diff mbox series

[v2,1/8] linux-user: Disallow setting newsp for fork

Message ID 20190510032710.23910-2-richard.henderson@linaro.org
State New
Headers show
Series linux-user sparc fixes | expand

Commit Message

Richard Henderson May 10, 2019, 3:27 a.m. UTC 
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.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 linux-user/syscall.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

-- 
2.17.1

Comments

Richard Henderson May 15, 2019, 12:31 a.m. UTC | #1 
On 5/9/19 8:27 PM, Richard Henderson wrote:
> 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.

> 

> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  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 96cd4bf86d..f7d0754c8d 100644

> --- a/linux-user/syscall.c

> +++ b/linux-user/syscall.c

> @@ -5553,10 +5553,14 @@ 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;

> +        }


This causes failures for aarch64 and riscv.

We have to allow no-op setting of sp as well.
Other targets set newsp to 0 for in vfork.S in glibc.


r~
diff mbox series

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 96cd4bf86d..f7d0754c8d 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5553,10 +5553,14 @@  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) {
@@ -5571,7 +5575,6 @@  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