[Qemu-ppc] [PATCH 1/1] target-ppc, tcg: fix usermode segfault with pthread From: Sam Bobroff Subject: [Qemu-ppc] [PATCH 1/1] target-ppc, tcg: fix usermode segfault with pthread_create() Date: Mon, 30 Jan 2017 16:08:07 +1100 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 Upstream-Status: Backport --- linux-user/main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/linux-user/main.c b/linux-user/main.c index 30049581ef..b5dee01541 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -1712,18 +1712,20 @@ 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)) { + env->nip -= 4; /* Returning from a successful sigreturn syscall. Avoid corrupting register state. */ break; } - env->nip += 4; if (ret > (target_ulong)(-515)) { env->crf[0] |= 0x1; ret = -ret;