I'ld like to suggest a clearer subject: migration: Plug memory leak with migration URIs
Het Gala <[email protected]> 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 <[email protected]> > Suggested-by: Markus Armbruster <[email protected]> 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 <[email protected]> Suggested-by: Markus Armbruster <[email protected]> > --- > 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 <[email protected]> Reviewed-by: Markus Armbruster <[email protected]>
