This adds a generic definition of compat_sys_ptrace that calls
compat_arch_ptrace, parallel to sys_ptrace/arch_ptrace.  Some
machines needing this already define a function by that name.
The new generic function is defined only on machines that
put #define __ARCH_WANT_COMPAT_SYS_PTRACE into asm/ptrace.h.

Signed-off-by: Roland McGrath <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
---
 include/linux/compat.h |    7 +++++++
 kernel/ptrace.c        |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/include/linux/compat.h b/include/linux/compat.h
index e70a2a1..aa3a55e 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -275,5 +275,12 @@ extern int compat_ptrace_request(struct task_struct *child,
                                 compat_long_t request,
                                 compat_ulong_t addr, compat_ulong_t data);
 
+#ifdef __ARCH_WANT_COMPAT_SYS_PTRACE
+extern long compat_arch_ptrace(struct task_struct *child, compat_long_t 
request,
+                              compat_ulong_t addr, compat_ulong_t data);
+asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
+                                 compat_long_t addr, compat_long_t data);
+#endif /* __ARCH_WANT_COMPAT_SYS_PTRACE */
+
 #endif /* CONFIG_COMPAT */
 #endif /* _LINUX_COMPAT_H */
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index bc1a764..319ab4a 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -642,4 +642,50 @@ int compat_ptrace_request(struct task_struct *child, 
compat_long_t request,
 
        return ret;
 }
+
+#ifdef __ARCH_WANT_COMPAT_SYS_PTRACE
+asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
+                                 compat_long_t addr, compat_long_t data)
+{
+       struct task_struct *child;
+       long ret;
+
+       /*
+        * This lock_kernel fixes a subtle race with suid exec
+        */
+       lock_kernel();
+       if (request == PTRACE_TRACEME) {
+               ret = ptrace_traceme();
+               goto out;
+       }
+
+       child = ptrace_get_task_struct(pid);
+       if (IS_ERR(child)) {
+               ret = PTR_ERR(child);
+               goto out;
+       }
+
+       if (request == PTRACE_ATTACH) {
+               ret = ptrace_attach(child);
+               /*
+                * Some architectures need to do book-keeping after
+                * a ptrace attach.
+                */
+               if (!ret)
+                       arch_ptrace_attach(child);
+               goto out_put_task_struct;
+       }
+
+       ret = ptrace_check_attach(child, request == PTRACE_KILL);
+       if (!ret)
+               ret = compat_arch_ptrace(child, request, addr, data);
+
+ out_put_task_struct:
+       put_task_struct(child);
+ out:
+       unlock_kernel();
+       return ret;
+}
+#endif /* __ARCH_WANT_COMPAT_SYS_PTRACE */
+
 #endif /* CONFIG_COMPAT */
-- 
1.5.3.6

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