Re: [Qemu-devel] [PATCH v2] ppc / sparc: Add a tester for checking whether OpenBIOS runs successfully

[Mark Cave-Ayland]

On 17/06/16 07:07, David Gibson wrote:

> On Wed, Jun 15, 2016 at 01:10:18PM +1000, David Gibson wrote:
>> On Tue, Jun 14, 2016 at 03:57:56PM +0200, Thomas Huth wrote:
>>> Since the mac99 and g3beige PowerPC machines recently broke without
>>> being noticed, it would be good to have a tester for "make check"
>>> that detects such issues immediately. A simple way to test the firmware
>>> of these machines is to use the "-prom-env" parameter of QEMU. This
>>> parameter can be used to put some Forth code into the 'boot-command'
>>> firmware variable which then can signal success to the tester by
>>> writing a magic value to a known memory location. And since some of the
>>> Sparc machines are also using OpenBIOS, they are now tested with this
>>> prom-env-tester, too.
>>>
>>> Reviewed-by: Markus Armbruster <address@hidden>
>>> Signed-off-by: Thomas Huth <address@hidden>
>>> ---
>>>  v2: Removed unnecessary include statements (as suggested by Markus)
>>
>> Beautiful, I've applied this to ppc-for-2.7, assuming I don't get an
>> objection to taking this through my tree.
> 
> Ugh.. turns out this fails on sparc64 target on a 32-bit x86 host.
> Specifically it trips the tcg_abort() at the end of tcg_reg_alloc()
> (tcg/tcg.c).
> 
> I'm reasonably confident this is a pre-existing bug, just triggered by
> this test, but in the interests of getting this up and running on the
> platforms where it is working, I've disabled the testcase on sparc64
> for now.
> 
> Mark, if you could debug the sparc64-on-i386 failure at some point,
> that would be helpful.

I'm a little tied up until next week, however I was able to reproduce on
a local i386 VM and get a stack trace:


$ gdb --args ./qemu-system-sparc64 -nographic
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Reading symbols from ./qemu-system-sparc64...done.
(gdb) r
Starting program: /home/build/rel-qemu-git/bin/qemu-system-sparc64
-nographic
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
[New Thread 0xb7989b40 (LWP 27497)]
[New Thread 0xb4af1b40 (LWP 27498)]
OpenBIOS for Sparc64
Configuration device id QEMU version 1 machine id 0
kernel cmdline
CPUs: 1 x SUNW,UltraSPARC-IIi
UUID: 00000000-0000-0000-0000-000000000000
/home/build/src/qemu/tcg/tcg.c:1743: tcg fatal error

Program received signal SIGABRT, Aborted.
[Switching to Thread 0xb4af1b40 (LWP 27498)]
0xb7fdadad in __kernel_vsyscall ()
(gdb) bt
#0  0xb7fdadad in __kernel_vsyscall ()
#1  0xb7a2ee26 in __GI_raise (sig=6) at
../sysdeps/unix/sysv/linux/raise.c:55
#2  0xb7a303f7 in __GI_abort () at abort.c:89
#3  0x08061776 in tcg_reg_alloc (s=0x8637780 <tcg_ctx>,
desired_regs=255, allocated_regs=255, rev=true) at
/home/build/src/qemu/tcg/tcg.c:1743
#4  0x0806181a in temp_load (s=0x8637780 <tcg_ctx>, ts=0x8637978
<tcg_ctx+504>, desired_regs=255, allocated_regs=255) at
/home/build/src/qemu/tcg/tcg.c:1762
#5  0x080615e0 in tcg_reg_sync (s=0x8637780 <tcg_ctx>, reg=TCG_REG_EAX,
allocated_regs=255) at /home/build/src/qemu/tcg/tcg.c:1694
#6  0x08061653 in tcg_reg_free (s=0x8637780 <tcg_ctx>, reg=TCG_REG_EAX,
allocated_regs=254) at /home/build/src/qemu/tcg/tcg.c:1709
#7  0x08061740 in tcg_reg_alloc (s=0x8637780 <tcg_ctx>,
desired_regs=255, allocated_regs=254, rev=true) at
/home/build/src/qemu/tcg/tcg.c:1738
#8  0x0806181a in temp_load (s=0x8637780 <tcg_ctx>, ts=0x8637978
<tcg_ctx+504>, desired_regs=255, allocated_regs=254) at
/home/build/src/qemu/tcg/tcg.c:1762
#9  0x080615e0 in tcg_reg_sync (s=0x8637780 <tcg_ctx>, reg=TCG_REG_ECX,
allocated_regs=254) at /home/build/src/qemu/tcg/tcg.c:1694
#10 0x08061653 in tcg_reg_free (s=0x8637780 <tcg_ctx>, reg=TCG_REG_ECX,
allocated_regs=252) at /home/build/src/qemu/tcg/tcg.c:1709
#11 0x08061740 in tcg_reg_alloc (s=0x8637780 <tcg_ctx>,
desired_regs=255, allocated_regs=252, rev=true) at
/home/build/src/qemu/tcg/tcg.c:1738
#12 0x0806181a in temp_load (s=0x8637780 <tcg_ctx>, ts=0x8637978
<tcg_ctx+504>, desired_regs=255, allocated_regs=252) at
/home/build/src/qemu/tcg/tcg.c:1762
#13 0x08061858 in temp_load (s=0x8637780 <tcg_ctx>, ts=0x8637f48
<tcg_ctx+1992>, desired_regs=255, allocated_regs=252) at
/home/build/src/qemu/tcg/tcg.c:1765
#14 0x0806220f in tcg_reg_alloc_op (s=0x8637780 <tcg_ctx>, def=0x859c150
<tcg_op_defs+720>, opc=INDEX_op_sub2_i32, args=0x863be54
<tcg_ctx+18132>, dead_args=60, sync_args=0 '\000') at
/home/build/src/qemu/tcg/tcg.c:2050
#15 0x08063156 in tcg_gen_code (s=0x8637780 <tcg_ctx>, tb=0xb4b14d90) at
/home/build/src/qemu/tcg/tcg.c:2454
#16 0x08058cb4 in tb_gen_code (cpu=0x8a9e370, pc=4291901680,
cs_base=4291901684, flags=7, cflags=0) at
/home/build/src/qemu/translate-all.c:1212
#17 0x0805a8c5 in tb_find_slow (cpu=0x8a9e370, pc=4291901680,
cs_base=4291901684, flags=7) at /home/build/src/qemu/cpu-exec.c:310
#18 0x0805aa1e in tb_find_fast (cpu=0x8a9e370, last_tb=0xb4af1044,
tb_exit=1) at /home/build/src/qemu/cpu-exec.c:339
#19 0x0805b189 in cpu_sparc_exec (cpu=0x8a9e370) at
/home/build/src/qemu/cpu-exec.c:625
#20 0x0808666d in tcg_cpu_exec (cpu=0x8a9e370) at
/home/build/src/qemu/cpus.c:1541
#21 0x0808675b in tcg_exec_all () at /home/build/src/qemu/cpus.c:1574
#22 0x08085c29 in qemu_tcg_cpu_thread_fn (arg=0x8a9e370) at
/home/build/src/qemu/cpus.c:1171
#23 0xb7bc12de in start_thread (arg=0xb4af1b40) at pthread_create.c:334
#24 0xb7aeb23e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:122
(gdb)


I've added Richard as CC since it looks like this is something in the
TCG core.


ATB,

Mark.