Correct crash in child processes under armeabi Android

* exec/trace.c (process_system_call) <READLINKAT_SYSCALL>:
Examine tracee->waiting_for_syscall and avoid rewriting user
arguments if a system call is presently being executed by the
kernel.  Reported by Romário Rios <romariorios@protonmail.com>.

1 files changed, 14 insertions, 8 deletions

diff --git a/exec/trace.c b/exec/trace.c
index 3b384792d0a..f9deef8eb2d 100644
--- a/exec/trace.c
+++ b/exec/trace.c
@@ -1039,16 +1039,22 @@ process_system_call (struct exec_tracee *tracee)
 #endif /* READLINK_SYSCALL */
     case READLINKAT_SYSCALL:
 
-      /* Handle this readlinkat system call.  */
-      rc = handle_readlinkat (callno, &regs, tracee,
-                              &result);
+      /* This system call is already in progress if
+         TRACEE->waiting_for_syscall is true.  */
 
-      /* rc means the same as in `handle_exec'.  */
+      if (!tracee->waiting_for_syscall)
+        {
+          /* Handle this readlinkat system call.  */
+          rc = handle_readlinkat (callno, &regs, tracee,
+                                  &result);
+
+          /* rc means the same as in `handle_exec'.  */
 
-      if (rc == 1)
-        goto report_syscall_error;
-      else if (rc == 2)
-        goto emulate_syscall;
+          if (rc == 1)
+            goto report_syscall_error;
+          else if (rc == 2)
+            goto emulate_syscall;
+        }
 
       /* Fallthrough.  */