From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 75F2A30B51F for ; Tue, 2 Dec 2025 09:20:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764667256; cv=none; b=q421I2PNES642aFzoZ2euo13UMI1ULxutHYEa8JmLqocsxLdKJB1LGx8IUyfbMoYF5vXkDj7yU9SdbOSorjZPlWOw59LpRh5HWxIZSAHESEtlNzsnkw2K6OqoVRYbcja1wgBb0WPJVv3eH4kXCIF8kN1DRWjV8Te9WRlwfOV5Nk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764667256; c=relaxed/simple; bh=vH4vWkh7gbGhbWgaAEhQ1uS1OHOgO3gnXLvxNqqIsZ0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RXkucUEiF4qA90LdR5tHWUnsYmXWVndHIQdVs98C1fvKFabWczRUmaQgHoD5HMulCAGavdkPSjxO8qytWAtPeHH4iETxhMy92W1qmQNih3J+DVB878GJsxh9EyALmOHGTsGSIYoDMs3zENCIDZqs0w44kL3Xp/yvKF6bTmxCBmA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=LsFVFyVo; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LsFVFyVo" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764667254; 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: in-reply-to:in-reply-to:references:references; bh=fU8QCiuksw8tBhDpNDpp9KqQoaz5so+HUSNROIQdK5o=; b=LsFVFyVo7ipDIKBYNTlFvrsmBm1y6fPa8K50z5NX42U/zG/19yQdZ+7qPvaST+041ONb5M z37uFONhazeIFuhDqaUcHGogyqnqGKUA5wyuMj0vGiIZJ9xRIPBNQAK3bTswoGagTU3TeG Be0cVzHEHAU8xR+nEKSOlS+c/KcjJZQ= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-524-VSlh5EwTOjGhsljq3MbErw-1; Tue, 02 Dec 2025 04:20:49 -0500 X-MC-Unique: VSlh5EwTOjGhsljq3MbErw-1 X-Mimecast-MFC-AGG-ID: VSlh5EwTOjGhsljq3MbErw_1764667248 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BD7B71800250; Tue, 2 Dec 2025 09:20:47 +0000 (UTC) Received: from fedora (unknown [10.72.116.20]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E98A130001A4; Tue, 2 Dec 2025 09:20:42 +0000 (UTC) Date: Tue, 2 Dec 2025 17:20:32 +0800 From: Ming Lei To: Cong Zhang Cc: Jens Axboe , Daniel Wagner , Hannes Reinecke , linux-arm-msm@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, pavan.kondeti@oss.qualcomm.com Subject: Re: [PATCH] blk-mq: Abort suspend when wakeup events are pending Message-ID: References: <20251202-blkmq_skip_waiting-v1-1-f73d8a977ce0@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251202-blkmq_skip_waiting-v1-1-f73d8a977ce0@oss.qualcomm.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On Tue, Dec 02, 2025 at 11:56:12AM +0800, Cong Zhang wrote: > During system suspend, wakeup capable IRQs for block device can be > delayed, which can cause blk_mq_hctx_notify_offline() to hang > indefinitely while waiting for pending request to complete. > Skip the request waiting loop and abort suspend when wakeup events are > pending to prevent the deadlock. > > Fixes: bf0beec0607d ("blk-mq: drain I/O when all CPUs in a hctx are offline") > Signed-off-by: Cong Zhang > --- > The issue was found during system suspend with a no_soft_reset > virtio-blk device. Here is the detailed analysis: > - When system suspend starts and no_soft_reset is enabled, virtio-blk > does not call its suspend callback. > - Some requests are dispatched and queued. After sending the virtqueue > notifier, the kernel waits for an IRQ to complete the request. > - The virtio-blk IRQ is wakeup-capable. When the IRQ is triggered, it > remains pending because the device is in the suspend process. Can you explain a bit for above point? Why does the IRQ remains pending and not get handled? Thanks, Ming