Re: [Qemu-devel] tpm-tis-test and tpm-crb-test crash on OSX

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

On 03/16/2018 09:45 AM, Stefan Berger wrote:
> On 03/16/2018 09:41 AM, Marc-André Lureau wrote:
>> Hi
>>
>> On Fri, Mar 16, 2018 at 2:37 PM, Marc-André Lureau
>> <marcandre.lureau@gmail.com> wrote:
>>> Hi
>>>
>>> On Fri, Mar 16, 2018 at 2:27 PM, Daniel P. Berrangé 
>>> <berrange@redhat.com> wrote:
>>>> On Fri, Mar 16, 2018 at 01:24:53PM +0000, Peter Maydell wrote:
>>>>> On 16 March 2018 at 13:12, Peter Maydell 
>>>>> <peter.maydell@linaro.org> wrote:
>>>>>> On OSX host, I noticed that tpm-tis-test and tpm-crb-test
>>>>>> both crash on OSX, hitting an error_abort case:
>>>>>>
>>>>>> (lldb) run
>>>>>> Process 65115 launched:
>>>>>> '/Users/pm215/src/qemu-for-merges/build/all/tests/tpm-tis-test'
>>>>>> (x86_64)
>>>>>> /i386/tpm-tis/test_check_localities: OK
>>>>>> /i386/tpm-tis/test_check_access_reg: OK
>>>>>> /i386/tpm-tis/test_check_access_reg_seize: OK
>>>>>> /i386/tpm-tis/test_check_access_reg_release: OK
>>>>>> /i386/tpm-tis/test_check_transmit: OK
>>>>>> Unexpected error in qio_channel_socket_readv() at
>>>>>> /Users/pm215/src/qemu-for-merges/io/channel-socket.c:494:
>>>>>> Unable to read from socket: Bad file descriptor
>>>>>>
>>>>>> Here's a backtrace from tpm-tis-test:
>>>>> Dan suggested a race condition, which prompted me to get an
>>>>> all-threads backtrace:
>>>>>
>>>>>    thread #1: tid = 0xb50f19, 0x00007fff7eb97502
>>>>> libsystem_kernel.dylib`__wait4 + 10, queue = 'com.apple.main-thread'
>>>>>      frame #0: 0x00007fff7eb97502 libsystem_kernel.dylib`__wait4 + 10
>>>>>      frame #1: 0x000000010001b303 tpm-tis-test`qtest_quit [inlined]
>>>>> kill_qemu(s=<unavailable>) + 99 at libqtest.c:107
>>>>>      frame #2: 0x000000010001b2df
>>>>> tpm-tis-test`qtest_quit(s=0x0000000100404c60) + 63 at libqtest.c:280
>>>>>      frame #3: 0x0000000100001bd1 tpm-tis-test`main [inlined] 
>>>>> qtest_end
>>>>> + 9 at libqtest.h:555
>>>>>      frame #4: 0x0000000100001bc8 
>>>>> tpm-tis-test`main(argc=<unavailable>,
>>>>> argv=<unavailable>) + 520 at tpm-tis-test.c:477
>>>>>      frame #5: 0x00007fff7ea47115 libdyld.dylib`start + 1
>>>>>      frame #6: 0x00007fff7ea47115 libdyld.dylib`start + 1
>>>>>
>>>>>    thread #3: tid = 0xb50f4a, 0x00007fff7eb977d2
>>>>> libsystem_kernel.dylib`close + 10
>>>>>      frame #0: 0x00007fff7eb977d2 libsystem_kernel.dylib`close + 10
>>>>>      frame #1: 0x0000000100007def
>>>>> tpm-tis-test`qio_channel_socket_close(ioc=<unavailable>,
>>>>> errp=0x000000010006c930) + 63 at channel-socket.c:693
>>>>>      frame #2: 0x00000001000039f9
>>>>> tpm-tis-test`tpm_emu_ctrl_thread(data=0x00007ffeefbff0e8) + 713 at
>>>>> tpm-emu.c:128
>>>>>      frame #3: 0x00000001001b2ec0 
>>>>> libglib-2.0.0.dylib`g_thread_create_proxy + 191
>>>>>      frame #4: 0x00007fff7ecd26c1 
>>>>> libsystem_pthread.dylib`_pthread_body + 340
>>>>>      frame #5: 0x00007fff7ecd256d 
>>>>> libsystem_pthread.dylib`_pthread_start + 377
>>>>>      frame #6: 0x00007fff7ecd1c5d 
>>>>> libsystem_pthread.dylib`thread_start + 13
>>>>>
>>>>> * thread #2: tid = 0xb50f50, 0x00007fff7eb96e3e
>>>>> libsystem_kernel.dylib`__pthread_kill + 10
>>>>>    * frame #0: 0x00007fff7eb96e3e 
>>>>> libsystem_kernel.dylib`__pthread_kill + 10
>>>>>      frame #1: 0x00007fff7ecd5150 
>>>>> libsystem_pthread.dylib`pthread_kill + 333
>>>>>      frame #2: 0x00007fff7eaf3312 libsystem_c.dylib`abort + 127
>>>>>      frame #3: 0x0000000100043431 tpm-tis-test`error_setv [inlined]
>>>>> error_handle_fatal(errp=<unavailable>) + 43 at error.c:38
>>>>>      frame #4: 0x0000000100043406
>>>>> tpm-tis-test`error_setv(errp=<unavailable>, src=<unavailable>,
>>>>> line=<unavailable>, func=<unavailable>,
>>>>> err_class=ERROR_CLASS_GENERIC_ERROR, fmt=<unavailable>,
>>>>> ap=<unavailable>, suffix=<unavailable>) + 246 at error.c:71
>>>>>      frame #5: 0x00000001000435db
>>>>> tpm-tis-test`error_setg_errno_internal(errp=0x000000010006c930,
>>>>> src="/Users/pm215/src/qemu-for-merges/io/channel-socket.c", line=494,
>>>>> func="qio_channel_socket_readv", os_errno=<unavailable>, fmt="Unable
>>>>> to read from socket") + 219 at error.c:111
>>>>>      frame #6: 0x0000000100007ba5
>>>>> tpm-tis-test`qio_channel_socket_readv(ioc=<unavailable>,
>>>>> iov=<unavailable>, niov=<unavailable>, fds=0x0000000000000000,
>>>>> nfds=0x0000000000000000, errp=0x000000010006c930) + 341 at
>>>>> channel-socket.c:493
>>>>>      frame #7: 0x0000000100004717 tpm-tis-test`qio_channel_read
>>>>> [inlined] qio_channel_readv_full(ioc=0x00000001007006b0,
>>>>> iov=<unavailable>, niov=1, fds=<unavailable>, nfds=<unavailable>,
>>>>> errp=0x000000010006c930) + 62 at channel.c:65
>>>>>      frame #8: 0x00000001000046d9
>>>>> tpm-tis-test`qio_channel_read(ioc=0x00000001007006b0,
>>>>> buf=<unavailable>, buflen=<unavailable>, errp=<unavailable>) + 41 at
>>>>> channel.c:216
>>>>>      frame #9: 0x0000000100003dd1
>>>>> tpm-tis-test`tpm_emu_tpm_thread(data=0x00007ffeefbff0e8) + 241 at
>>>>> tpm-emu.c:41
>>>>>      frame #10: 0x00000001001b2ec0
>>>>> libglib-2.0.0.dylib`g_thread_create_proxy + 191
>>>>>      frame #11: 0x00007fff7ecd26c1 
>>>>> libsystem_pthread.dylib`_pthread_body + 340
>>>>>      frame #12: 0x00007fff7ecd256d 
>>>>> libsystem_pthread.dylib`_pthread_start + 377
>>>>>      frame #13: 0x00007fff7ecd1c5d 
>>>>> libsystem_pthread.dylib`thread_start + 13
>>>>>
>>>>>
>>>>> My guess is that the problem here is that the tpm_emu_ctrl_thread 
>>>>> (thread 3) is
>>>>> forcibly closing the channel, which causes the tpm_emu_thread 
>>>>> (thread 2)
>>>>> to abort because its read returned an error.
>>>> At least the tpm_emu_tpm_thread() there is only something in the test
>>>> suite, so the real system emulator code isn't at risk of crashing.
>>>>
>>>> Feels like the thread simply should *not* use error_abort, and instead
>>>> have a more graceful way to exit when the socket closes
>>>>
>>> The code expects the read() to return 0 on disconnect, not an error.
>>> Apparently this works on !osx. Should we adapt qio-channel-socket to
>>> return 0 in this case on osx too?
>> Oh I see, it calls close() on the same end, that's not correct. I
>> wonder if shutdown would be better. Other suggestions?
>>
> We could send the thread a special message, like 0xff ff ff ff, and 
> that terminates it...

... wrong end of socket, so doesn't work. Other way would be to pass a 
pipe to the TPM emulator thread and have it poll on the pipefd and the 
channelfd and terminate upon pipefd reception...


>
>     Stefan
>
>