Re: [Qemu-devel] [RFC PATCH V6 05/18] protect TBContext with tb_lock.

[Paolo Bonzini]

On 26/06/2015 16:47, fred.kon...@greensocs.com wrote:
> @@ -273,8 +274,9 @@ static TranslationBlock *tb_find_slow(CPUArchState *env,
>      ptb1 = &tcg_ctx.tb_ctx.tb_phys_hash[h];
>      for(;;) {
>          tb = *ptb1;
> -        if (!tb)
> -            goto not_found;
> +        if (!tb) {
> +            return tb;
> +        }

You are dereferencing tb outside the lock. You need a
smp_read_barrier_depends() here, and a smp_wmb() at the beginning of
tb_link_page.

Paolo

>          if (tb->pc == pc &&