1 files changed, 35 insertions, 25 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 952741f6d0f9..e99aff33ff14 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -426,22 +426,10 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
 	 */
 	rcu_read_lock();
 	ucounts = task_ucounts(t);
-	sigpending = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1);
-	switch (sigpending) {
-	case 1:
-		if (likely(get_ucounts(ucounts)))
-			break;
-		fallthrough;
-	case LONG_MAX:
-		/*
-		 * we need to decrease the ucount in the userns tree on any
-		 * failure to avoid counts leaking.
-		 */
-		dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1);
-		rcu_read_unlock();
-		return NULL;
-	}
+	sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
 	rcu_read_unlock();
+	if (!sigpending)
+		return NULL;
 
 	if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
 		q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
@@ -450,8 +438,7 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
 	}
 
 	if (unlikely(q == NULL)) {
-		if (dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING, 1))
-			put_ucounts(ucounts);
+		dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
 	} else {
 		INIT_LIST_HEAD(&q->list);
 		q->flags = sigqueue_flags;
@@ -464,8 +451,8 @@ static void __sigqueue_free(struct sigqueue *q)
 {
 	if (q->flags & SIGQUEUE_PREALLOC)
 		return;
-	if (q->ucounts && dec_rlimit_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING, 1)) {
-		put_ucounts(q->ucounts);
+	if (q->ucounts) {
+		dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING);
 		q->ucounts = NULL;
 	}
 	kmem_cache_free(sigqueue_cachep, q);
@@ -4151,11 +4138,29 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
 	return 0;
 }
 
+#ifdef CONFIG_DYNAMIC_SIGFRAME
+static inline void sigaltstack_lock(void)
+	__acquires(&current->sighand->siglock)
+{
+	spin_lock_irq(&current->sighand->siglock);
+}
+
+static inline void sigaltstack_unlock(void)
+	__releases(&current->sighand->siglock)
+{
+	spin_unlock_irq(&current->sighand->siglock);
+}
+#else
+static inline void sigaltstack_lock(void) { }
+static inline void sigaltstack_unlock(void) { }
+#endif
+
 static int
 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
 		size_t min_ss_size)
 {
 	struct task_struct *t = current;
+	int ret = 0;
 
 	if (oss) {
 		memset(oss, 0, sizeof(stack_t));
@@ -4179,19 +4184,24 @@ do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
 				ss_mode != 0))
 			return -EINVAL;
 
+		sigaltstack_lock();
 		if (ss_mode == SS_DISABLE) {
 			ss_size = 0;
 			ss_sp = NULL;
 		} else {
 			if (unlikely(ss_size < min_ss_size))
-				return -ENOMEM;
+				ret = -ENOMEM;
+			if (!sigaltstack_size_valid(ss_size))
+				ret = -ENOMEM;
 		}
-
-		t->sas_ss_sp = (unsigned long) ss_sp;
-		t->sas_ss_size = ss_size;
-		t->sas_ss_flags = ss_flags;
+		if (!ret) {
+			t->sas_ss_sp = (unsigned long) ss_sp;
+			t->sas_ss_size = ss_size;
+			t->sas_ss_flags = ss_flags;
+		}
+		sigaltstack_unlock();
 	}
-	return 0;
+	return ret;
 }
 
 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)