JnCdQbnwjM/Nord2KQ1X3iGBWu4Xrfrjlw7CDxA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787932696; c=relaxed/simple; bh=LbR0znRzRfTh41Qv63K7WCKvumr+27ShRRjRn+x07XM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=tZcmT2pd6OGcXtFlBNnjfz5ELvh4TnAdFANQq4RmQ1a0rPpf+0LKfcublZiOy4bMZSd9NAei3olKUSpmVsKUb9bRjAID5cXVGbG4xrCyVGnIE0I26inyCKqHO6lq5Ml7lo+BHPGgVCei4Y15nZfByz67WDvrjJJXwrR8RnIu/q4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=vgr9CwGF; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=9ZKqs/sY; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="vgr9CwGF"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="9ZKqs/sY" From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1787932692; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=JPqDNKwChZDP342Usda3rhXvIiQJ79oFJiWvu8RCDfs=; b=vgr9CwGFwIpbZ3tRYFS2Q1oWvi1gg0ZmIIumv845hUKj6VOmsd0XqwMSqr+UP2dRdkDrP7 ueLX52oBedFeESloBN6CvppQMU9CXIFVtN8+02FXHbdPHOClrhKZ4rEw60dgK5xRglqIrk 448FSL+FwojzxRnXCRnZ3eDKNUzUL9Yi1o3BnbGWePv2zDOYCh59BM2RSSGh3iXHqkS1OD Hd+KldjJfWHxP6xb6rq8rsAyDqc0ZGJjxA4EvwcYTt69fVj6D17gCWjaFUsBVp8SJOtRaD L7x1ZWDGCFDypmDWip3tHGFcPySpH7WVRrvuHVkHRh8aicvEjAs8uLj9KMDGJA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1787932692; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=JPqDNKwChZDP342Usda3rhXvIiQJ79oFJiWvu8RCDfs=; b=9ZKqs/sY+4yXeseYqQX9V6otfoW63uvuR3CmzbgqFuO5VzBNiWtZFo0MHXsEm8bhZCHLrs R/orb+uBMeRcDQDQ== To: "Greg Kroah-Hartman" , Jiri Slaby Cc: Andy Shevchenko , Petr Mladek , Sebastian Andrzej Siewior , Jon Hunter , Thierry Reding , linux-kernel@vger.kernel.org, =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Andy Shevchenko , Crescent Hsieh , Hugo Villeneuve , linux-serial@vger.kernel.org Subject: [PATCH tty 0/1] Make 8250 deferred MSR handling LAZY Date: Fri, 28 Aug 2026 18:04:07 +0206 Message-ID: <20260828155811.270462-1-john.ogness@linutronix.de> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit There was a report and follow-up discussion [0] about a problem using regular irq_work queuing on some platforms when entering cpuidle. To circumvent this problem, all irq_work for printk will become IRQ_WORK_LAZY [1]. The 8250 console driver uses irq_work to defer MSR handling during atomic printing. This means it is vulnerable to the same problem if, for example, a WARN() is hit while entering cpuidle on one of the affected platforms. Avoid the problem for deferred MSR handling by changing console_msr_work to IRQ_WORK_LAZY. [0] https://lore.kernel.org/lkml/f3757a75-0ba1-4558-bf57-f19ab7e59a4c@nvidia.com [1] https://lore.kernel.org/lkml/20260828140218.232439-1-john.ogness@linutronix.de John Ogness (1): serial: 8250: Change console_msr_work to IRQ_WORK_LAZY drivers/tty/serial/8250/8250_port.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) base-commit: 45c13f3f9e3bb15fd89ff2864c6f627a3b4b4229 -- 2.47.3