From mboxrd@z Thu Jan 1 00:00:00 1970 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 0ADABC761A6 for ; Tue, 28 Mar 2023 09:39:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232256AbjC1Jjq (ORCPT ); Tue, 28 Mar 2023 05:39:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230434AbjC1Jjo (ORCPT ); Tue, 28 Mar 2023 05:39:44 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3750155A4 for ; Tue, 28 Mar 2023 02:39:30 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id E8C561F8BA; Tue, 28 Mar 2023 09:39:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1679996368; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=UgfE83B87JnzYkBplYgpUKueaTqClGbainLz0Z27234=; b=gfW4yDUUcpChSDwKbNwRwXDijsOrfTAYRLllKADw1zl14hMfdZIMuXN3TbT4u6uaSFrDqT Q2vFJQRYFbG8AjjFNyNEcn651PsaOqFI97MLfmMww8FlBy070mZdJ/W+m/I5+RASiIcqQa vOUS4k4u/p/h3gEUPsirmtaOOyp2Jec= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id B4D771390B; Tue, 28 Mar 2023 09:39:28 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 7X7MKtC1ImS8TgAAMHmgww (envelope-from ); Tue, 28 Mar 2023 09:39:28 +0000 From: Juergen Gross To: linux-kernel@vger.kernel.org Cc: Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , xen-devel@lists.xenproject.org, Dan Carpenter Subject: [PATCH] xen/pvcalls: don't call bind_evtchn_to_irqhandler() under lock Date: Tue, 28 Mar 2023 11:39:24 +0200 Message-Id: <20230328093924.12260-1-jgross@suse.com> X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org bind_evtchn_to_irqhandler() shouldn't be called under spinlock, as it can sleep. This requires to move the calls of create_active() out of the locked regions. This is no problem, as the worst which could happen would be a spurious call of the interrupt handler, causing a spurious wake_up(). Reported-by: Dan Carpenter Link: https://lore.kernel.org/lkml/Y+JUIl64UDmdkboh@kadam/ Signed-off-by: Juergen Gross --- drivers/xen/pvcalls-front.c | 46 ++++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 19 deletions(-) diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index d5d589bda243..6e5d712e3115 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -227,22 +227,31 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id) static void free_active_ring(struct sock_mapping *map); -static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, - struct sock_mapping *map) +static void pvcalls_front_destroy_active(struct pvcalls_bedata *bedata, + struct sock_mapping *map) { int i; unbind_from_irqhandler(map->active.irq, map); - spin_lock(&bedata->socket_lock); - if (!list_empty(&map->list)) - list_del_init(&map->list); - spin_unlock(&bedata->socket_lock); + if (bedata) { + spin_lock(&bedata->socket_lock); + if (!list_empty(&map->list)) + list_del_init(&map->list); + spin_unlock(&bedata->socket_lock); + } for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) gnttab_end_foreign_access(map->active.ring->ref[i], NULL); gnttab_end_foreign_access(map->active.ref, NULL); + free_active_ring(map); +} + +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, + struct sock_mapping *map) +{ + pvcalls_front_destroy_active(bedata, map); kfree(map); } @@ -433,19 +442,18 @@ int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr, pvcalls_exit_sock(sock); return ret; } - - spin_lock(&bedata->socket_lock); - ret = get_request(bedata, &req_id); + ret = create_active(map, &evtchn); if (ret < 0) { - spin_unlock(&bedata->socket_lock); free_active_ring(map); pvcalls_exit_sock(sock); return ret; } - ret = create_active(map, &evtchn); + + spin_lock(&bedata->socket_lock); + ret = get_request(bedata, &req_id); if (ret < 0) { spin_unlock(&bedata->socket_lock); - free_active_ring(map); + pvcalls_front_destroy_active(NULL, map); pvcalls_exit_sock(sock); return ret; } @@ -821,28 +829,28 @@ int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags) pvcalls_exit_sock(sock); return ret; } - spin_lock(&bedata->socket_lock); - ret = get_request(bedata, &req_id); + ret = create_active(map2, &evtchn); if (ret < 0) { + free_active_ring(map2); + kfree(map2); clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); spin_unlock(&bedata->socket_lock); - free_active_ring(map2); - kfree(map2); pvcalls_exit_sock(sock); return ret; } - ret = create_active(map2, &evtchn); + spin_lock(&bedata->socket_lock); + ret = get_request(bedata, &req_id); if (ret < 0) { - free_active_ring(map2); - kfree(map2); clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags); spin_unlock(&bedata->socket_lock); + pvcalls_front_free_map(bedata, map2); pvcalls_exit_sock(sock); return ret; } + list_add_tail(&map2->list, &bedata->socket_mappings); req = RING_GET_REQUEST(&bedata->ring, req_id); -- 2.35.3