From nobody Mon Nov 25 18:52:48 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 E6E7821A4AE for ; Fri, 25 Oct 2024 15:12:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729869125; cv=none; b=sYIER5Sg3Aj9zYJh8wIFhnest8IyKfVLIa7gYhAR3An6LKe+un16xOHzoznzmUfas/9X1t/JDu+EzkNgHkJQiX0DYew2X8ZPCIcOSjRKgsEMYHGsfH6mIS9zsI66ujOV1t345exJjVNQjMCOtzxJIGdfAFJ0Kb9JLiHw8nolMYs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729869125; c=relaxed/simple; bh=16NCmAhjGQbw+/tIcvFYWrIt83TaD8/WL/KjPIqDzrc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bVQSxuwy0He1o5RpQg9BU1NoGHr1ARdH6uVWIh5ZsEl8dDwX7D2/yVLmbx10nMVFHyZjByRa0gd0mBNvBcjpBSZfL+tW9Di40NVWO8xE2MHQtbG+EEB8EDDppuVog5mlPLI6icYWnubEDF75ZGhbOZMi+noWIkRI4uNJu9fvCsw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=fgJhnSnE; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="fgJhnSnE" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729869121; 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: in-reply-to:in-reply-to:references:references; bh=VrMChLaTWQQV1P3cCXF0g4Mb1STd5YPEt4ibYFFJxW4=; b=fgJhnSnEQSTql4I4+FerEDjUXmI19VK+NxbhKXl3Hq6GJ/HQv1ipTufu8pTDSZv2RyjO2B WctAAgGWqxj+/xDsNihW+2AwG5llF5XDzMQS+8l8jTskh8afRSaXlhu0eUowl7xRdruy6a o2epJmpChMRnBbUAjXp/xWUjtESmFg0= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-35-oROdk647PWOwfbs1qWmB5g-1; Fri, 25 Oct 2024 11:11:58 -0400 X-MC-Unique: oROdk647PWOwfbs1qWmB5g-1 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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1D5A8193585B; Fri, 25 Oct 2024 15:11:53 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.22.65.27]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1F17D3000198; Fri, 25 Oct 2024 15:11:44 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, kexec@lists.infradead.org, David Hildenbrand , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Baoquan He , Vivek Goyal , Dave Young , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , Eric Farman , Andrew Morton Subject: [PATCH v1 01/11] fs/proc/vmcore: convert vmcore_cb_lock into vmcore_mutex Date: Fri, 25 Oct 2024 17:11:23 +0200 Message-ID: <20241025151134.1275575-2-david@redhat.com> In-Reply-To: <20241025151134.1275575-1-david@redhat.com> References: <20241025151134.1275575-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" We want to protect vmcore modifications from concurrent opening of the vmcore, and also serialize vmcore modiciations. Let's convert the spinlock into a mutex, because some of the operations we'll be protecting might sleep (e.g., memory allocations) and might take a bit longer. Signed-off-by: David Hildenbrand --- fs/proc/vmcore.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index b52d85f8ad59..110ce193d20f 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -62,7 +62,8 @@ core_param(novmcoredd, vmcoredd_disabled, bool, 0); /* Device Dump Size */ static size_t vmcoredd_orig_sz; =20 -static DEFINE_SPINLOCK(vmcore_cb_lock); +static DEFINE_MUTEX(vmcore_mutex); + DEFINE_STATIC_SRCU(vmcore_cb_srcu); /* List of registered vmcore callbacks. */ static LIST_HEAD(vmcore_cb_list); @@ -72,7 +73,7 @@ static bool vmcore_opened; void register_vmcore_cb(struct vmcore_cb *cb) { INIT_LIST_HEAD(&cb->next); - spin_lock(&vmcore_cb_lock); + mutex_lock(&vmcore_mutex); list_add_tail(&cb->next, &vmcore_cb_list); /* * Registering a vmcore callback after the vmcore was opened is @@ -80,13 +81,13 @@ void register_vmcore_cb(struct vmcore_cb *cb) */ if (vmcore_opened) pr_warn_once("Unexpected vmcore callback registration\n"); - spin_unlock(&vmcore_cb_lock); + mutex_unlock(&vmcore_mutex); } EXPORT_SYMBOL_GPL(register_vmcore_cb); =20 void unregister_vmcore_cb(struct vmcore_cb *cb) { - spin_lock(&vmcore_cb_lock); + mutex_lock(&vmcore_mutex); list_del_rcu(&cb->next); /* * Unregistering a vmcore callback after the vmcore was opened is @@ -95,7 +96,7 @@ void unregister_vmcore_cb(struct vmcore_cb *cb) */ if (vmcore_opened) pr_warn_once("Unexpected vmcore callback unregistration\n"); - spin_unlock(&vmcore_cb_lock); + mutex_unlock(&vmcore_mutex); =20 synchronize_srcu(&vmcore_cb_srcu); } @@ -120,9 +121,9 @@ static bool pfn_is_ram(unsigned long pfn) =20 static int open_vmcore(struct inode *inode, struct file *file) { - spin_lock(&vmcore_cb_lock); + mutex_lock(&vmcore_mutex); vmcore_opened =3D true; - spin_unlock(&vmcore_cb_lock); + mutex_unlock(&vmcore_mutex); =20 return 0; } --=20 2.46.1