On 29/11/23 6:21 pm, Markus Armbruster wrote:
I'ld like to suggest a clearer subject:
migration: Plug memory leak with migration URIs
Ack. Will update the commit message
Het Gala<het.g...@nutanix.com> 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.
Ack.
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<het.g...@nutanix.com>
Suggested-by: Markus Armbruster<arm...@redhat.com>
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<het.g...@nutanix.com>
Suggested-by: Markus Armbruster<arm...@redhat.com>
Ack.
[...]
+ 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).
curious: how to get this stack trace ? I tried to configure and build
qemu with --enable-santizers option, but on running the tests 'make -j
test', I see:
==226453==LeakSanitizer has encountered a fatal error. ==226453==HINT:
For debugging, try setting environment variable
LSAN_OPTIONS=verbosity=1:log_threads=1 ==226453==HINT: LeakSanitizer
does not work under ptrace (strace, gdb, etc)
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,
[...]
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<arm...@redhat.com>
Reviewed-by: Markus Armbruster<arm...@redhat.com>
Fabiano has already answered to your query.
Regards,
Het Gala
