Re: [Qemu-devel] [Qemu-arm] [PATCH v2 1/1] target/arm: Fix vector operation segfault

[Alistair Francis]

On Thu, 2019-05-16 at 07:54 +0100, Alex Bennée wrote:
> Alistair Francis <address@hidden> writes:
> 
> > Commit 89e68b575 "target/arm: Use vector operations for saturation"
> > causes this abort() when booting QEMU ARM with a Cortex-A15:
> > 
> > 0  0x00007ffff4c2382f in raise () at /usr/lib/libc.so.6
> > 1  0x00007ffff4c0e672 in abort () at /usr/lib/libc.so.6
> > 2  0x00005555559c1839 in disas_neon_data_insn (insn=<optimized
> > out>, s=<optimized out>) at ./target/arm/translate.c:6673
> > 3  0x00005555559c1839 in disas_neon_data_insn (s=<optimized out>,
> > insn=<optimized out>) at ./target/arm/translate.c:6386
> > 4  0x00005555559cd8a4 in disas_arm_insn (insn=4081107068,
> > s=0x7fffe59a9510) at ./target/arm/translate.c:9289
> > 5  0x00005555559cd8a4 in arm_tr_translate_insn
> > (dcbase=0x7fffe59a9510, cpu=<optimized out>) at
> > ./target/arm/translate.c:13612
> > 6  0x00005555558d1d39 in translator_loop (ops=0x5555561cc580
> > <arm_translator_ops>, db=0x7fffe59a9510, cpu=0x55555686a2f0,
> > tb=<optimized out>, max_insns=<optimized out>) at
> > ./accel/tcg/translator.c:96
> > 7  0x00005555559d10d4 in gen_intermediate_code (address@hidden
> > 55686a2f0, address@hidden <code_gen_buffer+126091347>, 
> > address@hidden) at ./target/arm/translate.c:13901
> > 8  0x00005555558d06b9 in tb_gen_code (address@hidden,
> > pc=3067096216, cs_base=0, flags=192, cflags=-16252928, address@hidden
> > =524288) at ./accel/tcg/translate-all.c:1736
> > 9  0x00005555558ce467 in tb_find (cf_mask=524288, tb_exit=1,
> > last_tb=0x7fffd783e640 <code_gen_buffer+126084627>, cpu=0x1) at
> > ./accel/tcg/cpu-exec.c:407
> > 10 0x00005555558ce467 in cpu_exec (address@hidden) at
> > ./accel/tcg/cpu-exec.c:728
> > 11 0x000055555588b0cf in tcg_cpu_exec (cpu=0x55555686a2f0) at
> > ./cpus.c:1431
> > 12 0x000055555588d223 in qemu_tcg_cpu_thread_fn
> > (arg=0x55555686a2f0) at ./cpus.c:1735
> > 13 0x000055555588d223 in qemu_tcg_cpu_thread_fn (address@hidden
> > 555686a2f0) at ./cpus.c:1709
> > 14 0x0000555555d2629a in qemu_thread_start (args=<optimized out>)
> > at ./util/qemu-thread-posix.c:502
> > 15 0x00007ffff4db8a92 in start_thread () at /usr/lib/libpthread.
> > 
> > This patch ensures that we don't hit the abort() in the second
> > switch
> > case in disas_neon_data_insn() as we will return from the first
> > case.
> > 
> > Signed-off-by: Alistair Francis <address@hidden>
> 
> This fixes the abort()'s I was seeing while running the qemu-iotests
> under an emulated Debian Buster armhf system so:

Great! I just send a v3 which should be plain text.

Alistair

> 
> Reviewed-by: Alex Bennée <address@hidden>
> Tested-by: Alex Bennée <address@hidden>
> 
> 
> > ---
> >  target/arm/translate.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/target/arm/translate.c b/target/arm/translate.c
> > index dd053c80d6..298c262825 100644
> > --- a/target/arm/translate.c
> > +++ b/target/arm/translate.c
> > @@ -6598,13 +6598,13 @@ static int
> > disas_neon_data_insn(DisasContext *s, uint32_t insn)
> >              tcg_gen_gvec_4(rd_ofs, offsetof(CPUARMState, vfp.qc),
> >                             rn_ofs, rm_ofs, vec_size, vec_size,
> >                             (u ? uqadd_op : sqadd_op) + size);
> > -            break;
> > +            return 0;
> > 
> >          case NEON_3R_VQSUB:
> >              tcg_gen_gvec_4(rd_ofs, offsetof(CPUARMState, vfp.qc),
> >                             rn_ofs, rm_ofs, vec_size, vec_size,
> >                             (u ? uqsub_op : sqsub_op) + size);
> > -            break;
> > +            return 0;
> > 
> >          case NEON_3R_VMUL: /* VMUL */
> >              if (u) {
> 
> --
> Alex Bennée