ARM: dts: at91: sama5d3: define clock rate range for tcb1

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / kernel / ptrace.c

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index bb6db48..da8c358 100644 (file)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -45,9 +45,7 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
  */
 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
 {
-       rcu_read_lock();
-       __ptrace_link(child, new_parent, __task_cred(new_parent));
-       rcu_read_unlock();
+       __ptrace_link(child, new_parent, current_cred());
 }
 
 /**
@@ -292,6 +290,16 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
        return -EPERM;
 ok:
        rcu_read_unlock();
+       /*
+        * If a task drops privileges and becomes nondumpable (through a syscall
+        * like setresuid()) while we are trying to access it, we must ensure
+        * that the dumpability is read after the credentials; otherwise,
+        * we may be able to attach to a task that we shouldn't be able to
+        * attach to (as if the task had dropped privileges without becoming
+        * nondumpable).
+        * Pairs with a write barrier in commit_creds().
+        */
+       smp_rmb();
        mm = task->mm;
        if (mm &&
            ((get_dumpable(mm) != SUID_DUMP_USER) &&