---

yaml
---
r: 166513
b: refs/heads/master
c: 6ea529a
h: refs/heads/master
i:
  166511: c98c0e8
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a70c691376c7c7f94af41395848066f59501fffd
+refs/heads/master: 6ea529a2037ce662fc6bfa572b46d47407d08805

trunk/mm/percpu.c

@@ -1786,7 +1786,7 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
 	void *base = (void *)ULONG_MAX;
 	void **areas = NULL;
 	struct pcpu_alloc_info *ai;
-	size_t size_sum, areas_size;
+	size_t size_sum, areas_size, max_distance;
 	int group, i, rc;
 
 	ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
@@ -1836,8 +1836,24 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
 	}
 
 	/* base address is now known, determine group base offsets */
-	for (group = 0; group < ai->nr_groups; group++)
+	max_distance = 0;
+	for (group = 0; group < ai->nr_groups; group++) {
 		ai->groups[group].base_offset = areas[group] - base;
+		max_distance = max(max_distance, ai->groups[group].base_offset);
+	}
+	max_distance += ai->unit_size;
+
+	/* warn if maximum distance is further than 75% of vmalloc space */
+	if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) {
+		pr_warning("PERCPU: max_distance=0x%lx too large for vmalloc "
+			   "space 0x%lx\n",
+			   max_distance, VMALLOC_END - VMALLOC_START);
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+		/* and fail if we have fallback */
+		rc = -EINVAL;
+		goto out_free;
+#endif
+	}
 
 	pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
 		PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,