From: "Alex Bennée" <alex.bennee@linaro.org>
To: Pranith Kumar <bobby.prani@gmail.com>
Cc: MTTCG Devel <mttcg@listserver.greensocs.com>,
Paolo Bonzini <pbonzini@redhat.com>,
alvise rigo <a.rigo@virtualopensystems.com>,
QEMU Developers <qemu-devel@nongnu.org>,
KONRAD Frederic <fred.konrad@greensocs.com>
Subject: Re: [Qemu-devel] Status of my hacks on the MTTCG WIP branch
Date: Thu, 14 Jan 2016 13:10:23 +0000 [thread overview]
Message-ID: <87io2wcnnk.fsf@linaro.org> (raw)
In-Reply-To: <87mvs9db8f.fsf@linaro.org>
Alex Bennée <alex.bennee@linaro.org> writes:
> Pranith Kumar <bobby.prani@gmail.com> writes:
>
>> Hi Alex,
>>
>> On Tue, Jan 12, 2016 at 12:29 PM, Alex Bennée <alex.bennee@linaro.org>
>> wrote:
>>
>>>
>> https://github.com/stsquad/qemu/tree/mttcg/multi_tcg_v8_wip_ajb_fix_locks
>>>
>>
>> I built this branch and ran an arm64 guest. It seems to be failing
>> similarly to what I reported earlier:
>>
>> #0 0x00007ffff2211cc9 in __GI_raise (sig=sig@entry=6) at
>> ../nptl/sysdeps/unix/sysv/linux/raise.c:56
>> #1 0x00007ffff22150d8 in __GI_abort () at abort.c:89
>> #2 0x000055555572014c in qemu_ram_addr_from_host_nofail
>> (ptr=0xffffffc000187863) at /home/pranith/devops/code/qemu/cputlb.c:357
>> #3 0x00005555557209dd in get_page_addr_code (env1=0x555556702058,
>> addr=18446743798833248356) at /home/pranith/devops/code/qemu/cputlb.c:568
>> #4 0x00005555556db98c in tb_find_physical (cpu=0x5555566f9dd0,
>> pc=18446743798833248356, cs_base=0, flags=18446744071830503424) at
>> /home/pranith/devops/code/qemu/cpu-exec.c:224
>> #5 0x00005555556dbaf4 in tb_find_slow (cpu=0x5555566f9dd0,
>> pc=18446743798833248356, cs_base=0, flags=18446744071830503424) at
>> /home/pranith/devops/code/qemu/cpu-exec.c:268
>> #6 0x00005555556dbc77 in tb_find_fast (cpu=0x5555566f9dd0) at
>> /home/pranith/devops/code/qemu/cpu-exec.c:311
>> #7 0x00005555556dc0f1 in cpu_arm_exec (cpu=0x5555566f9dd0) at
>> /home/pranith/devops/code/qemu/cpu-exec.c:492
>> #8 0x00005555557050ee in tcg_cpu_exec (cpu=0x5555566f9dd0) at
>> /home/pranith/devops/code/qemu/cpus.c:1486
>> #9 0x00005555557051af in tcg_exec_all (cpu=0x5555566f9dd0) at
>> /home/pranith/devops/code/qemu/cpus.c:1515
>> #10 0x0000555555704800 in qemu_tcg_cpu_thread_fn (arg=0x5555566f9dd0) at
>> /home/pranith/devops/code/qemu/cpus.c:1187
>> #11 0x00007ffff25a8182 in start_thread (arg=0x7fffd20c8700) at
>> pthread_create.c:312
>> #12 0x00007ffff22d547d in clone () at
>> ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
<snip>
Having seen a backtrace of a crash while the other thread was flushing
the TLB entries I sprinkled a bunch of:
g_assert(cpu == current_cpu);
In all public functions in cputlb that took a CPU. There are a bunch of
cases that don't defer actions across CPUs which need to be fixed up. I
suspect they don't hit in the arm case because the type of TLB flushing
pattern is different. In aarch64 it my backtrace it was triggered by
tlbi_aa64_vae1is_write:
7 Thread 0x7ffe777fe700 (LWP 32705) "worker" sem_timedwait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S:101
6 Thread 0x7ffe77fff700 (LWP 32704) "worker" sem_timedwait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S:101
5 Thread 0x7fff8d9d0700 (LWP 32703) "CPU 1/TCG" 0x000055555572cc18 in memcpy (__len=8, __src=<synthetic pointer>, __dest=<optimised out>)
at /usr/include/x86_64-linux-gnu/bits/string3.h:51
* 4 Thread 0x7fff8e1d1700 (LWP 32702) "CPU 0/TCG" memset () at ../sysdeps/x86_64/memset.S:94
3 Thread 0x7fff8f1cb700 (LWP 32701) "worker" sem_timedwait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S:101
2 Thread 0x7fffe45c8700 (LWP 32700) "qemu-system-aar" syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
1 Thread 0x7ffff7f98c00 (LWP 32696) "qemu-system-aar" 0x00007ffff0ba01ef in __GI_ppoll (fds=0x5555575cb5b0, nfds=8, timeout=<optimised out>,
timeout@entry=0x7fffffffdf60, sigmask=sigmask@entry=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:56
#0 memset () at ../sysdeps/x86_64/memset.S:94
#1 0x0000555555728bee in memset (__len=32768, __ch=0, __dest=0x555556632568) at /usr/include/x86_64-linux-gnu/bits/string3.h:84
#2 v_tlb_flush_by_mmuidx (argp=0x7fff8e1d0430, cpu=0x555556632380) at /home/alex/lsrc/qemu/qemu.git/cputlb.c:136
#3 tlb_flush_page_by_mmuidx (cpu=cpu@entry=0x555556632380, addr=addr@entry=547976253440) at /home/alex/lsrc/qemu/qemu.git/cputlb.c:243
#4 0x00005555557fcb4a in tlbi_aa64_vae1is_write (env=<optimised out>, ri=<optimised out>, value=<optimised out>)
at /home/alex/lsrc/qemu/qemu.git/target-arm/helper.c:2757
#5 0x00007fffa441dac5 in code_gen_buffer ()
#6 0x00005555556eef4b in cpu_tb_exec (tb_ptr=<optimised out>, cpu=0x5555565eddd0) at /home/alex/lsrc/qemu/qemu.git/cpu-exec.c:157
#7 cpu_arm_exec (cpu=cpu@entry=0x5555565eddd0) at /home/alex/lsrc/qemu/qemu.git/cpu-exec.c:520
#8 0x00005555557108e8 in tcg_cpu_exec (cpu=0x5555565eddd0) at /home/alex/lsrc/qemu/qemu.git/cpus.c:1486
#9 tcg_exec_all (cpu=0x5555565eddd0) at /home/alex/lsrc/qemu/qemu.git/cpus.c:1515
#10 qemu_tcg_cpu_thread_fn (arg=0x5555565eddd0) at /home/alex/lsrc/qemu/qemu.git/cpus.c:1187
#11 0x00007ffff0e80182 in start_thread (arg=0x7fff8e1d1700) at pthread_create.c:312
#12 0x00007ffff0bad47d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
[Switching to thread 5 (Thread 0x7fff8d9d0700 (LWP 32703))]
#0 0x000055555572cc18 in memcpy (__len=8, __src=<synthetic pointer>, __dest=<optimised out>) at /usr/include/x86_64-linux-gnu/bits/string3.h:51
51 return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
#0 0x000055555572cc18 in memcpy (__len=8, __src=<synthetic pointer>, __dest=<optimised out>) at /usr/include/x86_64-linux-gnu/bits/string3.h:51
#1 stq_he_p (v=<optimised out>, ptr=<optimised out>) at /home/alex/lsrc/qemu/qemu.git/include/qemu/bswap.h:292
#2 stq_le_p (v=547973099520, ptr=<optimised out>) at /home/alex/lsrc/qemu/qemu.git/include/qemu/bswap.h:327
#3 helper_le_stq_mmu (env=0x55555663a608, addr=18446743801961580216, val=547973099520, oi=<optimised out>, retaddr=140735948385557)
at /home/alex/lsrc/qemu/qemu.git/softmmu_template.h:455
#4 0x00007fffa435ed17 in code_gen_buffer ()
#5 0x00005555556eef4b in cpu_tb_exec (tb_ptr=<optimised out>, cpu=0x555556632380) at /home/alex/lsrc/qemu/qemu.git/cpu-exec.c:157
#6 cpu_arm_exec (cpu=cpu@entry=0x555556632380) at /home/alex/lsrc/qemu/qemu.git/cpu-exec.c:520
#7 0x00005555557108e8 in tcg_cpu_exec (cpu=0x555556632380) at /home/alex/lsrc/qemu/qemu.git/cpus.c:1486
#8 tcg_exec_all (cpu=0x555556632380) at /home/alex/lsrc/qemu/qemu.git/cpus.c:1515
#9 qemu_tcg_cpu_thread_fn (arg=0x555556632380) at /home/alex/lsrc/qemu/qemu.git/cpus.c:1187
#10 0x00007ffff0e80182 in start_thread (arg=0x7fff8d9d0700) at pthread_create.c:312
#11 0x00007ffff0bad47d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
A debugging session is active.
Needless to say anything messing with structures used by the other
threads needs to take great care or doom will occur ;-)
I'll look at fixing them up in my tree while Fred finishes his re-base.
--
Alex Bennée
next prev parent reply other threads:[~2016-01-14 13:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-12 17:29 [Qemu-devel] Status of my hacks on the MTTCG WIP branch Alex Bennée
2016-01-12 20:23 ` Pranith Kumar
2016-01-13 10:28 ` Alex Bennée
2016-01-14 13:10 ` Alex Bennée [this message]
2016-01-14 13:12 ` KONRAD Frederic
2016-01-14 13:58 ` Alex Bennée
2016-01-15 13:53 ` Alex Bennée
2016-01-15 14:24 ` Pranith Kumar
2016-01-15 14:30 ` KONRAD Frederic
2016-01-15 14:46 ` Alex Bennée
2016-01-15 14:49 ` KONRAD Frederic
2016-01-15 16:02 ` Paolo Bonzini
2016-01-15 14:32 ` alvise rigo
2016-01-15 14:51 ` Alex Bennée
2016-01-15 15:08 ` alvise rigo
2016-01-15 15:25 ` Alex Bennée
2016-01-15 16:34 ` alvise rigo
2016-01-15 16:59 ` Alex Bennée
2016-01-18 19:09 ` Alex Bennée
2016-01-19 8:31 ` alvise rigo
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