Re: [Qemu-devel] Status of my hacks on the MTTCG WIP branch

[KONRAD Frederic <fred.konrad@greensocs.com>]

Le 14/01/2016 14:10, Alex Bennée a écrit :
> 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
Hi,

Is that possible those one have been added since the V7 version?
I saw some changes there.

Thanks,
Fred