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[Qemu-devel] [PATCH 1/4] linux-user: Disallow setting newsp for fork
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 1/4] linux-user: Disallow setting newsp for fork |
Date: |
Mon, 30 Jul 2018 16:15:50 -0400 |
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 <address@hidden>
---
linux-user/syscall.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
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
--
2.17.1