multifd_send_pages() loops around the available channels,
the next channel to use between two calls to multifd_send_pages() is stored
inside a local static variable, next_channel.
It works well, except if the number of channels decreases between two calls
to multifd_send_pages(). In this case, the loop can try to access the
data of a channel that doesn't exist anymore.
The problem can be triggered if we start a migration with a given number of
channels and then we cancel the migration to restart it with a lower number.
This ends generally with an error like:
qemu-system-ppc64: .../util/qemu-thread-posix.c:77: qemu_mutex_lock_impl: Assertion `mutex->initialized' failed.
This patch fixes the error by capping next_channel with the current number
of channels before using it.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
migration/multifd.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/migration/multifd.c b/migration/multifd.c
index 5a3e4d0d46d1..d0441202aae9 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -415,6 +415,12 @@ static int multifd_send_pages(QEMUFile *f)
}
qemu_sem_wait(&multifd_send_state->channels_ready);
+ /*
+ * next_channel can remain from a previous migration that was
+ * using more channels, so ensure it doesn't overflow if the
+ * limit is lower now.
+ */
+ next_channel %= migrate_multifd_channels();
for (i = next_channel;; i = (i + 1) % migrate_multifd_channels()) {
p = &multifd_send_state->params[i];
--
2.26.2
Patchew URL: https://patchew.org/QEMU/20200617113154.593233-1-lvivier@redhat.com/
Hi,
This series failed the asan build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.
=== TEST SCRIPT BEGIN ===
#!/bin/bash
export ARCH=x86_64
make docker-image-fedora V=1 NETWORK=1
time make docker-test-debug@fedora TARGET_LIST=x86_64-softmmu J=14 NETWORK=1
=== TEST SCRIPT END ===
CC qga/commands.o
CC qga/guest-agent-command-state.o
CC qga/main.o
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
CC qga/commands-posix.o
CC qga/channel-posix.o
CC qga/qapi-generated/qga-qapi-visit.o
---
AR libvhost-user.a
GEN docs/interop/qemu-ga-ref.html
GEN docs/interop/qemu-ga-ref.txt
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
GEN docs/interop/qemu-ga-ref.7
AS pc-bios/optionrom/multiboot.o
CC pc-bios/optionrom/linuxboot_dma.o
---
SIGN pc-bios/optionrom/pvh.bin
LINK qemu-ga
LINK qemu-keymap
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
LINK ivshmem-client
LINK ivshmem-server
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
LINK qemu-nbd
LINK qemu-storage-daemon
LINK qemu-img
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
LINK qemu-io
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
LINK qemu-edid
LINK fsdev/virtfs-proxy-helper
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
LINK scsi/qemu-pr-helper
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
LINK qemu-bridge-helper
LINK virtiofsd
LINK vhost-user-input
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
/usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o)
GEN x86_64-softmmu/config-target.h
GEN x86_64-softmmu/hmp-commands-info.h
GEN x86_64-softmmu/hmp-commands.h
---
CC x86_64-softmmu/hw/rtc/mc146818rtc.o
CC x86_64-softmmu/hw/scsi/virtio-scsi.o
CC x86_64-softmmu/hw/scsi/virtio-scsi-dataplane.o
/tmp/qemu-test/src/fpu/softfloat.c:3365:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:3423:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~ ( ( (uint64_t) ( absZ1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:3483:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:3606:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x40 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:3760:13: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig &= ~ ( ( ( roundBits ^ 0x200 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:3987:21: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:4003:22: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig0 &= ~ ( ( (uint64_t) ( zSig1<<1 ) == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
/tmp/qemu-test/src/fpu/softfloat.c:4273:18: error: bitwise negation of a boolean expression; did you mean logical negation? [-Werror,-Wbool-operation]
zSig1 &= ~ ( ( zSig2 + zSig2 == 0 ) & roundNearestEven );
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!
8 errors generated.
make[1]: *** [/tmp/qemu-test/src/rules.mak:69: fpu/softfloat.o] Error 1
make[1]: *** Waiting for unfinished jobs....
CC x86_64-softmmu/hw/scsi/vhost-scsi-common.o
/tmp/qemu-test/src/migration/ram.c:919:45: error: implicit conversion from 'unsigned long' to 'double' changes value from 18446744073709551615 to 18446744073709551616 [-Werror,-Wimplicit-int-float-conversion]
xbzrle_counters.encoding_rate = UINT64_MAX;
~ ^~~~~~~~~~
/usr/include/stdint.h:130:23: note: expanded from macro 'UINT64_MAX'
---
18446744073709551615UL
^~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[1]: *** [/tmp/qemu-test/src/rules.mak:69: migration/ram.o] Error 1
make: *** [Makefile:527: x86_64-softmmu/all] Error 2
Traceback (most recent call last):
File "./tests/docker/docker.py", line 669, in <module>
sys.exit(main())
---
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run', '--label', 'com.qemu.instance.uuid=d52b42b055914f4fb4873ab613129c4b', '-u', '1003', '--security-opt', 'seccomp=unconfined', '--rm', '-e', 'TARGET_LIST=x86_64-softmmu', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e', 'SHOW_ENV=', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/home/patchew2/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-051us51k/src/docker-src.2020-06-17-08.15.43.22816:/var/tmp/qemu:z,ro', 'qemu:fedora', '/var/tmp/qemu/run', 'test-debug']' returned non-zero exit status 2.
filter=--filter=label=com.qemu.instance.uuid=d52b42b055914f4fb4873ab613129c4b
make[1]: *** [docker-run] Error 1
make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-051us51k/src'
make: *** [docker-run-test-debug@fedora] Error 2
real 4m27.275s
user 0m8.271s
The full log is available at
http://patchew.org/logs/20200617113154.593233-1-lvivier@redhat.com/testing.asan/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com
Laurent Vivier <lvivier@redhat.com> wrote: > multifd_send_pages() loops around the available channels, > the next channel to use between two calls to multifd_send_pages() is stored > inside a local static variable, next_channel. > > It works well, except if the number of channels decreases between two calls > to multifd_send_pages(). In this case, the loop can try to access the > data of a channel that doesn't exist anymore. > > The problem can be triggered if we start a migration with a given number of > channels and then we cancel the migration to restart it with a lower number. > This ends generally with an error like: > qemu-system-ppc64: .../util/qemu-thread-posix.c:77: qemu_mutex_lock_impl: Assertion `mutex->initialized' failed. > > This patch fixes the error by capping next_channel with the current number > of channels before using it. > > Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com>
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