From patchwork Fri Aug 11 15:08:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabiano Rosas X-Patchwork-Id: 1820315 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=t8vx8ShN; dkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=I3E5xfud; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RMnJS62nwz1yf6 for ; Sat, 12 Aug 2023 01:09:28 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qUTl5-0000ba-DB; Fri, 11 Aug 2023 11:09:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qUTkz-0000Zs-9w for qemu-devel@nongnu.org; Fri, 11 Aug 2023 11:08:53 -0400 Received: from smtp-out1.suse.de ([2001:67c:2178:6::1c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qUTkv-0006Hu-3k for qemu-devel@nongnu.org; Fri, 11 Aug 2023 11:08:51 -0400 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-out1.suse.de (Postfix) with ESMTPS id CE7B62188D; Fri, 11 Aug 2023 15:08:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1691766527; 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: in-reply-to:in-reply-to:references:references; bh=TGQOHZA1EOlvWg+cTrtICJk/oIlwUWTaoHqhgAIgHuE=; b=t8vx8ShN4dS+OUzU4cVi1tvRwEx1J23jGljol5fvTyMr5zDIncmUnUYddtTfGApUOlgahM cd+xxsqYSQ1Des9gHiXOcuvhTSoUvvG4AN7I3LxEVziVEF9UfbvOCG2BGJfjLTacSMnJsw uGDUziFeaVtgFrAW5UDjAZAvGtq5Bx8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1691766527; 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: in-reply-to:in-reply-to:references:references; bh=TGQOHZA1EOlvWg+cTrtICJk/oIlwUWTaoHqhgAIgHuE=; b=I3E5xfudieMG3Th5S5nkqgq3SFSvyCtrHsOGq4n8VyaaEonjMoa1S3a3+MDc6YQnk822u8 Zo2JLyXthOhdTSAg== 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 4D3BB13592; Fri, 11 Aug 2023 15:08:46 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 4GpPBv5O1mS7KwAAMHmgww (envelope-from ); Fri, 11 Aug 2023 15:08:46 +0000 From: Fabiano Rosas To: qemu-devel@nongnu.org Cc: Juan Quintela , Peter Xu , Wei Wang , Leonardo Bras Subject: [PATCH v3 04/10] migration: Fix possible race when shutting down to_dst_file Date: Fri, 11 Aug 2023 12:08:30 -0300 Message-Id: <20230811150836.2895-5-farosas@suse.de> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20230811150836.2895-1-farosas@suse.de> References: <20230811150836.2895-1-farosas@suse.de> MIME-Version: 1.0 Received-SPF: pass client-ip=2001:67c:2178:6::1c; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org It's not safe to call qemu_file_shutdown() on the to_dst_file without first checking for the file's presence under the lock. The cleanup of this file happens at postcopy_pause() and migrate_fd_cleanup() which are not necessarily running in the same thread as migrate_fd_cancel(). Signed-off-by: Fabiano Rosas Reviewed-by: Peter Xu --- migration/migration.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index 85c171f32c..5e6a766235 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1245,7 +1245,7 @@ static void migrate_fd_error(MigrationState *s, const Error *error) static void migrate_fd_cancel(MigrationState *s) { int old_state ; - QEMUFile *f = migrate_get_current()->to_dst_file; + trace_migrate_fd_cancel(); WITH_QEMU_LOCK_GUARD(&s->qemu_file_lock) { @@ -1271,11 +1271,13 @@ static void migrate_fd_cancel(MigrationState *s) * If we're unlucky the migration code might be stuck somewhere in a * send/write while the network has failed and is waiting to timeout; * if we've got shutdown(2) available then we can force it to quit. - * The outgoing qemu file gets closed in migrate_fd_cleanup that is - * called in a bh, so there is no race against this cancel. */ - if (s->state == MIGRATION_STATUS_CANCELLING && f) { - qemu_file_shutdown(f); + if (s->state == MIGRATION_STATUS_CANCELLING) { + WITH_QEMU_LOCK_GUARD(&s->qemu_file_lock) { + if (s->to_dst_file) { + qemu_file_shutdown(s->to_dst_file); + } + } } if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) { Error *local_err = NULL; @@ -1519,12 +1521,14 @@ void qmp_migrate_pause(Error **errp) { MigrationState *ms = migrate_get_current(); MigrationIncomingState *mis = migration_incoming_get_current(); - int ret; + int ret = 0; if (ms->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) { /* Source side, during postcopy */ qemu_mutex_lock(&ms->qemu_file_lock); - ret = qemu_file_shutdown(ms->to_dst_file); + if (ms->to_dst_file) { + ret = qemu_file_shutdown(ms->to_dst_file); + } qemu_mutex_unlock(&ms->qemu_file_lock); if (ret) { error_setg(errp, "Failed to pause source migration");