Documentation for plugins #6

moyix · 2014-06-21T22:23:51Z

We need some documentation for existing plugins. Some have a bit already, such as the taint plugin, but most are completely undocumented.

yizhibenpao · 2014-11-23T08:19:17Z

Please provide detailed documentation for each plugin, functions, usage scenarios, input/output parameter, and so on.

m000 · 2014-12-15T17:19:50Z

Maybe start with adding a README.md in the panda_plugins directory? This won't contain extensive documentation, but at least users will have a vague idea about what to expect from each plugin.

yizhibenpao · 2014-12-16T12:23:24Z

Many plugins are not documents, API no documents, so it's hard to write a plug-in. Hope that corresponds to add plug-in can also write documentation.。

moyix · 2014-12-18T03:03:03Z

The plugin API is documented, actually – look at docs/PANDA.md. But individual plugins are indeed undocumented. Trying to find time to add at least a brief summary about each soon :|

volpino · 2015-02-26T14:09:56Z

What is the difference between taint and taint2? And between syscall and syscall2?

I can understand that it requires time to document everything and sometimes just the name, reading the code or the comments in there give enough information. But in those cases at least a more meaningful name or one line that states why there is another version of the same plugin would be appreciated.

m000 · 2015-02-27T18:51:32Z

Would it make sense to move some of the older plugins in a panda_plugins/deprecated directory?
Anyone who wishes to try them out he can find them there. The rest will see the up-to-date versions by default.

moyix · 2015-02-27T19:15:19Z

That's probably a good idea. For syscalls at least, it has been fully replaced by syscalls2. With taint2 vs taint, I believe taint2 is still missing some features like HDD / network taint.

phulin · 2015-02-27T19:54:34Z

Yes - taint2 is still under pretty rapid development. We still need to add
hdd/network taint, and we still need to fix some algorithm/data structure
issues (i.e. performance) issues.

On Fri, Feb 27, 2015 at 2:15 PM, Brendan Dolan-Gavitt <
notifications@github.com> wrote:

That's probably a good idea. For syscalls at least, it has been fully
replaced by syscalls2. With taint2 vs taint, I believe taint2 is still
missing some features like HDD / network taint.

—
Reply to this email directly or view it on GitHub
https://github.com/moyix/panda/issues/6#issuecomment-76453733.

Current code that handles Tx buffer desciprtor ring scanning employs the following algorithm: 1. Restore current buffer descriptor pointer from TBPTRn 2. Process current descriptor 3. If current descriptor has BD_WRAP flag set set current descriptor pointer to start of the descriptor ring 4. If current descriptor points to start of the ring exit the loop, otherwise increment current descriptor pointer and go to #2 5. Store current descriptor in TBPTRn The way the code is implemented results in buffer descriptor ring being scanned starting at offset/descriptor #0. While covering 99% of the cases, this algorithm becomes problematic for a number of edge cases. Consider the following scenario: guest OS driver initializes descriptor ring to N individual descriptors and starts sending data out. Depending on the volume of traffic and probably guest OS driver implementation it is possible that an edge case where a packet, spread across 2 descriptors is placed in descriptors N - 1 and 0 in that order(it is easy to imagine similar examples involving more than 2 descriptors). What happens then is aforementioned algorithm starts at descriptor 0, sees a descriptor marked as BD_LAST, which it happily sends out as a separate packet(very much malformed at this point) then the iteration continues and the first part of the original packet is tacked to the next transmission which ends up being bogus as well. This behvaiour can be pretty reliably observed when scp'ing data from a guest OS via TAP interface for files larger than 160K (every time for 700K+). This patch changes the scanning algorithm to do the following: 1. Restore "current" buffer descriptor pointer from TBPTRn 2. If "current" descriptor does not have BD_TX_READY set, goto #6 3. Process current descriptor 4. If "current" descriptor has BD_WRAP flag set "current" descriptor pointer to start of the descriptor ring otherwise set increment "current" by the size of one descriptor 5. Goto #1 6. Save "current" buffer descriptor in TBPTRn This way we preserve the information about which descriptor was processed last and always start where we left off avoiding the original problem. On top of that, judging by the following excerpt from MPC8548ERM (p. 14-48): "... When the end of the TxBD ring is reached, eTSEC initializes TBPTRn to the value in the corresponding TBASEn. The TBPTR register is internally written by the eTSEC’s DMA controller during transmission. The pointer increments by eight (bytes) each time a descriptor is closed successfully by the eTSEC..." revised algorithm might also a more correct way of emulating this aspect of eTSEC peripheral. Cc: Alexander Graf <agraf@suse.de> Cc: Scott Wood <scottwood@freescale.com> Cc: Jason Wang <jasowang@redhat.com> Cc: qemu-devel@nongnu.org Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> Signed-off-by: Jason Wang <jasowang@redhat.com>

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>

This reverts commit aff8fd1. Both virtio-net and virtio-crypto do not balance virtio_queue_set_notification() enable and disable calls. This makes the notifications_disabled counter unreliable and Doug Goldstein reported the following assertion failure: #3 0x00007ffff44d1c62 in __GI___assert_fail ( assertion=assertion@entry=0x555555ae8e8a "vq->notification_disabled > 0", file=file@entry=0x555555ae89c0 "/home/doug/work/qemu/hw/virtio/virtio.c", line=line@entry=215, function=function@entry=0x555555ae9630 <__PRETTY_FUNCTION__.43707> "virtio_queue_set_notification") at assert.c:101 #4 0x00005555557f25d6 in virtio_queue_set_notification (vq=0x55555666aa90, enable=enable@entry=1) at /home/doug/work/qemu/hw/virtio/virtio.c:215 #5 0x00005555557dc311 in virtio_net_has_buffers (q=<optimized out>, q=<optimized out>, bufsize=102) at /home/doug/work/qemu/hw/net/virtio-net.c:1008 #6 virtio_net_receive (nc=<optimized out>, buf=0x555557386b88 "", size=102) at /home/doug/work/qemu/hw/net/virtio-net.c:1148 #7 0x00005555559cad33 in nc_sendv_compat (flags=<optimized out>, iovcnt=1, iov=0x7fffead746d0, nc=0x55555788b340) at net/net.c:705 #8 qemu_deliver_packet_iov (sender=<optimized out>, flags=<optimized out>, iov=0x7fffead746d0, iovcnt=1, opaque=0x55555788b340) at net/net.c:732 #9 0x00005555559cd929 in qemu_net_queue_deliver (size=<optimized out>, data=<optimized out>, flags=<optimized out>, sender=<optimized out>, queue=0x55555788b550) at net/queue.c:164 #10 qemu_net_queue_flush (queue=0x55555788b550) at net/queue.c:261 This patch is safe to revert since it's just an optimization for virtqueue polling. The next patch will improve the situation again without resorting to nesting. Reported-by: Doug Goldstein <cardoe@cardoe.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Richard Henderson <rth@twiddle.net> Tested-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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>

This commit fixes a bug which causes the guest to hang. The bug was observed upon a "receive overrun" (bit panda-re#6 of the ICR register) interrupt which could be triggered post migration in a heavy traffic environment. Even though the "receive overrun" bit (panda-re#6) is masked out by the IMS register (refer to the log below) the driver still receives an interrupt as the "receive overrun" bit (panda-re#6) causes the "Other" - bit panda-re#24 of the ICR register - bit to be set as documented below. The driver handles the interrupt and clears the "Other" bit (panda-re#24) but doesn't clear the "receive overrun" bit (panda-re#6) which leads to an infinite loop. Apparently the Windows driver expects that the "receive overrun" bit and other ones - documented below - to be cleared when the "Other" bit (panda-re#24) is cleared. So to sum that up: 1. Bit panda-re#6 of the ICR register is set by heavy traffic 2. As a results of setting bit panda-re#6, bit panda-re#24 is set 3. The driver receives an interrupt for bit 24 (it doesn't receieve an interrupt for bit panda-re#6 as it is masked out by IMS) 4. The driver handles and clears the interrupt of bit panda-re#24 5. Bit panda-re#6 is still set. 6. 2 happens all over again The Interrupt Cause Read - ICR register: The ICR has the "Other" bit - bit panda-re#24 - that is set when one or more of the following ICR register's bits are set: LSC - bit panda-re#2, RXO - bit panda-re#6, MDAC - bit panda-re#9, SRPD - bit panda-re#16, ACK - bit panda-re#17, MNG - bit panda-re#18 This bug can occur with any of these bits depending on the driver's behaviour and the way it configures the device. However, trying to reproduce it with any bit other than RX0 is challenging and came to failure as the drivers don't implement most of these bits, trying to reproduce it with LSC (Link Status Change - bit panda-re#2) bit didn't succeed too as it seems that Windows handles this bit differently. Log sample of the storm: 27563@1494850819.411877:e1000e_irq_pending_interrupts ICR PENDING: 0x1000000 (ICR: 0x815000c2, IMS: 0x1a00004) 27563@1494850819.411900:e1000e_irq_pending_interrupts ICR PENDING: 0x0 (ICR: 0x815000c2, IMS: 0xa00004) 27563@1494850819.411915:e1000e_irq_pending_interrupts ICR PENDING: 0x0 (ICR: 0x815000c2, IMS: 0xa00004) 27563@1494850819.412380:e1000e_irq_pending_interrupts ICR PENDING: 0x0 (ICR: 0x815000c2, IMS: 0xa00004) 27563@1494850819.412395:e1000e_irq_pending_interrupts ICR PENDING: 0x0 (ICR: 0x815000c2, IMS: 0xa00004) 27563@1494850819.412436:e1000e_irq_pending_interrupts ICR PENDING: 0x0 (ICR: 0x815000c2, IMS: 0xa00004) 27563@1494850819.412441:e1000e_irq_pending_interrupts ICR PENDING: 0x0 (ICR: 0x815000c2, IMS: 0xa00004) 27563@1494850819.412998:e1000e_irq_pending_interrupts ICR PENDING: 0x1000000 (ICR: 0x815000c2, IMS: 0x1a00004) * This bug behaviour wasn't observed with the Linux driver. This commit solves: https://bugzilla.redhat.com/show_bug.cgi?id=1447935 https://bugzilla.redhat.com/show_bug.cgi?id=1449490 Cc: qemu-stable@nongnu.org Signed-off-by: Sameeh Jubran <sjubran@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> (cherry picked from commit 82342e9) Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

Running postcopy-test with ASAN produces the following error: QTEST_QEMU_BINARY=ppc64-softmmu/qemu-system-ppc64 tests/postcopy-test ... ================================================================= ==23641==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f1556600000 at pc 0x55b8e9d28208 bp 0x7f1555f4d3c0 sp 0x7f1555f4d3b0 READ of size 8 at 0x7f1556600000 thread T6 #0 0x55b8e9d28207 in htab_save_first_pass /home/elmarco/src/qq/hw/ppc/spapr.c:1528 #1 0x55b8e9d2939c in htab_save_iterate /home/elmarco/src/qq/hw/ppc/spapr.c:1665 #2 0x55b8e9beae3a in qemu_savevm_state_iterate /home/elmarco/src/qq/migration/savevm.c:1044 #3 0x55b8ea677733 in migration_thread /home/elmarco/src/qq/migration/migration.c:1976 #4 0x7f15845f46c9 in start_thread (/lib64/libpthread.so.0+0x76c9) #5 0x7f157d9d0f7e in clone (/lib64/libc.so.6+0x107f7e) 0x7f1556600000 is located 0 bytes to the right of 2097152-byte region [0x7f1556400000,0x7f1556600000) allocated by thread T0 here: #0 0x7f159bb76980 in posix_memalign (/lib64/libasan.so.3+0xc7980) #1 0x55b8eab185b2 in qemu_try_memalign /home/elmarco/src/qq/util/oslib-posix.c:106 #2 0x55b8eab186c8 in qemu_memalign /home/elmarco/src/qq/util/oslib-posix.c:122 #3 0x55b8e9d268a8 in spapr_reallocate_hpt /home/elmarco/src/qq/hw/ppc/spapr.c:1214 #4 0x55b8e9d26e04 in ppc_spapr_reset /home/elmarco/src/qq/hw/ppc/spapr.c:1261 #5 0x55b8ea12e913 in qemu_system_reset /home/elmarco/src/qq/vl.c:1697 #6 0x55b8ea13fa40 in main /home/elmarco/src/qq/vl.c:4679 #7 0x7f157d8e9400 in __libc_start_main (/lib64/libc.so.6+0x20400) Thread T6 created by T0 here: #0 0x7f159bae0488 in __interceptor_pthread_create (/lib64/libasan.so.3+0x31488) #1 0x55b8eab1d9cb in qemu_thread_create /home/elmarco/src/qq/util/qemu-thread-posix.c:465 #2 0x55b8ea67874c in migrate_fd_connect /home/elmarco/src/qq/migration/migration.c:2096 #3 0x55b8ea66cbb0 in migration_channel_connect /home/elmarco/src/qq/migration/migration.c:500 #4 0x55b8ea678f38 in socket_outgoing_migration /home/elmarco/src/qq/migration/socket.c:87 #5 0x55b8eaa5a03a in qio_task_complete /home/elmarco/src/qq/io/task.c:142 #6 0x55b8eaa599cc in gio_task_thread_result /home/elmarco/src/qq/io/task.c:88 #7 0x7f15823e38e6 (/lib64/libglib-2.0.so.0+0x468e6) SUMMARY: AddressSanitizer: heap-buffer-overflow /home/elmarco/src/qq/hw/ppc/spapr.c:1528 in htab_save_first_pass index seems to be wrongly incremented, unless I miss something that would be worth a comment. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

If, once the kernel has booted, we try to remove a memory hotplugged while the kernel was not started, QEMU crashes on an assert: qemu-system-ppc64: hw/virtio/vhost.c:651: vhost_commit: Assertion `r >= 0' failed. ... #4 in vhost_commit #5 in memory_region_transaction_commit #6 in pc_dimm_memory_unplug #7 in spapr_memory_unplug #8 spapr_machine_device_unplug #9 in hotplug_handler_unplug #10 in spapr_lmb_release #11 in detach #12 in set_allocation_state #13 in rtas_set_indicator ... If we take a closer look to the guest kernel log, we can see when we try to unplug the memory: pseries-hotplug-mem: Attempting to hot-add 4 LMB(s) What happens: 1- The kernel has ignored the memory hotplug event because it was not started when it was generated. 2- When we hot-unplug the memory, QEMU starts to remove the memory, generates an hot-unplug event, and signals the kernel of the incoming new event 3- as the kernel is started, on the QEMU signal, it reads the event list, decodes the hotplug event and tries to finish the hotplugging. 4- QEMU receive the the hotplug notification while it is trying to hot-unplug the memory. This moves the memory DRC to an invalid state This patch prevents this by not allowing to set the allocation state to USABLE while the DRC is awaiting release. RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1432382 Signed-off-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

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>

The following segfault is encountered if the NBD server closes the UNIX domain socket immediately after negotiation: Program terminated with signal SIGSEGV, Segmentation fault. #0 aio_co_schedule (ctx=0x0, co=0xd3c0ff2ef0) at util/async.c:441 441 QSLIST_INSERT_HEAD_ATOMIC(&ctx->scheduled_coroutines, (gdb) bt #0 0x000000d3c01a50f8 in aio_co_schedule (ctx=0x0, co=0xd3c0ff2ef0) at util/async.c:441 #1 0x000000d3c012fa90 in nbd_coroutine_end (bs=bs@entry=0xd3c0fec650, request=<optimized out>) at block/nbd-client.c:207 #2 0x000000d3c012fb58 in nbd_client_co_preadv (bs=0xd3c0fec650, offset=0, bytes=<optimized out>, qiov=0x7ffc10a91b20, flags=0) at block/nbd-client.c:237 #3 0x000000d3c0128e63 in bdrv_driver_preadv (bs=bs@entry=0xd3c0fec650, offset=offset@entry=0, bytes=bytes@entry=512, qiov=qiov@entry=0x7ffc10a91b20, flags=0) at block/io.c:836 #4 0x000000d3c012c3e0 in bdrv_aligned_preadv (child=child@entry=0xd3c0ff51d0, req=req@entry=0x7f31885d6e90, offset=offset@entry=0, bytes=bytes@entry=512, align=align@entry=1, qiov=qiov@entry=0x7ffc10a91b20, f +lags=0) at block/io.c:1086 #5 0x000000d3c012c6b8 in bdrv_co_preadv (child=0xd3c0ff51d0, offset=offset@entry=0, bytes=bytes@entry=512, qiov=qiov@entry=0x7ffc10a91b20, flags=flags@entry=0) at block/io.c:1182 #6 0x000000d3c011cc17 in blk_co_preadv (blk=0xd3c0ff4f80, offset=0, bytes=512, qiov=0x7ffc10a91b20, flags=0) at block/block-backend.c:1032 #7 0x000000d3c011ccec in blk_read_entry (opaque=0x7ffc10a91b40) at block/block-backend.c:1079 #8 0x000000d3c01bbb96 in coroutine_trampoline (i0=<optimized out>, i1=<optimized out>) at util/coroutine-ucontext.c:79 #9 0x00007f3196cb8600 in __start_context () at /lib64/libc.so.6 The problem is that nbd_client_init() uses nbd_client_attach_aio_context() -> aio_co_schedule(new_context, client->read_reply_co). Execution of read_reply_co is deferred to a BH which doesn't run until later. In the mean time blk_co_preadv() can be called and nbd_coroutine_end() calls aio_wake() on read_reply_co. At this point in time read_reply_co's ctx isn't set because it has never been entered yet. This patch simplifies the nbd_co_send_request() -> nbd_co_receive_reply() -> nbd_coroutine_end() lifecycle to just nbd_co_send_request() -> nbd_co_receive_reply(). The request is "ended" if an error occurs at any point. Callers no longer have to invoke nbd_coroutine_end(). This cleanup also eliminates the segfault because we don't call aio_co_schedule() to wake up s->read_reply_co if sending the request failed. It is only necessary to wake up s->read_reply_co if a reply was received. Note this only happens with UNIX domain sockets on Linux. It doesn't seem possible to reproduce this with TCP sockets. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20170829122745.14309-2-stefanha@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> (cherry picked from commit 3c2d518) Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

We can't know the caller read enough data in the memory pointed by ext_hdr to cast it as a ip6_ext_hdr_routing. Declare rt_hdr on the stack and fill it again from the iovec. Since we already checked there is enough data in the iovec buffer, simply add an assert() call to consume the bytes_read variable. This fix a 2 bytes buffer overrun in eth_parse_ipv6_hdr() reported by QEMU fuzzer: $ cat << EOF | ./qemu-system-i386 -M pc-q35-5.0 \ -accel qtest -monitor none \ -serial none -nographic -qtest stdio outl 0xcf8 0x80001010 outl 0xcfc 0xe1020000 outl 0xcf8 0x80001004 outw 0xcfc 0x7 write 0x25 0x1 0x86 write 0x26 0x1 0xdd write 0x4f 0x1 0x2b write 0xe1020030 0x4 0x190002e1 write 0xe102003a 0x2 0x0807 write 0xe1020048 0x4 0x12077cdd write 0xe1020400 0x4 0xba077cdd write 0xe1020420 0x4 0x190002e1 write 0xe1020428 0x4 0x3509d807 write 0xe1020438 0x1 0xe2 EOF ================================================================= ==2859770==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffdef904902 at pc 0x561ceefa78de bp 0x7ffdef904820 sp 0x7ffdef904818 READ of size 1 at 0x7ffdef904902 thread T0 #0 0x561ceefa78dd in _eth_get_rss_ex_dst_addr net/eth.c:410:17 #1 0x561ceefa41fb in eth_parse_ipv6_hdr net/eth.c:532:17 #2 0x561cef7de639 in net_tx_pkt_parse_headers hw/net/net_tx_pkt.c:228:14 #3 0x561cef7dbef4 in net_tx_pkt_parse hw/net/net_tx_pkt.c:273:9 #4 0x561ceec29f22 in e1000e_process_tx_desc hw/net/e1000e_core.c:730:29 #5 0x561ceec28eac in e1000e_start_xmit hw/net/e1000e_core.c:927:9 #6 0x561ceec1baab in e1000e_set_tdt hw/net/e1000e_core.c:2444:9 #7 0x561ceebf300e in e1000e_core_write hw/net/e1000e_core.c:3256:9 #8 0x561cef3cd4cd in e1000e_mmio_write hw/net/e1000e.c:110:5 Address 0x7ffdef904902 is located in stack of thread T0 at offset 34 in frame #0 0x561ceefa320f in eth_parse_ipv6_hdr net/eth.c:486 This frame has 1 object(s): [32, 34) 'ext_hdr' (line 487) <== Memory access at offset 34 overflows this variable HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork (longjmp and C++ exceptions *are* supported) SUMMARY: AddressSanitizer: stack-buffer-overflow net/eth.c:410:17 in _eth_get_rss_ex_dst_addr Shadow bytes around the buggy address: 0x10003df188d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df188e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df188f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df18900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df18910: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 =>0x10003df18920:[02]f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df18930: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df18940: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df18950: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df18960: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10003df18970: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Stack left redzone: f1 Stack right redzone: f3 ==2859770==ABORTING Add the corresponding qtest case with the fuzzer reproducer. FWIW GCC 11 similarly reported: net/eth.c: In function 'eth_parse_ipv6_hdr': net/eth.c:410:15: error: array subscript 'struct ip6_ext_hdr_routing[0]' is partly outside array bounds of 'struct ip6_ext_hdr[1]' [-Werror=array-bounds] 410 | if ((rthdr->rtype == 2) && (rthdr->segleft == 1)) { | ~~~~~^~~~~~~ net/eth.c:485:24: note: while referencing 'ext_hdr' 485 | struct ip6_ext_hdr ext_hdr; | ^~~~~~~ net/eth.c:410:38: error: array subscript 'struct ip6_ext_hdr_routing[0]' is partly outside array bounds of 'struct ip6_ext_hdr[1]' [-Werror=array-bounds] 410 | if ((rthdr->rtype == 2) && (rthdr->segleft == 1)) { | ~~~~~^~~~~~~~~ net/eth.c:485:24: note: while referencing 'ext_hdr' 485 | struct ip6_ext_hdr ext_hdr; | ^~~~~~~ Cc: qemu-stable@nongnu.org Buglink: https://bugs.launchpad.net/qemu/+bug/1879531 Reported-by: Alexander Bulekov <alxndr@bu.edu> Reported-by: Miroslav Rezanina <mrezanin@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Miroslav Rezanina <mrezanin@redhat.com> Fixes: eb70002 ("net_pkt: Extend packet abstraction as required by e1000e functionality") Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>

Receive/transmit/event vqs forgot to cleanup in vhost_vsock_unrealize. This patch save receive/transmit vq pointer in realize() and cleanup vqs through those vq pointers in unrealize(). The leak stack is as follow: Direct leak of 21504 byte(s) in 3 object(s) allocated from: #0 0x7f86a1356970 (/lib64/libasan.so.5+0xef970) ??:? #1 0x7f86a09aa49d (/lib64/libglib-2.0.so.0+0x5249d) ??:? #2 0x5604852f85ca (./x86_64-softmmu/qemu-system-x86_64+0x2c3e5ca) /mnt/sdb/qemu/hw/virtio/virtio.c:2333 #3 0x560485356208 (./x86_64-softmmu/qemu-system-x86_64+0x2c9c208) /mnt/sdb/qemu/hw/virtio/vhost-vsock.c:339 #4 0x560485305a17 (./x86_64-softmmu/qemu-system-x86_64+0x2c4ba17) /mnt/sdb/qemu/hw/virtio/virtio.c:3531 #5 0x5604858e6b65 (./x86_64-softmmu/qemu-system-x86_64+0x322cb65) /mnt/sdb/qemu/hw/core/qdev.c:865 #6 0x5604861e6c41 (./x86_64-softmmu/qemu-system-x86_64+0x3b2cc41) /mnt/sdb/qemu/qom/object.c:2102 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Message-Id: <20200115062535.50644-1-pannengyuan@huawei.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Currently offloads disabled by guest via the VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET command are not preserved on VM migration. Instead all offloads reported by guest features (via VIRTIO_PCI_GUEST_FEATURES) get enabled. What happens is: first the VirtIONet::curr_guest_offloads gets restored and offloads are getting set correctly: #0 qemu_set_offload (nc=0x555556a11400, csum=1, tso4=0, tso6=0, ecn=0, ufo=0) at net/net.c:474 #1 virtio_net_apply_guest_offloads (n=0x555557701ca0) at hw/net/virtio-net.c:720 #2 virtio_net_post_load_device (opaque=0x555557701ca0, version_id=11) at hw/net/virtio-net.c:2334 #3 vmstate_load_state (f=0x5555569dc010, vmsd=0x555556577c80 <vmstate_virtio_net_device>, opaque=0x555557701ca0, version_id=11) at migration/vmstate.c:168 #4 virtio_load (vdev=0x555557701ca0, f=0x5555569dc010, version_id=11) at hw/virtio/virtio.c:2197 #5 virtio_device_get (f=0x5555569dc010, opaque=0x555557701ca0, size=0, field=0x55555668cd00 <__compound_literal.5>) at hw/virtio/virtio.c:2036 #6 vmstate_load_state (f=0x5555569dc010, vmsd=0x555556577ce0 <vmstate_virtio_net>, opaque=0x555557701ca0, version_id=11) at migration/vmstate.c:143 #7 vmstate_load (f=0x5555569dc010, se=0x5555578189e0) at migration/savevm.c:829 #8 qemu_loadvm_section_start_full (f=0x5555569dc010, mis=0x5555569eee20) at migration/savevm.c:2211 #9 qemu_loadvm_state_main (f=0x5555569dc010, mis=0x5555569eee20) at migration/savevm.c:2395 #10 qemu_loadvm_state (f=0x5555569dc010) at migration/savevm.c:2467 #11 process_incoming_migration_co (opaque=0x0) at migration/migration.c:449 However later on the features are getting restored, and offloads get reset to everything supported by features: #0 qemu_set_offload (nc=0x555556a11400, csum=1, tso4=1, tso6=1, ecn=0, ufo=0) at net/net.c:474 #1 virtio_net_apply_guest_offloads (n=0x555557701ca0) at hw/net/virtio-net.c:720 #2 virtio_net_set_features (vdev=0x555557701ca0, features=5104441767) at hw/net/virtio-net.c:773 #3 virtio_set_features_nocheck (vdev=0x555557701ca0, val=5104441767) at hw/virtio/virtio.c:2052 #4 virtio_load (vdev=0x555557701ca0, f=0x5555569dc010, version_id=11) at hw/virtio/virtio.c:2220 #5 virtio_device_get (f=0x5555569dc010, opaque=0x555557701ca0, size=0, field=0x55555668cd00 <__compound_literal.5>) at hw/virtio/virtio.c:2036 #6 vmstate_load_state (f=0x5555569dc010, vmsd=0x555556577ce0 <vmstate_virtio_net>, opaque=0x555557701ca0, version_id=11) at migration/vmstate.c:143 #7 vmstate_load (f=0x5555569dc010, se=0x5555578189e0) at migration/savevm.c:829 #8 qemu_loadvm_section_start_full (f=0x5555569dc010, mis=0x5555569eee20) at migration/savevm.c:2211 #9 qemu_loadvm_state_main (f=0x5555569dc010, mis=0x5555569eee20) at migration/savevm.c:2395 #10 qemu_loadvm_state (f=0x5555569dc010) at migration/savevm.c:2467 #11 process_incoming_migration_co (opaque=0x0) at migration/migration.c:449 Fix this by preserving the state in saved_guest_offloads field and pushing out offload initialization to the new post load hook. Cc: qemu-stable@nongnu.org Signed-off-by: Mikhail Sennikovsky <mikhail.sennikovskii@cloud.ionos.com> Signed-off-by: Jason Wang <jasowang@redhat.com>

ivq/dvq/svq/free_page_vq is forgot to cleanup in virtio_balloon_device_unrealize, the memory leak stack is as follow: Direct leak of 14336 byte(s) in 2 object(s) allocated from: #0 0x7f99fd9d8560 in calloc (/usr/lib64/libasan.so.3+0xc7560) #1 0x7f99fcb20015 in g_malloc0 (/usr/lib64/libglib-2.0.so.0+0x50015) #2 0x557d90638437 in virtio_add_queue hw/virtio/virtio.c:2327 #3 0x557d9064401d in virtio_balloon_device_realize hw/virtio/virtio-balloon.c:793 #4 0x557d906356f7 in virtio_device_realize hw/virtio/virtio.c:3504 #5 0x557d9073f081 in device_set_realized hw/core/qdev.c:876 #6 0x557d908b1f4d in property_set_bool qom/object.c:2080 #7 0x557d908b655e in object_property_set_qobject qom/qom-qobject.c:26 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Message-Id: <1575444716-17632-2-git-send-email-pannengyuan@huawei.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com>

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>

Receive/transmit/event vqs forgot to cleanup in vhost_vsock_unrealize. This patch save receive/transmit vq pointer in realize() and cleanup vqs through those vq pointers in unrealize(). The leak stack is as follow: Direct leak of 21504 byte(s) in 3 object(s) allocated from: #0 0x7f86a1356970 (/lib64/libasan.so.5+0xef970) ??:? #1 0x7f86a09aa49d (/lib64/libglib-2.0.so.0+0x5249d) ??:? #2 0x5604852f85ca (./x86_64-softmmu/qemu-system-x86_64+0x2c3e5ca) /mnt/sdb/qemu/hw/virtio/virtio.c:2333 #3 0x560485356208 (./x86_64-softmmu/qemu-system-x86_64+0x2c9c208) /mnt/sdb/qemu/hw/virtio/vhost-vsock.c:339 #4 0x560485305a17 (./x86_64-softmmu/qemu-system-x86_64+0x2c4ba17) /mnt/sdb/qemu/hw/virtio/virtio.c:3531 #5 0x5604858e6b65 (./x86_64-softmmu/qemu-system-x86_64+0x322cb65) /mnt/sdb/qemu/hw/core/qdev.c:865 #6 0x5604861e6c41 (./x86_64-softmmu/qemu-system-x86_64+0x3b2cc41) /mnt/sdb/qemu/qom/object.c:2102 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Message-Id: <20200115062535.50644-1-pannengyuan@huawei.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Similar to other virtio device(https://patchwork.kernel.org/patch/11399237/), virtio queues forgot to delete in unrealize, and aslo error path in realize, this patch fix these memleaks, the leak stack is as follow: Direct leak of 57344 byte(s) in 1 object(s) allocated from: #0 0x7f15784fb970 in __interceptor_calloc (/lib64/libasan.so.5+0xef970) #1 0x7f157790849d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5249d) #2 0x55587a1bf859 in virtio_add_queue /mnt/sdb/qemu-new/qemu_test/qemu/hw/virtio/virtio.c:2333 #3 0x55587a2071d5 in vuf_device_realize /mnt/sdb/qemu-new/qemu_test/qemu/hw/virtio/vhost-user-fs.c:212 #4 0x55587a1ae360 in virtio_device_realize /mnt/sdb/qemu-new/qemu_test/qemu/hw/virtio/virtio.c:3531 #5 0x55587a63fb7b in device_set_realized /mnt/sdb/qemu-new/qemu_test/qemu/hw/core/qdev.c:891 #6 0x55587acf03f5 in property_set_bool /mnt/sdb/qemu-new/qemu_test/qemu/qom/object.c:2238 #7 0x55587acfce0d in object_property_set_qobject /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qobject.c:26 #8 0x55587acf5c8c in object_property_set_bool /mnt/sdb/qemu-new/qemu_test/qemu/qom/object.c:1390 #9 0x55587a8e22a2 in pci_qdev_realize /mnt/sdb/qemu-new/qemu_test/qemu/hw/pci/pci.c:2095 #10 0x55587a63fb7b in device_set_realized /mnt/sdb/qemu-new/qemu_test/qemu/hw/core/qdev.c:891 #11 0x55587acf03f5 in property_set_bool /mnt/sdb/qemu-new/qemu_test/qemu/qom/object.c:2238 #12 0x55587acfce0d in object_property_set_qobject /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qobject.c:26 #13 0x55587acf5c8c in object_property_set_bool /mnt/sdb/qemu-new/qemu_test/qemu/qom/object.c:1390 #14 0x55587a496d65 in qdev_device_add /mnt/sdb/qemu-new/qemu_test/qemu/qdev-monitor.c:679 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20200225075554.10835-2-pannengyuan@huawei.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Similar to other virtio-deivces, ctrl_vq forgot to delete in virtio_crypto_device_unrealize, this patch fix it. This device has aleardy maintained vq pointers. Thus, we use the new virtio_delete_queue function directly to do the cleanup. The leak stack: Direct leak of 10752 byte(s) in 3 object(s) allocated from: #0 0x7f4c024b1970 in __interceptor_calloc (/lib64/libasan.so.5+0xef970) #1 0x7f4c018be49d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5249d) #2 0x55a2f8017279 in virtio_add_queue /mnt/sdb/qemu-new/qemu_test/qemu/hw/virtio/virtio.c:2333 #3 0x55a2f8057035 in virtio_crypto_device_realize /mnt/sdb/qemu-new/qemu_test/qemu/hw/virtio/virtio-crypto.c:814 #4 0x55a2f8005d80 in virtio_device_realize /mnt/sdb/qemu-new/qemu_test/qemu/hw/virtio/virtio.c:3531 #5 0x55a2f8497d1b in device_set_realized /mnt/sdb/qemu-new/qemu_test/qemu/hw/core/qdev.c:891 #6 0x55a2f8b48595 in property_set_bool /mnt/sdb/qemu-new/qemu_test/qemu/qom/object.c:2238 #7 0x55a2f8b54fad in object_property_set_qobject /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qobject.c:26 #8 0x55a2f8b4de2c in object_property_set_bool /mnt/sdb/qemu-new/qemu_test/qemu/qom/object.c:1390 #9 0x55a2f80609c9 in virtio_crypto_pci_realize /mnt/sdb/qemu-new/qemu_test/qemu/hw/virtio/virtio-crypto-pci.c:58 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Cc: "Gonglei (Arei)" <arei.gonglei@huawei.com> Message-Id: <20200225075554.10835-5-pannengyuan@huawei.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

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>

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>

Receive/transmit/event vqs forgot to cleanup in vhost_vsock_unrealize. This patch save receive/transmit vq pointer in realize() and cleanup vqs through those vq pointers in unrealize(). The leak stack is as follow: Direct leak of 21504 byte(s) in 3 object(s) allocated from: #0 0x7f86a1356970 (/lib64/libasan.so.5+0xef970) ??:? #1 0x7f86a09aa49d (/lib64/libglib-2.0.so.0+0x5249d) ??:? #2 0x5604852f85ca (./x86_64-softmmu/qemu-system-x86_64+0x2c3e5ca) /mnt/sdb/qemu/hw/virtio/virtio.c:2333 #3 0x560485356208 (./x86_64-softmmu/qemu-system-x86_64+0x2c9c208) /mnt/sdb/qemu/hw/virtio/vhost-vsock.c:339 #4 0x560485305a17 (./x86_64-softmmu/qemu-system-x86_64+0x2c4ba17) /mnt/sdb/qemu/hw/virtio/virtio.c:3531 #5 0x5604858e6b65 (./x86_64-softmmu/qemu-system-x86_64+0x322cb65) /mnt/sdb/qemu/hw/core/qdev.c:865 #6 0x5604861e6c41 (./x86_64-softmmu/qemu-system-x86_64+0x3b2cc41) /mnt/sdb/qemu/qom/object.c:2102 Reported-by: Euler Robot <euler.robot@huawei.com> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com> Message-Id: <20200115062535.50644-1-pannengyuan@huawei.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

moyix self-assigned this Jun 21, 2014

moyix closed this as completed in 7d82323 Jan 6, 2016

zshu1 mentioned this issue Feb 23, 2017

my replay just end without error #141

Closed

linuxbest mentioned this issue Mar 25, 2017

can panda2 support SMP? #152

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gergelyrevay mentioned this issue Feb 15, 2018

segfault in taint2 while simple tstringsearch #262

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windhl mentioned this issue Sep 10, 2020

Segment Fault when using PyPanda for Win7 app's dynamic tracing #755

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Documentation for plugins #6

Documentation for plugins #6

moyix commented Jun 21, 2014

yizhibenpao commented Nov 23, 2014

m000 commented Dec 15, 2014

yizhibenpao commented Dec 16, 2014

moyix commented Dec 18, 2014

volpino commented Feb 26, 2015

m000 commented Feb 27, 2015

moyix commented Feb 27, 2015

phulin commented Feb 27, 2015

Documentation for plugins #6

Documentation for plugins #6

Comments

moyix commented Jun 21, 2014

yizhibenpao commented Nov 23, 2014

m000 commented Dec 15, 2014

yizhibenpao commented Dec 16, 2014

moyix commented Dec 18, 2014

volpino commented Feb 26, 2015

m000 commented Feb 27, 2015

moyix commented Feb 27, 2015

phulin commented Feb 27, 2015