commit d509eeb13c9c6fef4a29ca43c64f591d8c61d201
author Peter Maydell <peter.maydell@linaro.org> Thu May 12 18:47:52 2016 +0100
committer Riku Voipio <riku.voipio@linaro.org> Fri May 27 14:50:39 2016 +0300
tree ede370d9f0092bc24baa338bc3cdaa47a8ce0d68
parent 6df9d38d33be8397bda8838dea5a4a10d662749b

linux-user: Use safe_syscall for futex syscall

Use the safe_syscall wrapper for the futex syscall.

In particular, this fixes hangs when using programs that link
against the Boehm garbage collector, including the Mono runtime.

(We don't change the sys_futex() call in the implementation of
the exit syscall, because as the FIXME comment there notes
that should be handled by disabling signals, since we can't
easily back out if the futex were to return ERESTARTSYS.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

linux-user/syscall.c

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index c9c2ae9..4e419fb 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -697,6 +697,8 @@
 safe_syscall3(int, execve, const char *, filename, char **, argv, char **, envp)
 safe_syscall6(int, pselect6, int, nfds, fd_set *, readfds, fd_set *, writefds, \
               fd_set *, exceptfds, struct timespec *, timeout, void *, sig)
+safe_syscall6(int,futex,int *,uaddr,int,op,int,val, \
+              const struct timespec *,timeout,int *,uaddr2,int,val3)
 
 static inline int host_to_target_sock_type(int host_type)
 {
@@ -5381,12 +5383,12 @@
         } else {
             pts = NULL;
         }
-        return get_errno(sys_futex(g2h(uaddr), op, tswap32(val),
+        return get_errno(safe_futex(g2h(uaddr), op, tswap32(val),
                          pts, NULL, val3));
     case FUTEX_WAKE:
-        return get_errno(sys_futex(g2h(uaddr), op, val, NULL, NULL, 0));
+        return get_errno(safe_futex(g2h(uaddr), op, val, NULL, NULL, 0));
     case FUTEX_FD:
-        return get_errno(sys_futex(g2h(uaddr), op, val, NULL, NULL, 0));
+        return get_errno(safe_futex(g2h(uaddr), op, val, NULL, NULL, 0));
     case FUTEX_REQUEUE:
     case FUTEX_CMP_REQUEUE:
     case FUTEX_WAKE_OP:
@@ -5396,11 +5398,11 @@
            to satisfy the compiler.  We do not need to tswap TIMEOUT
            since it's not compared to guest memory.  */
         pts = (struct timespec *)(uintptr_t) timeout;
-        return get_errno(sys_futex(g2h(uaddr), op, val, pts,
-                                   g2h(uaddr2),
-                                   (base_op == FUTEX_CMP_REQUEUE
-                                    ? tswap32(val3)
-                                    : val3)));
+        return get_errno(safe_futex(g2h(uaddr), op, val, pts,
+                                    g2h(uaddr2),
+                                    (base_op == FUTEX_CMP_REQUEUE
+                                     ? tswap32(val3)
+                                     : val3)));
     default:
         return -TARGET_ENOSYS;
     }