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X-Received-From: 2607:f8b0:400c:c08::243 Subject: [Qemu-devel] [PATCH 1/4] linux-user: Disallow setting newsp for fork X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.cave-ayland@ilande.co.uk, alex.bennee@linaro.org, laurent@vivier.eu, atar4qemu@gmail.com Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" Or really, just clone devolving into fork. This should not ever happen in practice. We do want to reserve calling cpu_clone_regs for the case in which we are actually performing a clone. Signed-off-by: Richard Henderson --- linux-user/syscall.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) -- 2.17.1 Reviewed-by: Alex Bennée diff --git a/linux-user/syscall.c b/linux-user/syscall.c index dfc851cc35..5bf8d13de7 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -6502,10 +6502,14 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp, pthread_mutex_destroy(&info.mutex); pthread_mutex_unlock(&clone_lock); } else { - /* if no CLONE_VM, we consider it is a fork */ + /* If no CLONE_VM, we consider it is a fork. */ if (flags & CLONE_INVALID_FORK_FLAGS) { return -TARGET_EINVAL; } + /* As a fork, setting a new sp does not make sense. */ + if (newsp) { + return -TARGET_EINVAL; + } /* We can't support custom termination signals */ if ((flags & CSIGNAL) != TARGET_SIGCHLD) { @@ -6520,7 +6524,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp, ret = fork(); if (ret == 0) { /* Child Process. */ - cpu_clone_regs(env, newsp); fork_end(1); /* There is a race condition here. The parent process could theoretically read the TID in the child process before the child