Merge tag 'v5.1' into next

Sync up with mainline to bring in the latest APIs.

1 files changed, 29 insertions, 24 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index e2a5156bc9c3..9dcd18aa210b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -77,7 +77,6 @@
 #include <linux/blkdev.h>
 #include <linux/fs_struct.h>
 #include <linux/magic.h>
-#include <linux/sched/mm.h>
 #include <linux/perf_event.h>
 #include <linux/posix-timers.h>
 #include <linux/user-return-notifier.h>
@@ -164,10 +163,6 @@ static inline void free_task_struct(struct task_struct *tsk)
 }
 #endif
 
-void __weak arch_release_thread_stack(unsigned long *stack)
-{
-}
-
 #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
 
 /*
@@ -221,6 +216,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
 		memset(s->addr, 0, THREAD_SIZE);
 
 		tsk->stack_vm_area = s;
+		tsk->stack = s->addr;
 		return s->addr;
 	}
 
@@ -422,7 +418,6 @@ static void release_task_stack(struct task_struct *tsk)
 		return;  /* Better to leak the stack than to free prematurely */
 
 	account_kernel_stack(tsk, -1);
-	arch_release_thread_stack(tsk->stack);
 	free_thread_stack(tsk);
 	tsk->stack = NULL;
 #ifdef CONFIG_VMAP_STACK
@@ -433,7 +428,7 @@ static void release_task_stack(struct task_struct *tsk)
 #ifdef CONFIG_THREAD_INFO_IN_TASK
 void put_task_stack(struct task_struct *tsk)
 {
-	if (atomic_dec_and_test(&tsk->stack_refcount))
+	if (refcount_dec_and_test(&tsk->stack_refcount))
 		release_task_stack(tsk);
 }
 #endif
@@ -451,7 +446,7 @@ void free_task(struct task_struct *tsk)
 	 * If the task had a separate stack allocation, it should be gone
 	 * by now.
 	 */
-	WARN_ON_ONCE(atomic_read(&tsk->stack_refcount) != 0);
+	WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
 #endif
 	rt_mutex_debug_task_free(tsk);
 	ftrace_graph_exit_task(tsk);
@@ -714,14 +709,14 @@ static inline void free_signal_struct(struct signal_struct *sig)
 
 static inline void put_signal_struct(struct signal_struct *sig)
 {
-	if (atomic_dec_and_test(&sig->sigcnt))
+	if (refcount_dec_and_test(&sig->sigcnt))
 		free_signal_struct(sig);
 }
 
 void __put_task_struct(struct task_struct *tsk)
 {
 	WARN_ON(!tsk->exit_state);
-	WARN_ON(atomic_read(&tsk->usage));
+	WARN_ON(refcount_read(&tsk->usage));
 	WARN_ON(tsk == current);
 
 	cgroup_free(tsk);
@@ -744,15 +739,16 @@ void __init __weak arch_task_cache_init(void) { }
 static void set_max_threads(unsigned int max_threads_suggested)
 {
 	u64 threads;
+	unsigned long nr_pages = totalram_pages();
 
 	/*
 	 * The number of threads shall be limited such that the thread
 	 * structures may only consume a small part of the available memory.
 	 */
-	if (fls64(totalram_pages) + fls64(PAGE_SIZE) > 64)
+	if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64)
 		threads = MAX_THREADS;
 	else
-		threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE,
+		threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE,
 				    (u64) THREAD_SIZE * 8UL);
 
 	if (threads > max_threads_suggested)
@@ -840,7 +836,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 {
 	struct task_struct *tsk;
 	unsigned long *stack;
-	struct vm_struct *stack_vm_area;
+	struct vm_struct *stack_vm_area __maybe_unused;
 	int err;
 
 	if (node == NUMA_NO_NODE)
@@ -870,7 +866,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	tsk->stack_vm_area = stack_vm_area;
 #endif
 #ifdef CONFIG_THREAD_INFO_IN_TASK
-	atomic_set(&tsk->stack_refcount, 1);
+	refcount_set(&tsk->stack_refcount, 1);
 #endif
 
 	if (err)
@@ -899,7 +895,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	 * One for us, one for whoever does the "release_task()" (usually
 	 * parent)
 	 */
-	atomic_set(&tsk->usage, 2);
+	refcount_set(&tsk->usage, 2);
 #ifdef CONFIG_BLK_DEV_IO_TRACE
 	tsk->btrace_seq = 0;
 #endif
@@ -984,7 +980,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
 	mm_pgtables_bytes_init(mm);
 	mm->map_count = 0;
 	mm->locked_vm = 0;
-	mm->pinned_vm = 0;
+	atomic64_set(&mm->pinned_vm, 0);
 	memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
 	spin_lock_init(&mm->page_table_lock);
 	spin_lock_init(&mm->arg_lock);
@@ -1466,7 +1462,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
 	struct sighand_struct *sig;
 
 	if (clone_flags & CLONE_SIGHAND) {
-		atomic_inc(&current->sighand->count);
+		refcount_inc(&current->sighand->count);
 		return 0;
 	}
 	sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
@@ -1474,7 +1470,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
 	if (!sig)
 		return -ENOMEM;
 
-	atomic_set(&sig->count, 1);
+	refcount_set(&sig->count, 1);
 	spin_lock_irq(&current->sighand->siglock);
 	memcpy(sig->action, current->sighand->action, sizeof(sig->action));
 	spin_unlock_irq(&current->sighand->siglock);
@@ -1483,7 +1479,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
 
 void __cleanup_sighand(struct sighand_struct *sighand)
 {
-	if (atomic_dec_and_test(&sighand->count)) {
+	if (refcount_dec_and_test(&sighand->count)) {
 		signalfd_cleanup(sighand);
 		/*
 		 * sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
@@ -1530,7 +1526,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
 
 	sig->nr_threads = 1;
 	atomic_set(&sig->live, 1);
-	atomic_set(&sig->sigcnt, 1);
+	refcount_set(&sig->sigcnt, 1);
 
 	/* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
 	sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
@@ -1837,8 +1833,6 @@ static __latent_entropy struct task_struct *copy_process(
 
 	posix_cpu_timers_init(p);
 
-	p->start_time = ktime_get_ns();
-	p->real_start_time = ktime_get_boot_ns();
 	p->io_context = NULL;
 	audit_set_context(p, NULL);
 	cgroup_fork(p);
@@ -2005,6 +1999,17 @@ static __latent_entropy struct task_struct *copy_process(
 		goto bad_fork_free_pid;
 
 	/*
+	 * From this point on we must avoid any synchronous user-space
+	 * communication until we take the tasklist-lock. In particular, we do
+	 * not want user-space to be able to predict the process start-time by
+	 * stalling fork(2) after we recorded the start_time but before it is
+	 * visible to the system.
+	 */
+
+	p->start_time = ktime_get_ns();
+	p->real_start_time = ktime_get_boot_ns();
+
+	/*
 	 * Make it visible to the rest of the system, but dont wake it up yet.
 	 * Need tasklist lock for parent etc handling!
 	 */
@@ -2076,7 +2081,7 @@ static __latent_entropy struct task_struct *copy_process(
 		} else {
 			current->signal->nr_threads++;
 			atomic_inc(&current->signal->live);
-			atomic_inc(&current->signal->sigcnt);
+			refcount_inc(&current->signal->sigcnt);
 			task_join_group_stop(p);
 			list_add_tail_rcu(&p->thread_group,
 					  &p->group_leader->thread_group);
@@ -2433,7 +2438,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
 			return -EINVAL;
 	}
 	if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
-		if (atomic_read(&current->sighand->count) > 1)
+		if (refcount_read(&current->sighand->count) > 1)
 			return -EINVAL;
 	}
 	if (unshare_flags & CLONE_VM) {