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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 56906C4167B for ; Wed, 29 Nov 2023 12:53:06 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r8K2u-0005rn-JY; Wed, 29 Nov 2023 07:52:04 -0500 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 1r8K2q-0005rY-LS for qemu-devel@nongnu.org; Wed, 29 Nov 2023 07:52:00 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r8K2n-0006gA-QX for qemu-devel@nongnu.org; Wed, 29 Nov 2023 07:51:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701262316; 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=7m8iFpi+sdzw01gp5zF7Z/Lrd1jJaM05alWBgvRanWM=; b=KJp64A/YBLA64jze8b9mOb4t3xFu9onxfx9cLd9ilbSIBhqUfDJvXhXJLa8lYXEUtTG8Ki +GOxItaCaVcRWpqr/RzE6BEN2808s8n/IgwRSqkiHQ2RrZKMACFTiIZDxWng3cdJe62GJT nC6j1CCW41e1ck1iJG5TLLci23G4eSc= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-356-rF8l087fOXyGKm0HL10GBA-1; Wed, 29 Nov 2023 07:51:52 -0500 X-MC-Unique: rF8l087fOXyGKm0HL10GBA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 067EE28088A8; Wed, 29 Nov 2023 12:51:52 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.148]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A1D675028; Wed, 29 Nov 2023 12:51:51 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id AEFD021E6A1F; Wed, 29 Nov 2023 13:51:50 +0100 (CET) From: Markus Armbruster To: Het Gala Cc: qemu-devel@nongnu.org, prerna.saxena@nutanix.com, quintela@redhat.com, berrange@redhat.com, peter.maydell@linaro.org, farosas@suse.de Subject: Re: [PATCH v3] migration: free 'channel' after its use in migration.c References: <20231129080624.161578-1-het.gala@nutanix.com> Date: Wed, 29 Nov 2023 13:51:50 +0100 In-Reply-To: <20231129080624.161578-1-het.gala@nutanix.com> (Het Gala's message of "Wed, 29 Nov 2023 08:06:24 +0000") Message-ID: <87fs0ok9i1.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org I'ld like to suggest a clearer subject: migration: Plug memory leak with migration URIs Het Gala writes: > 'channel' in qmp_migrate() and qmp_migrate_incoming() is not > auto-freed. migrate_uri_parse() allocates memory to 'channel' if Not sure we need the first sentence. QMP commands never free their arguments. > the user opts for old syntax - uri, which is leaked because there > is no code for freeing 'channel'. > So, free channel to avoid memory leak in case where 'channels' > is empty and uri parsing is required. > Fixes: 5994024f ("migration: Implement MigrateChannelList to qmp > migration flow") > > Signed-off-by: Het Gala > Suggested-by: Markus Armbruster Keep the Fixes: tag on a single line, and next to the other tags: [...] is empty and uri parsing is required. Fixes: 5994024f ("migration: Implement MigrateChannelList to qmp migration flow") Signed-off-by: Het Gala Suggested-by: Markus Armbruster > --- > migration/migration.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/migration/migration.c b/migration/migration.c > index 28a34c9068..34340f3440 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -515,7 +515,7 @@ static void qemu_start_incoming_migration(const char *uri, bool has_channels, > MigrationChannelList *channels, > Error **errp) > { > - MigrationChannel *channel = NULL; > + g_autoptr(MigrationChannel) channel = NULL; > MigrationAddress *addr = NULL; > MigrationIncomingState *mis = migration_incoming_get_current(); > > @@ -533,18 +533,18 @@ static void qemu_start_incoming_migration(const char *uri, bool has_channels, > error_setg(errp, "Channel list has more than one entries"); > return; > } > - channel = channels->value; > + addr = channels->value->addr; > } else if (uri) { > /* caller uses the old URI syntax */ > if (!migrate_uri_parse(uri, &channel, errp)) { > return; > } > + addr = channel->addr; > } else { > error_setg(errp, "neither 'uri' or 'channels' argument are " > "specified in 'migrate-incoming' qmp command "); > return; > } > - addr = channel->addr; > > /* transport mechanism not suitable for migration? */ > if (!migration_channels_and_transport_compatible(addr, errp)) { > @@ -1932,7 +1932,7 @@ void qmp_migrate(const char *uri, bool has_channels, > bool resume_requested; > Error *local_err = NULL; > MigrationState *s = migrate_get_current(); > - MigrationChannel *channel = NULL; > + g_autoptr(MigrationChannel) channel = NULL; > MigrationAddress *addr = NULL; > > /* > @@ -1949,18 +1949,18 @@ void qmp_migrate(const char *uri, bool has_channels, > error_setg(errp, "Channel list has more than one entries"); > return; > } > - channel = channels->value; > + addr = channels->value->addr; > } else if (uri) { > /* caller uses the old URI syntax */ > if (!migrate_uri_parse(uri, &channel, errp)) { > return; > } > + addr = channel->addr; > } else { > error_setg(errp, "neither 'uri' or 'channels' argument are " > "specified in 'migrate' qmp command "); > return; > } > - addr = channel->addr; > > /* transport mechanism not suitable for migration? */ > if (!migration_channels_and_transport_compatible(addr, errp)) { I tested this with an --enable-santizers build. Before the patch: $ qemu-system-x86_64 -nodefaults -S -display none -monitor stdio -incoming unix:123 ==3260873==WARNING: ASan doesn't fully support makecontext/swapcontext functions and may produce false positives in some cases! QEMU 8.1.92 monitor - type 'help' for more information (qemu) q ================================================================= ==3260873==ERROR: LeakSanitizer: detected memory leaks Direct leak of 40 byte(s) in 1 object(s) allocated from: #0 0x7f0ba08ba097 in calloc (/lib64/libasan.so.8+0xba097) #1 0x7f0b9f4eb5b0 in g_malloc0 (/lib64/libglib-2.0.so.0+0x5f5b0) #2 0x55b446454dbe in migrate_uri_parse ../migration/migration.c:490 #3 0x55b4464557c9 in qemu_start_incoming_migration ../migration/migration.c:539 #4 0x55b446461687 in qmp_migrate_incoming ../migration/migration.c:1734 #5 0x55b4463df1c2 in qmp_x_exit_preconfig ../system/vl.c:2718 #6 0x55b4463e4d8e in qemu_init ../system/vl.c:3753 #7 0x55b446f63ca9 in main ../system/main.c:47 #8 0x7f0b9d04a54f in __libc_start_call_main (/lib64/libc.so.6+0x2754f) Direct leak of 16 byte(s) in 1 object(s) allocated from: #0 0x7f0ba08ba097 in calloc (/lib64/libasan.so.8+0xba097) #1 0x7f0b9f4eb5b0 in g_malloc0 (/lib64/libglib-2.0.so.0+0x5f5b0) #2 0x55b4464557c9 in qemu_start_incoming_migration ../migration/migration.c:539 #3 0x55b446461687 in qmp_migrate_incoming ../migration/migration.c:1734 #4 0x55b4463df1c2 in qmp_x_exit_preconfig ../system/vl.c:2718 #5 0x55b4463e4d8e in qemu_init ../system/vl.c:3753 #6 0x55b446f63ca9 in main ../system/main.c:47 #7 0x7f0b9d04a54f in __libc_start_call_main (/lib64/libc.so.6+0x2754f) Direct leak of 8 byte(s) in 1 object(s) allocated from: #0 0x7f0ba08bb1a8 in operator new(unsigned long) (/lib64/libasan.so.8+0xbb1a8) #1 0x7f0b9a9255b7 in _sub_I_65535_0.0 (/lib64/libtcmalloc_minimal.so.4+0xe5b7) Indirect leak of 48 byte(s) in 1 object(s) allocated from: #0 0x7f0ba08ba097 in calloc (/lib64/libasan.so.8+0xba097) #1 0x7f0b9f4eb5b0 in g_malloc0 (/lib64/libglib-2.0.so.0+0x5f5b0) #2 0x55b4464557c9 in qemu_start_incoming_migration ../migration/migration.c:539 #3 0x55b446461687 in qmp_migrate_incoming ../migration/migration.c:1734 #4 0x55b4463df1c2 in qmp_x_exit_preconfig ../system/vl.c:2718 #5 0x55b4463e4d8e in qemu_init ../system/vl.c:3753 #6 0x55b446f63ca9 in main ../system/main.c:47 #7 0x7f0b9d04a54f in __libc_start_call_main (/lib64/libc.so.6+0x2754f) Indirect leak of 4 byte(s) in 1 object(s) allocated from: #0 0x7f0ba08ba6af in __interceptor_malloc (/lib64/libasan.so.8+0xba6af) #1 0x7f0b9f4eb128 in g_malloc (/lib64/libglib-2.0.so.0+0x5f128) SUMMARY: AddressSanitizer: 116 byte(s) leaked in 5 allocation(s). Afterwards: ==3260526==WARNING: ASan doesn't fully support makecontext/swapcontext functions and may produce false positives in some cases! QEMU 8.1.92 monitor - type 'help' for more information (qemu) q ================================================================= ==3260526==ERROR: LeakSanitizer: detected memory leaks Direct leak of 40 byte(s) in 1 object(s) allocated from: #0 0x7f97e54ba097 in calloc (/lib64/libasan.so.8+0xba097) #1 0x7f97e41c75b0 in g_malloc0 (/lib64/libglib-2.0.so.0+0x5f5b0) #2 0x55ae31b02dbe in migrate_uri_parse ../migration/migration.c:490 #3 0x55ae31b0382c in qemu_start_incoming_migration ../migration/migration.c:539 #4 0x55ae31b0f724 in qmp_migrate_incoming ../migration/migration.c:1734 #5 0x55ae31a8d1c2 in qmp_x_exit_preconfig ../system/vl.c:2718 #6 0x55ae31a92d8e in qemu_init ../system/vl.c:3753 #7 0x55ae32611de2 in main ../system/main.c:47 #8 0x7f97e1c4a54f in __libc_start_call_main (/lib64/libc.so.6+0x2754f) Direct leak of 8 byte(s) in 1 object(s) allocated from: #0 0x7f97e54bb1a8 in operator new(unsigned long) (/lib64/libasan.so.8+0xbb1a8) #1 0x7f97df6055b7 in _sub_I_65535_0.0 (/lib64/libtcmalloc_minimal.so.4+0xe5b7) SUMMARY: AddressSanitizer: 48 byte(s) leaked in 2 allocation(s). This confirms the patch succeeds at plugging leaks the -incoming path. It also shows there's one left in migrate_uri_parse(): bool migrate_uri_parse(const char *uri, MigrationChannel **channel, Error **errp) { g_autoptr(MigrationChannel) val = g_new0(MigrationChannel, 1); g_autoptr(MigrationAddress) addr = g_new0(MigrationAddress, 1); SocketAddress *saddr = NULL; Useless initializer. InetSocketAddress *isock = &addr->u.rdma; strList **tail = &addr->u.exec.args; if (strstart(uri, "exec:", NULL)) { addr->transport = MIGRATION_ADDRESS_TYPE_EXEC; #ifdef WIN32 QAPI_LIST_APPEND(tail, g_strdup(exec_get_cmd_path())); QAPI_LIST_APPEND(tail, g_strdup("/c")); #else QAPI_LIST_APPEND(tail, g_strdup("/bin/sh")); QAPI_LIST_APPEND(tail, g_strdup("-c")); #endif QAPI_LIST_APPEND(tail, g_strdup(uri + strlen("exec:"))); } else if (strstart(uri, "rdma:", NULL)) { if (inet_parse(isock, uri + strlen("rdma:"), errp)) { qapi_free_InetSocketAddress(isock); return false; } addr->transport = MIGRATION_ADDRESS_TYPE_RDMA; } else if (strstart(uri, "tcp:", NULL) || strstart(uri, "unix:", NULL) || strstart(uri, "vsock:", NULL) || strstart(uri, "fd:", NULL)) { Aside: indentation is off. addr->transport = MIGRATION_ADDRESS_TYPE_SOCKET; saddr = socket_parse(uri, errp); @saddr allocated. if (!saddr) { return false; } addr->u.socket.type = saddr->type; addr->u.socket.u = saddr->u; Members of @saddr copied into @addr. } else if (strstart(uri, "file:", NULL)) { addr->transport = MIGRATION_ADDRESS_TYPE_FILE; addr->u.file.filename = g_strdup(uri + strlen("file:")); if (file_parse_offset(addr->u.file.filename, &addr->u.file.offset, errp)) { return false; } } else { error_setg(errp, "unknown migration protocol: %s", uri); return false; } val->channel_type = MIGRATION_CHANNEL_TYPE_MAIN; val->addr = g_steal_pointer(&addr); *channel = g_steal_pointer(&val); @saddr leaked. return true; } Obvious fix: g_free(saddr) right after copying its members. Another fix: make @saddr g_autofree, and keep the initializer. Separate patch. Would you like to take care of it? This one, preferably with the commit message improved: Tested-by: Markus Armbruster Reviewed-by: Markus Armbruster