sched/membarrier: Return -ENOMEM to userspace on memory allocation failure

[linux.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 2852d0e76ea3b905693a454f36e21524c14a8b54..d6e552552e526d5ec9bc078170f0fcabc8b12abf 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -768,6 +768,7 @@ static void set_max_threads(unsigned int max_threads_suggested)
 int arch_task_struct_size __read_mostly;
 #endif
 
+#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
 static void task_struct_whitelist(unsigned long *offset, unsigned long *size)
 {
        /* Fetch thread_struct whitelist for the architecture. */
@@ -782,6 +783,7 @@ static void task_struct_whitelist(unsigned long *offset, unsigned long *size)
        else
                *offset += offsetof(struct task_struct, thread);
 }
+#endif /* CONFIG_ARCH_TASK_STRUCT_ALLOCATOR */
 
 void __init fork_init(void)
 {
@@ -901,10 +903,12 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
                tsk->cpus_ptr = &tsk->cpus_mask;
 
        /*
-        * One for us, one for whoever does the "release_task()" (usually
-        * parent)
+        * One for the user space visible state that goes away when reaped.
+        * One for the scheduler.
         */
-       refcount_set(&tsk->usage, 2);
+       refcount_set(&tsk->rcu_users, 2);
+       /* One for the rcu users */
+       refcount_set(&tsk->usage, 1);
 #ifdef CONFIG_BLK_DEV_IO_TRACE
        tsk->btrace_seq = 0;
 #endif
@@ -1690,6 +1694,14 @@ static inline void rcu_copy_process(struct task_struct *p)
 #endif /* #ifdef CONFIG_TASKS_RCU */
 }
 
+struct pid *pidfd_pid(const struct file *file)
+{
+       if (file->f_op == &pidfd_fops)
+               return file->private_data;
+
+       return ERR_PTR(-EBADF);
+}
+
 static int pidfd_release(struct inode *inode, struct file *file)
 {
        struct pid *pid = file->private_data;
@@ -2338,6 +2350,8 @@ struct mm_struct *copy_init_mm(void)
  *
  * It copies the process, and if successful kick-starts
  * it and waits for it to finish using the VM if required.
+ *
+ * args->exit_signal is expected to be checked for sanity by the caller.
  */
 long _do_fork(struct kernel_clone_args *args)
 {
@@ -2562,6 +2576,14 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
        if (copy_from_user(&args, uargs, size))
                return -EFAULT;
 
+       /*
+        * Verify that higher 32bits of exit_signal are unset and that
+        * it is a valid signal
+        */
+       if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) ||
+                    !valid_signal(args.exit_signal)))
+               return -EINVAL;
+
        *kargs = (struct kernel_clone_args){
                .flags          = args.flags,
                .pidfd          = u64_to_user_ptr(args.pidfd),