[patch 08/37] sparc: Fix fork/clone/vfork system call restart.

[Greg KH]

2.6.25-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: David S. Miller <davem@xxxxxxxxxxxxx>

[ Upstream commit: 1e38c126c9252b612697e34f43b1b3371c8ee31d ]

We clobber %i1 as well as %i0 for these system calls,
because they give two return values.

Therefore, on error, we have to restore %i1 properly
or else the restart explodes since it uses the wrong
arguments.

This fixes glibc's nptl/tst-eintr1.c testcase.

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 arch/sparc/kernel/process.c   |   20 ++++++++++++++++----
 arch/sparc64/kernel/process.c |   18 +++++++++++++++---
 2 files changed, 31 insertions(+), 7 deletions(-)

--- a/arch/sparc64/kernel/process.c
+++ b/arch/sparc64/kernel/process.c
@@ -507,6 +507,8 @@ asmlinkage long sparc_do_fork(unsigned l
 			      unsigned long stack_size)
 {
 	int __user *parent_tid_ptr, *child_tid_ptr;
+	unsigned long orig_i1 = regs->u_regs[UREG_I1];
+	long ret;
 
 #ifdef CONFIG_COMPAT
 	if (test_thread_flag(TIF_32BIT)) {
@@ -519,9 +521,19 @@ asmlinkage long sparc_do_fork(unsigned l
 		child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
 	}
 
-	return do_fork(clone_flags, stack_start,
-		       regs, stack_size,
-		       parent_tid_ptr, child_tid_ptr);
+	ret = do_fork(clone_flags, stack_start,
+		      regs, stack_size,
+		      parent_tid_ptr, child_tid_ptr);
+
+	/* If we get an error and potentially restart the system
+	 * call, we're screwed because copy_thread() clobbered
+	 * the parent's %o1.  So detect that case and restore it
+	 * here.
+	 */
+	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
+		regs->u_regs[UREG_I1] = orig_i1;
+
+	return ret;
 }
 
 /* Copy a Sparc thread.  The fork() return value conventions
--- a/arch/sparc/kernel/process.c
+++ b/arch/sparc/kernel/process.c
@@ -421,14 +421,26 @@ asmlinkage int sparc_do_fork(unsigned lo
                              unsigned long stack_size)
 {
 	unsigned long parent_tid_ptr, child_tid_ptr;
+	unsigned long orig_i1 = regs->u_regs[UREG_I1];
+	long ret;
 
 	parent_tid_ptr = regs->u_regs[UREG_I2];
 	child_tid_ptr = regs->u_regs[UREG_I4];
 
-	return do_fork(clone_flags, stack_start,
-		       regs, stack_size,
-		       (int __user *) parent_tid_ptr,
-		       (int __user *) child_tid_ptr);
+	ret = do_fork(clone_flags, stack_start,
+		      regs, stack_size,
+		      (int __user *) parent_tid_ptr,
+		      (int __user *) child_tid_ptr);
+
+	/* If we get an error and potentially restart the system
+	 * call, we're screwed because copy_thread() clobbered
+	 * the parent's %o1.  So detect that case and restore it
+	 * here.
+	 */
+	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
+		regs->u_regs[UREG_I1] = orig_i1;
+
+	return ret;
 }
 
 /* Copy a Sparc thread.  The fork() return value conventions

-- 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/