5 files changed, 27 insertions, 27 deletions

diff --git a/arch/um/include/shared/skas/stub-data.h b/arch/um/include/shared/skas/stub-data.h
index 6b01d97a9386..5e3ade3fb38b 100644
--- a/arch/um/include/shared/skas/stub-data.h
+++ b/arch/um/include/shared/skas/stub-data.h
@@ -11,7 +11,7 @@
 struct stub_data {
 	unsigned long offset;
 	int fd;
-	long err;
+	long parent_err, child_err;
 };
 
 #endif
diff --git a/arch/um/kernel/skas/clone.c b/arch/um/kernel/skas/clone.c
index bfb70c456b30..7c592c788cbf 100644
--- a/arch/um/kernel/skas/clone.c
+++ b/arch/um/kernel/skas/clone.c
@@ -24,29 +24,26 @@
 void __attribute__ ((__section__ (".__syscall_stub")))
 stub_clone_handler(void)
 {
-	struct stub_data *data = (struct stub_data *) STUB_DATA;
+	int stack;
+	struct stub_data *data = (void *) ((unsigned long)&stack & ~(UM_KERN_PAGE_SIZE - 1));
 	long err;
 
 	err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
-			    STUB_DATA + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
-	if (err != 0)
-		goto out;
+			    (unsigned long)data + UM_KERN_PAGE_SIZE / 2 - sizeof(void *));
+	if (err) {
+		data->parent_err = err;
+		goto done;
+	}
 
 	err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
-	if (err)
-		goto out;
+	if (err) {
+		data->child_err = err;
+		goto done;
+	}
 
 	remap_stack(data->fd, data->offset);
 	goto done;
 
- out:
-	/*
-	 * save current result.
-	 * Parent: pid;
-	 * child: retcode of mmap already saved and it jumps around this
-	 * assignment
-	 */
-	data->err = err;
  done:
 	trap_myself();
 }
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index d910e25c273e..623b0aeadf4c 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -545,8 +545,14 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 	 * and child's mmap2 calls
 	 */
 	*data = ((struct stub_data) {
-			.offset	= MMAP_OFFSET(new_offset),
-			.fd     = new_fd
+		.offset	= MMAP_OFFSET(new_offset),
+		.fd     = new_fd,
+		.parent_err = -ESRCH,
+		.child_err = 0,
+	});
+
+	*child_data = ((struct stub_data) {
+		.child_err = -ESRCH,
 	});
 
 	err = ptrace_setregs(pid, thread_regs);
@@ -564,9 +570,6 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 		return err;
 	}
 
-	/* set a well known return code for detection of child write failure */
-	child_data->err = 12345678;
-
 	/*
 	 * Wait, until parent has finished its work: read child's pid from
 	 * parent's stack, and check, if bad result.
@@ -581,7 +584,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 
 	wait_stub_done(pid);
 
-	pid = data->err;
+	pid = data->parent_err;
 	if (pid < 0) {
 		printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports "
 		       "error %d\n", -pid);
@@ -593,10 +596,10 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 	 * child's stack and check it.
 	 */
 	wait_stub_done(pid);
-	if (child_data->err != STUB_DATA) {
-		printk(UM_KERN_ERR "copy_context_skas0 - stub-child reports "
-		       "error %ld\n", child_data->err);
-		err = child_data->err;
+	if (child_data->child_err != STUB_DATA) {
+		printk(UM_KERN_ERR "copy_context_skas0 - stub-child %d reports "
+		       "error %ld\n", pid, data->child_err);
+		err = data->child_err;
 		goto out_kill;
 	}
 
diff --git a/arch/x86/um/shared/sysdep/stub_32.h b/arch/x86/um/shared/sysdep/stub_32.h
index 51fd256c75f0..8ea69211e53c 100644
--- a/arch/x86/um/shared/sysdep/stub_32.h
+++ b/arch/x86/um/shared/sysdep/stub_32.h
@@ -86,7 +86,7 @@ static inline void remap_stack(int fd, unsigned long offset)
 			    "d" (PROT_READ | PROT_WRITE),
 			    "S" (MAP_FIXED | MAP_SHARED), "D" (fd),
 			    "a" (offset),
-			    "i" (&((struct stub_data *) STUB_DATA)->err)
+			    "i" (&((struct stub_data *) STUB_DATA)->child_err)
 			  : "memory");
 }
 
diff --git a/arch/x86/um/shared/sysdep/stub_64.h b/arch/x86/um/shared/sysdep/stub_64.h
index 994df93c5ed3..b7b8b8e4359d 100644
--- a/arch/x86/um/shared/sysdep/stub_64.h
+++ b/arch/x86/um/shared/sysdep/stub_64.h
@@ -92,7 +92,7 @@ static inline void remap_stack(long fd, unsigned long offset)
 			    "d" (PROT_READ | PROT_WRITE),
                             "g" (MAP_FIXED | MAP_SHARED), "g" (fd),
 			    "g" (offset),
-			    "i" (&((struct stub_data *) STUB_DATA)->err)
+			    "i" (&((struct stub_data *) STUB_DATA)->child_err)
 			  : __syscall_clobber, "r10", "r8", "r9" );
 }