latent_entropy: Mark functions with __latent_entropy

[cascardo/linux.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 52e725d..0539388 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -404,7 +404,8 @@ free_tsk:
 }
 
 #ifdef CONFIG_MMU
-static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
+static __latent_entropy int dup_mmap(struct mm_struct *mm,
+                                       struct mm_struct *oldmm)
 {
        struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
        struct rb_node **rb_link, *rb_parent;
@@ -798,6 +799,29 @@ struct file *get_mm_exe_file(struct mm_struct *mm)
 }
 EXPORT_SYMBOL(get_mm_exe_file);
 
+/**
+ * get_task_exe_file - acquire a reference to the task's executable file
+ *
+ * Returns %NULL if task's mm (if any) has no associated executable file or
+ * this is a kernel thread with borrowed mm (see the comment above get_task_mm).
+ * User must release file via fput().
+ */
+struct file *get_task_exe_file(struct task_struct *task)
+{
+       struct file *exe_file = NULL;
+       struct mm_struct *mm;
+
+       task_lock(task);
+       mm = task->mm;
+       if (mm) {
+               if (!(task->flags & PF_KTHREAD))
+                       exe_file = get_mm_exe_file(mm);
+       }
+       task_unlock(task);
+       return exe_file;
+}
+EXPORT_SYMBOL(get_task_exe_file);
+
 /**
  * get_task_mm - acquire a reference to the task's mm
  *
@@ -913,14 +937,12 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
        deactivate_mm(tsk, mm);
 
        /*
-        * If we're exiting normally, clear a user-space tid field if
-        * requested.  We leave this alone when dying by signal, to leave
-        * the value intact in a core dump, and to save the unnecessary
-        * trouble, say, a killed vfork parent shouldn't touch this mm.
-        * Userland only wants this done for a sys_exit.
+        * Signal userspace if we're not exiting with a core dump
+        * because we want to leave the value intact for debugging
+        * purposes.
         */
        if (tsk->clear_child_tid) {
-               if (!(tsk->flags & PF_SIGNALED) &&
+               if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) &&
                    atomic_read(&mm->mm_users) > 1) {
                        /*
                         * We don't check the error code - if userspace has
@@ -1275,7 +1297,8 @@ init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
  * parts of the process environment (as per the clone
  * flags). The actual kick-off is left to the caller.
  */
-static struct task_struct *copy_process(unsigned long clone_flags,
+static __latent_entropy struct task_struct *copy_process(
+                                       unsigned long clone_flags,
                                        unsigned long stack_start,
                                        unsigned long stack_size,
                                        int __user *child_tidptr,
@@ -1404,7 +1427,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        p->real_start_time = ktime_get_boot_ns();
        p->io_context = NULL;
        p->audit_context = NULL;
-       threadgroup_change_begin(current);
        cgroup_fork(p);
 #ifdef CONFIG_NUMA
        p->mempolicy = mpol_dup(p->mempolicy);
@@ -1556,6 +1578,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
        INIT_LIST_HEAD(&p->thread_group);
        p->task_works = NULL;
 
+       threadgroup_change_begin(current);
        /*
         * Ensure that the cgroup subsystem policies allow the new process to be
         * forked. It should be noted the the new process's css_set can be changed
@@ -1656,6 +1679,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 bad_fork_cancel_cgroup:
        cgroup_cancel_fork(p);
 bad_fork_free_pid:
+       threadgroup_change_end(current);
        if (pid != &init_struct_pid)
                free_pid(pid);
 bad_fork_cleanup_thread:
@@ -1688,7 +1712,6 @@ bad_fork_cleanup_policy:
        mpol_put(p->mempolicy);
 bad_fork_cleanup_threadgroup_lock:
 #endif
-       threadgroup_change_end(current);
        delayacct_tsk_free(p);
 bad_fork_cleanup_count:
        atomic_dec(&p->cred->user->processes);
@@ -1759,6 +1782,7 @@ long _do_fork(unsigned long clone_flags,
 
        p = copy_process(clone_flags, stack_start, stack_size,
                         child_tidptr, NULL, trace, tls, NUMA_NO_NODE);
+       add_latent_entropy();
        /*
         * Do this prior waking up the new thread - the thread pointer
         * might get invalid after that point, if the thread exits quickly.