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Re: [Qemu-ppc] [PATCH v2 1/1] target-ppc, tcg: fix usermode segfault wit
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-ppc] [PATCH v2 1/1] target-ppc, tcg: fix usermode segfault with pthread_create() |
Date: |
Tue, 7 Feb 2017 12:00:48 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 |
Le 07/02/2017 à 04:21, Sam Bobroff a écrit :
> Programs run under qemu-ppc64 on an x86_64 host currently segfault
> if they use pthread_create() due to the adjustment made to the NIP in
> commit bd6fefe71cec5a0c7d2be4ac96307f25db56abf9.
>
> This patch changes cpu_loop() to set the NIP back to the
> pre-incremented value before calling do_syscall(), which causes the
> correct address to be used for the new thread and corrects the fault.
>
> Signed-off-by: Sam Bobroff <address@hidden>
> ---
>
> v2:
>
> * Remove the NIP adjustment from the -TARGET_QEMU_ESIGRETURN case, it must
> break out with the same NIP as do_syscall().
>
> linux-user/main.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 30049581ef..4ea49f68be 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -1712,10 +1712,12 @@ void cpu_loop(CPUPPCState *env)
> * in syscalls.
> */
> env->crf[0] &= ~0x1;
> + env->nip += 4;
> ret = do_syscall(env, env->gpr[0], env->gpr[3], env->gpr[4],
> env->gpr[5], env->gpr[6], env->gpr[7],
> env->gpr[8], 0, 0);
> if (ret == -TARGET_ERESTARTSYS) {
> + env->nip -= 4;
> break;
> }
> if (ret == (target_ulong)(-TARGET_QEMU_ESIGRETURN)) {
> @@ -1723,7 +1725,6 @@ void cpu_loop(CPUPPCState *env)
> Avoid corrupting register state. */
> break;
> }
> - env->nip += 4;
> if (ret > (target_ulong)(-515)) {
> env->crf[0] |= 0x1;
> ret = -ret;
>
Reviewed-by: Laurent Vivier <address@hidden>
[my comments on previous patch were inaccurate]
Thanks,
Laurent