New QEMU savevm version #15
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This sounds good to me, but we should make sure we have a way of migrating existing replays to the new savevm format. |
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Working on a system where snapshots use QEMU v3 format and recordings use panda v4 format. V4 works in panda already. |
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phulin
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Feb 6, 2017
QEMU will crash with the follow backtrace if the new created thread exited before we call qemu_thread_set_name() for it. (gdb) bt #0 0x00007f9a68b095d7 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56 #1 0x00007f9a68b0acc8 in __GI_abort () at abort.c:90 #2 0x00007f9a69cda389 in PAT_abort () from /usr/lib64/libuvpuserhotfix.so #3 0x00007f9a69cdda0d in patchIllInsHandler () from /usr/lib64/libuvpuserhotfix.so #4 <signal handler called> #5 pthread_setname_np (th=140298470549248, name=name@entry=0x8cc74a "io-task-worker") at ../nptl/sysdeps/unix/sysv/linux/pthread_setname.c:49 #6 0x00000000007f5f20 in qemu_thread_set_name (thread=thread@entry=0x7ffd2ac09680, name=name@entry=0x8cc74a "io-task-worker") at util/qemu_thread_posix.c:459 #7 0x00000000007f679e in qemu_thread_create (thread=thread@entry=0x7ffd2ac09680, name=name@entry=0x8cc74a "io-task-worker",start_routine=start_routine@entry=0x7c1300 <qio_task_thread_worker>, arg=arg@entry=0x7f99b8001720, mode=mode@entry=1) at util/qemu_thread_posix.c:498 #8 0x00000000007c15b6 in qio_task_run_in_thread (task=task@entry=0x7f99b80033d0, worker=worker@entry=0x7bd920 <qio_channel_socket_connect_worker>, opaque=0x7f99b8003370, destroy=0x7c6220 <qapi_free_SocketAddress>) at io/task.c:133 #9 0x00000000007bda04 in qio_channel_socket_connect_async (ioc=0x7f99b80014c0, addr=0x37235d0, callback=callback@entry=0x54ad00 <qemu_chr_socket_connected>, opaque=opaque@entry=0x38118b0, destroy=destroy@entry=0x0) at io/channel_socket.c:191 #10 0x00000000005487f6 in socket_reconnect_timeout (opaque=0x38118b0) at qemu_char.c:4402 #11 0x00007f9a6a1533b3 in g_timeout_dispatch () from /usr/lib64/libglib-2.0.so.0 #12 0x00007f9a6a15299a in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0 #13 0x0000000000747386 in glib_pollfds_poll () at main_loop.c:227 #14 0x0000000000747424 in os_host_main_loop_wait (timeout=404000000) at main_loop.c:272 #15 0x0000000000747575 in main_loop_wait (nonblocking=nonblocking@entry=0) at main_loop.c:520 #16 0x0000000000557d31 in main_loop () at vl.c:2170 #17 0x000000000041c8b7 in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:5083 Let's detach the new thread after calling qemu_thread_set_name(). Signed-off-by: Caoxinhua <caoxinhua@huawei.com> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Message-Id: <1483493521-9604-1-git-send-email-zhang.zhanghailiang@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
phulin
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Feb 6, 2017
AioHandlers marked ->is_external must be skipped when aio_node_check() fails. bdrv_drained_begin() needs this to prevent dataplane from submitting new I/O requests while another thread accesses the device and relies on it being quiesced. This patch fixes the following segfault: Program terminated with signal SIGSEGV, Segmentation fault. #0 0x00005577f6127dad in bdrv_io_plug (bs=0x5577f7ae52f0) at qemu/block/io.c:2650 2650 bdrv_io_plug(child->bs); [Current thread is 1 (Thread 0x7ff5c4bd1c80 (LWP 10917))] (gdb) bt #0 0x00005577f6127dad in bdrv_io_plug (bs=0x5577f7ae52f0) at qemu/block/io.c:2650 #1 0x00005577f6114363 in blk_io_plug (blk=0x5577f7b8ba20) at qemu/block/block-backend.c:1561 #2 0x00005577f5d4091d in virtio_blk_handle_vq (s=0x5577f9ada030, vq=0x5577f9b3d2a0) at qemu/hw/block/virtio-blk.c:589 #3 0x00005577f5d4240d in virtio_blk_data_plane_handle_output (vdev=0x5577f9ada030, vq=0x5577f9b3d2a0) at qemu/hw/block/dataplane/virtio-blk.c:158 #4 0x00005577f5d88acd in virtio_queue_notify_aio_vq (vq=0x5577f9b3d2a0) at qemu/hw/virtio/virtio.c:1304 #5 0x00005577f5d8aaaf in virtio_queue_host_notifier_aio_poll (opaque=0x5577f9b3d308) at qemu/hw/virtio/virtio.c:2134 #6 0x00005577f60ca077 in run_poll_handlers_once (ctx=0x5577f79ddbb0) at qemu/aio-posix.c:493 #7 0x00005577f60ca268 in try_poll_mode (ctx=0x5577f79ddbb0, blocking=true) at qemu/aio-posix.c:569 #8 0x00005577f60ca331 in aio_poll (ctx=0x5577f79ddbb0, blocking=true) at qemu/aio-posix.c:601 #9 0x00005577f612722a in bdrv_flush (bs=0x5577f7c20970) at qemu/block/io.c:2403 #10 0x00005577f60c1b2d in bdrv_close (bs=0x5577f7c20970) at qemu/block.c:2322 #11 0x00005577f60c20e7 in bdrv_delete (bs=0x5577f7c20970) at qemu/block.c:2465 #12 0x00005577f60c3ecf in bdrv_unref (bs=0x5577f7c20970) at qemu/block.c:3425 #13 0x00005577f60bf951 in bdrv_root_unref_child (child=0x5577f7a2de70) at qemu/block.c:1361 #14 0x00005577f6112162 in blk_remove_bs (blk=0x5577f7b8ba20) at qemu/block/block-backend.c:491 #15 0x00005577f6111b1b in blk_remove_all_bs () at qemu/block/block-backend.c:245 #16 0x00005577f60c1db6 in bdrv_close_all () at qemu/block.c:2382 #17 0x00005577f5e60cca in main (argc=20, argv=0x7ffea6eb8398, envp=0x7ffea6eb8440) at qemu/vl.c:4684 The key thing is that bdrv_close() uses bdrv_drained_begin() and virtio_queue_host_notifier_aio_poll() must not be called. Thanks to Fam Zheng <famz@redhat.com> for identifying the root cause of this crash. Reported-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Tested-by: Alberto Garcia <berto@igalia.com> Message-id: 20170124095350.16679-1-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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moyix
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Feb 8, 2019
During block job completion, nothing is preventing
block_job_defer_to_main_loop_bh from being called in a nested
aio_poll(), which is a trouble, such as in this code path:
qmp_block_commit
commit_active_start
bdrv_reopen
bdrv_reopen_multiple
bdrv_reopen_prepare
bdrv_flush
aio_poll
aio_bh_poll
aio_bh_call
block_job_defer_to_main_loop_bh
stream_complete
bdrv_reopen
block_job_defer_to_main_loop_bh is the last step of the stream job,
which should have been "paused" by the bdrv_drained_begin/end in
bdrv_reopen_multiple, but it is not done because it's in the form of a
main loop BH.
Similar to why block jobs should be paused between drained_begin and
drained_end, BHs they schedule must be excluded as well. To achieve
this, this patch forces draining the BH in BDRV_POLL_WHILE.
As a side effect this fixes a hang in block_job_detach_aio_context
during system_reset when a block job is ready:
#0 0x0000555555aa79f3 in bdrv_drain_recurse
#1 0x0000555555aa825d in bdrv_drained_begin
#2 0x0000555555aa8449 in bdrv_drain
#3 0x0000555555a9c356 in blk_drain
#4 0x0000555555aa3cfd in mirror_drain
#5 0x0000555555a66e11 in block_job_detach_aio_context
#6 0x0000555555a62f4d in bdrv_detach_aio_context
#7 0x0000555555a63116 in bdrv_set_aio_context
#8 0x0000555555a9d326 in blk_set_aio_context
#9 0x00005555557e38da in virtio_blk_data_plane_stop
#10 0x00005555559f9d5f in virtio_bus_stop_ioeventfd
#11 0x00005555559fa49b in virtio_bus_stop_ioeventfd
#12 0x00005555559f6a18 in virtio_pci_stop_ioeventfd
#13 0x00005555559f6a18 in virtio_pci_reset
#14 0x00005555559139a9 in qdev_reset_one
#15 0x0000555555916738 in qbus_walk_children
#16 0x0000555555913318 in qdev_walk_children
#17 0x0000555555916738 in qbus_walk_children
#18 0x00005555559168ca in qemu_devices_reset
#19 0x000055555581fcbb in pc_machine_reset
#20 0x00005555558a4d96 in qemu_system_reset
#21 0x000055555577157a in main_loop_should_exit
#22 0x000055555577157a in main_loop
#23 0x000055555577157a in main
The rationale is that the loop in block_job_detach_aio_context cannot
make any progress in pausing/completing the job, because bs->in_flight
is 0, so bdrv_drain doesn't process the block_job_defer_to_main_loop
BH. With this patch, it does.
Reported-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170418143044.12187-3-famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Tested-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
AndrewFasano
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Oct 16, 2023
Both virtio-blk and virtio-scsi use virtio_queue_empty() as the
loop condition in VQ handlers (virtio_blk_handle_vq,
virtio_scsi_handle_cmd_vq). When a device is marked broken in
virtqueue_pop, for example if a vIOMMU address translation failed, we
want to break out of the loop.
This fixes a hanging problem when booting a CentOS 3.10.0-862.el7.x86_64
kernel with ATS enabled:
$ qemu-system-x86_64 \
... \
-device intel-iommu,intremap=on,caching-mode=on,eim=on,device-iotlb=on \
-device virtio-scsi-pci,iommu_platform=on,ats=on,id=scsi0,bus=pci.4,addr=0x0
The dead loop happens immediately when the kernel boots and initializes
the device, where virtio_scsi_data_plane_handle_cmd will not return:
> ...
> #13 0x00005586602b7793 in virtio_scsi_handle_cmd_vq
> #14 0x00005586602b8d66 in virtio_scsi_data_plane_handle_cmd
> #15 0x00005586602ddab7 in virtio_queue_notify_aio_vq
> #16 0x00005586602dfc9f in virtio_queue_host_notifier_aio_poll
> #17 0x00005586607885da in run_poll_handlers_once
> #18 0x000055866078880e in try_poll_mode
> #19 0x00005586607888eb in aio_poll
> #20 0x0000558660784561 in aio_wait_bh_oneshot
> #21 0x00005586602b9582 in virtio_scsi_dataplane_stop
> #22 0x00005586605a7110 in virtio_bus_stop_ioeventfd
> #23 0x00005586605a9426 in virtio_pci_stop_ioeventfd
> #24 0x00005586605ab808 in virtio_pci_common_write
> #25 0x0000558660242396 in memory_region_write_accessor
> #26 0x00005586602425ab in access_with_adjusted_size
> #27 0x0000558660245281 in memory_region_dispatch_write
> #28 0x00005586601e008e in flatview_write_continue
> #29 0x00005586601e01d8 in flatview_write
> #30 0x00005586601e04de in address_space_write
> #31 0x00005586601e052f in address_space_rw
> #32 0x00005586602607f2 in kvm_cpu_exec
> #33 0x0000558660227148 in qemu_kvm_cpu_thread_fn
> #34 0x000055866078bde7 in qemu_thread_start
> #35 0x00007f5784906594 in start_thread
> #36 0x00007f5784639e6f in clone
With this patch, virtio_queue_empty will now return 1 as soon as the
vdev is marked as broken, after a "virtio: zero sized buffers are not
allowed" error.
To be consistent, update virtio_queue_empty_rcu as well.
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20180910145616.8598-2-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
AndrewFasano
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Oct 16, 2023
Currently the SLOF firmware for pseries guests will disable/re-enable a PCI device multiple times via IO/MEM/MASTER bits of PCI_COMMAND register after the initial probe/feature negotiation, as it tends to work with a single device at a time at various stages like probing and running block/network bootloaders without doing a full reset in-between. In QEMU, when PCI_COMMAND_MASTER is disabled we disable the corresponding IOMMU memory region, so DMA accesses (including to vring fields like idx/flags) will no longer undergo the necessary translation. Normally we wouldn't expect this to happen since it would be misbehavior on the driver side to continue driving DMA requests. However, in the case of pseries, with iommu_platform=on, we trigger the following sequence when tearing down the virtio-blk dataplane ioeventfd in response to the guest unsetting PCI_COMMAND_MASTER: #2 0x0000555555922651 in virtqueue_map_desc (vdev=vdev@entry=0x555556dbcfb0, p_num_sg=p_num_sg@entry=0x7fffe657e1a8, addr=addr@entry=0x7fffe657e240, iov=iov@entry=0x7fffe6580240, max_num_sg=max_num_sg@entry=1024, is_write=is_write@entry=false, pa=0, sz=0) at /home/mdroth/w/qemu.git/hw/virtio/virtio.c:757 #3 0x0000555555922a89 in virtqueue_pop (vq=vq@entry=0x555556dc8660, sz=sz@entry=184) at /home/mdroth/w/qemu.git/hw/virtio/virtio.c:950 #4 0x00005555558d3eca in virtio_blk_get_request (vq=0x555556dc8660, s=0x555556dbcfb0) at /home/mdroth/w/qemu.git/hw/block/virtio-blk.c:255 #5 0x00005555558d3eca in virtio_blk_handle_vq (s=0x555556dbcfb0, vq=0x555556dc8660) at /home/mdroth/w/qemu.git/hw/block/virtio-blk.c:776 #6 0x000055555591dd66 in virtio_queue_notify_aio_vq (vq=vq@entry=0x555556dc8660) at /home/mdroth/w/qemu.git/hw/virtio/virtio.c:1550 #7 0x000055555591ecef in virtio_queue_notify_aio_vq (vq=0x555556dc8660) at /home/mdroth/w/qemu.git/hw/virtio/virtio.c:1546 #8 0x000055555591ecef in virtio_queue_host_notifier_aio_poll (opaque=0x555556dc86c8) at /home/mdroth/w/qemu.git/hw/virtio/virtio.c:2527 #9 0x0000555555d02164 in run_poll_handlers_once (ctx=ctx@entry=0x55555688bfc0, timeout=timeout@entry=0x7fffe65844a8) at /home/mdroth/w/qemu.git/util/aio-posix.c:520 #10 0x0000555555d02d1b in try_poll_mode (timeout=0x7fffe65844a8, ctx=0x55555688bfc0) at /home/mdroth/w/qemu.git/util/aio-posix.c:607 #11 0x0000555555d02d1b in aio_poll (ctx=ctx@entry=0x55555688bfc0, blocking=blocking@entry=true) at /home/mdroth/w/qemu.git/util/aio-posix.c:639 #12 0x0000555555d0004d in aio_wait_bh_oneshot (ctx=0x55555688bfc0, cb=cb@entry=0x5555558d5130 <virtio_blk_data_plane_stop_bh>, opaque=opaque@entry=0x555556de86f0) at /home/mdroth/w/qemu.git/util/aio-wait.c:71 #13 0x00005555558d59bf in virtio_blk_data_plane_stop (vdev=<optimized out>) at /home/mdroth/w/qemu.git/hw/block/dataplane/virtio-blk.c:288 #14 0x0000555555b906a1 in virtio_bus_stop_ioeventfd (bus=bus@entry=0x555556dbcf38) at /home/mdroth/w/qemu.git/hw/virtio/virtio-bus.c:245 #15 0x0000555555b90dbb in virtio_bus_stop_ioeventfd (bus=bus@entry=0x555556dbcf38) at /home/mdroth/w/qemu.git/hw/virtio/virtio-bus.c:237 #16 0x0000555555b92a8e in virtio_pci_stop_ioeventfd (proxy=0x555556db4e40) at /home/mdroth/w/qemu.git/hw/virtio/virtio-pci.c:292 #17 0x0000555555b92a8e in virtio_write_config (pci_dev=0x555556db4e40, address=<optimized out>, val=1048832, len=<optimized out>) at /home/mdroth/w/qemu.git/hw/virtio/virtio-pci.c:613 I.e. the calling code is only scheduling a one-shot BH for virtio_blk_data_plane_stop_bh, but somehow we end up trying to process an additional virtqueue entry before we get there. This is likely due to the following check in virtio_queue_host_notifier_aio_poll: static bool virtio_queue_host_notifier_aio_poll(void *opaque) { EventNotifier *n = opaque; VirtQueue *vq = container_of(n, VirtQueue, host_notifier); bool progress; if (!vq->vring.desc || virtio_queue_empty(vq)) { return false; } progress = virtio_queue_notify_aio_vq(vq); namely the call to virtio_queue_empty(). In this case, since no new requests have actually been issued, shadow_avail_idx == last_avail_idx, so we actually try to access the vring via vring_avail_idx() to get the latest non-shadowed idx: int virtio_queue_empty(VirtQueue *vq) { bool empty; ... if (vq->shadow_avail_idx != vq->last_avail_idx) { return 0; } rcu_read_lock(); empty = vring_avail_idx(vq) == vq->last_avail_idx; rcu_read_unlock(); return empty; but since the IOMMU region has been disabled we get a bogus value (0 usually), which causes virtio_queue_empty() to falsely report that there are entries to be processed, which causes errors such as: "virtio: zero sized buffers are not allowed" or "virtio-blk missing headers" and puts the device in an error state. This patch works around the issue by introducing virtio_set_disabled(), which sets a 'disabled' flag to bypass checks like virtio_queue_empty() when bus-mastering is disabled. Since we'd check this flag at all the same sites as vdev->broken, we replace those checks with an inline function which checks for either vdev->broken or vdev->disabled. The 'disabled' flag is only migrated when set, which should be fairly rare, but to maintain migration compatibility we disable it's use for older machine types. Users requiring the use of the flag in conjunction with older machine types can set it explicitly as a virtio-device option. NOTES: - This leaves some other oddities in play, like the fact that DRIVER_OK also gets unset in response to bus-mastering being disabled, but not restored (however the device seems to continue working) - Similarly, we disable the host notifier via virtio_bus_stop_ioeventfd(), which seems to move the handling out of virtio-blk dataplane and back into the main IO thread, and it ends up staying there till a reset (but otherwise continues working normally) Cc: David Gibson <david@gibson.dropbear.id.au>, Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: "Michael S. Tsirkin" <mst@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> Message-Id: <20191120005003.27035-1-mdroth@linux.vnet.ibm.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
AndrewFasano
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Oct 16, 2023
The virtqueue code sets up MemoryRegionCaches to access the virtqueue
guest RAM data structures. The code currently assumes that
VRingMemoryRegionCaches is initialized before device emulation code
accesses the virtqueue. An assertion will fail in
vring_get_region_caches() when this is not true. Device fuzzing found a
case where this assumption is false (see below).
Virtqueue guest RAM addresses can also be changed from a vCPU thread
while an IOThread is accessing the virtqueue. This breaks the same
assumption but this time the caches could become invalid partway through
the virtqueue code. The code fetches the caches RCU pointer multiple
times so we will need to validate the pointer every time it is fetched.
Add checks each time we call vring_get_region_caches() and treat invalid
caches as a nop: memory stores are ignored and memory reads return 0.
The fuzz test failure is as follows:
$ qemu -M pc -device virtio-blk-pci,id=drv0,drive=drive0,addr=4.0 \
-drive if=none,id=drive0,file=null-co://,format=raw,auto-read-only=off \
-drive if=none,id=drive1,file=null-co://,file.read-zeroes=on,format=raw \
-display none \
-qtest stdio
endianness
outl 0xcf8 0x80002020
outl 0xcfc 0xe0000000
outl 0xcf8 0x80002004
outw 0xcfc 0x7
write 0xe0000000 0x24 0x00ffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffab5cffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffabffffffab0000000001
inb 0x4
writew 0xe000001c 0x1
write 0xe0000014 0x1 0x0d
The following error message is produced:
qemu-system-x86_64: /home/stefanha/qemu/hw/virtio/virtio.c:286: vring_get_region_caches: Assertion `caches != NULL' failed.
The backtrace looks like this:
#0 0x00007ffff5520625 in raise () at /lib64/libc.so.6
#1 0x00007ffff55098d9 in abort () at /lib64/libc.so.6
#2 0x00007ffff55097a9 in _nl_load_domain.cold () at /lib64/libc.so.6
#3 0x00007ffff5518a66 in annobin_assert.c_end () at /lib64/libc.so.6
#4 0x00005555559073da in vring_get_region_caches (vq=<optimized out>) at qemu/hw/virtio/virtio.c:286
#5 vring_get_region_caches (vq=<optimized out>) at qemu/hw/virtio/virtio.c:283
#6 0x000055555590818d in vring_used_flags_set_bit (mask=1, vq=0x5555575ceea0) at qemu/hw/virtio/virtio.c:398
#7 virtio_queue_split_set_notification (enable=0, vq=0x5555575ceea0) at qemu/hw/virtio/virtio.c:398
#8 virtio_queue_set_notification (vq=vq@entry=0x5555575ceea0, enable=enable@entry=0) at qemu/hw/virtio/virtio.c:451
#9 0x0000555555908512 in virtio_queue_set_notification (vq=vq@entry=0x5555575ceea0, enable=enable@entry=0) at qemu/hw/virtio/virtio.c:444
#10 0x00005555558c697a in virtio_blk_handle_vq (s=0x5555575c57e0, vq=0x5555575ceea0) at qemu/hw/block/virtio-blk.c:775
#11 0x0000555555907836 in virtio_queue_notify_aio_vq (vq=0x5555575ceea0) at qemu/hw/virtio/virtio.c:2244
#12 0x0000555555cb5dd7 in aio_dispatch_handlers (ctx=ctx@entry=0x55555671a420) at util/aio-posix.c:429
#13 0x0000555555cb67a8 in aio_dispatch (ctx=0x55555671a420) at util/aio-posix.c:460
#14 0x0000555555cb307e in aio_ctx_dispatch (source=<optimized out>, callback=<optimized out>, user_data=<optimized out>) at util/async.c:260
#15 0x00007ffff7bbc510 in g_main_context_dispatch () at /lib64/libglib-2.0.so.0
#16 0x0000555555cb5848 in glib_pollfds_poll () at util/main-loop.c:219
#17 os_host_main_loop_wait (timeout=<optimized out>) at util/main-loop.c:242
#18 main_loop_wait (nonblocking=<optimized out>) at util/main-loop.c:518
#19 0x00005555559b20c9 in main_loop () at vl.c:1683
#20 0x0000555555838115 in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4441
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Cc: Michael Tsirkin <mst@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200207104619.164892-1-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
AndrewFasano
pushed a commit
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this issue
Oct 16, 2023
when s->inflight is freed, vhost_dev_free_inflight may try to access
s->inflight->addr, it will retrigger the following issue.
==7309==ERROR: AddressSanitizer: heap-use-after-free on address 0x604001020d18 at pc 0x555555ce948a bp 0x7fffffffb170 sp 0x7fffffffb160
READ of size 8 at 0x604001020d18 thread T0
#0 0x555555ce9489 in vhost_dev_free_inflight /root/smartx/qemu-el7/qemu-test/hw/virtio/vhost.c:1473
#1 0x555555cd86eb in virtio_reset /root/smartx/qemu-el7/qemu-test/hw/virtio/virtio.c:1214
#2 0x5555560d3eff in virtio_pci_reset hw/virtio/virtio-pci.c:1859
#3 0x555555f2ac53 in device_set_realized hw/core/qdev.c:893
#4 0x5555561d572c in property_set_bool qom/object.c:1925
#5 0x5555561de8de in object_property_set_qobject qom/qom-qobject.c:27
#6 0x5555561d99f4 in object_property_set_bool qom/object.c:1188
#7 0x555555e50ae7 in qdev_device_add /root/smartx/qemu-el7/qemu-test/qdev-monitor.c:626
#8 0x555555e51213 in qmp_device_add /root/smartx/qemu-el7/qemu-test/qdev-monitor.c:806
#9 0x555555e8ff40 in hmp_device_add /root/smartx/qemu-el7/qemu-test/hmp.c:1951
#10 0x555555be889a in handle_hmp_command /root/smartx/qemu-el7/qemu-test/monitor.c:3404
#11 0x555555beac8b in monitor_command_cb /root/smartx/qemu-el7/qemu-test/monitor.c:4296
#12 0x555556433eb7 in readline_handle_byte util/readline.c:393
#13 0x555555be89ec in monitor_read /root/smartx/qemu-el7/qemu-test/monitor.c:4279
#14 0x5555563285cc in tcp_chr_read chardev/char-socket.c:470
#15 0x7ffff670b968 in g_main_context_dispatch (/lib64/libglib-2.0.so.0+0x4a968)
#16 0x55555640727c in glib_pollfds_poll util/main-loop.c:215
#17 0x55555640727c in os_host_main_loop_wait util/main-loop.c:238
#18 0x55555640727c in main_loop_wait util/main-loop.c:497
#19 0x555555b2d0bf in main_loop /root/smartx/qemu-el7/qemu-test/vl.c:2013
#20 0x555555b2d0bf in main /root/smartx/qemu-el7/qemu-test/vl.c:4776
#21 0x7fffdd2eb444 in __libc_start_main (/lib64/libc.so.6+0x22444)
#22 0x555555b3767a (/root/smartx/qemu-el7/qemu-test/x86_64-softmmu/qemu-system-x86_64+0x5e367a)
0x604001020d18 is located 8 bytes inside of 40-byte region [0x604001020d10,0x604001020d38)
freed by thread T0 here:
#0 0x7ffff6f00508 in __interceptor_free (/lib64/libasan.so.4+0xde508)
#1 0x7ffff671107d in g_free (/lib64/libglib-2.0.so.0+0x5007d)
previously allocated by thread T0 here:
#0 0x7ffff6f00a88 in __interceptor_calloc (/lib64/libasan.so.4+0xdea88)
#1 0x7ffff6710fc5 in g_malloc0 (/lib64/libglib-2.0.so.0+0x4ffc5)
SUMMARY: AddressSanitizer: heap-use-after-free /root/smartx/qemu-el7/qemu-test/hw/virtio/vhost.c:1473 in vhost_dev_free_inflight
Shadow bytes around the buggy address:
0x0c08801fc150: fa fa 00 00 00 00 04 fa fa fa fd fd fd fd fd fa
0x0c08801fc160: fa fa fd fd fd fd fd fd fa fa 00 00 00 00 04 fa
0x0c08801fc170: fa fa 00 00 00 00 00 01 fa fa 00 00 00 00 04 fa
0x0c08801fc180: fa fa 00 00 00 00 00 01 fa fa 00 00 00 00 00 01
0x0c08801fc190: fa fa 00 00 00 00 00 fa fa fa 00 00 00 00 04 fa
=>0x0c08801fc1a0: fa fa fd[fd]fd fd fd fa fa fa fd fd fd fd fd fa
0x0c08801fc1b0: fa fa fd fd fd fd fd fa fa fa fd fd fd fd fd fa
0x0c08801fc1c0: fa fa 00 00 00 00 00 fa fa fa fd fd fd fd fd fd
0x0c08801fc1d0: fa fa 00 00 00 00 00 01 fa fa fd fd fd fd fd fa
0x0c08801fc1e0: fa fa fd fd fd fd fd fa fa fa fd fd fd fd fd fd
0x0c08801fc1f0: fa fa 00 00 00 00 00 01 fa fa fd fd fd fd fd fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==7309==ABORTING
Signed-off-by: Li Feng <fengli@smartx.com>
Message-Id: <20200417101707.14467-1-fengli@smartx.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
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The current version of the snapshot format does not include a length field for its sections. This is logical for loadvm where any missing device is fatal but not for replay where only core devices and devices tracked by plug-ins are needed. It would also be nice to be able to include plug in state information in a snapshot, eg the FD tracker's state or DroidScope's state, without requiring them to be active on loading the snapshot.
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