1 files changed, 26 insertions, 11 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index c43da8c024d1..83617ca3ba52 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1578,6 +1578,7 @@ static void pcpu_dump_alloc_info(const char *lvl,
 int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
                                   void *base_addr)
 {
+        static char cpus_buf[4096] __initdata;
         static int smap[2], dmap[2];
         size_t dyn_size = ai->dyn_size;
         size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
@@ -1589,17 +1590,26 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
         int *unit_map;
         int group, unit, i;
 
+        cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask);
+
+#define PCPU_SETUP_BUG_ON(cond) do {                                    \
+        if (unlikely(cond)) {                                           \
+                pr_emerg("PERCPU: failed to initialize, %s", #cond);    \
+                pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf);   \
+                pcpu_dump_alloc_info(KERN_EMERG, ai);                   \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
         /* sanity checks */
         BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
                      ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
-        BUG_ON(ai->nr_groups <= 0);
-        BUG_ON(!ai->static_size);
-        BUG_ON(!base_addr);
-        BUG_ON(ai->unit_size < size_sum);
-        BUG_ON(ai->unit_size & ~PAGE_MASK);
-        BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
-
-        pcpu_dump_alloc_info(KERN_DEBUG, ai);
+        PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
+        PCPU_SETUP_BUG_ON(!ai->static_size);
+        PCPU_SETUP_BUG_ON(!base_addr);
+        PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
+        PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
+        PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
 
         /* process group information and build config tables accordingly */
         group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
@@ -1622,8 +1632,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
                         if (cpu == NR_CPUS)
                                 continue;
 
-                        BUG_ON(cpu > nr_cpu_ids || !cpu_possible(cpu));
-                        BUG_ON(unit_map[cpu] != UINT_MAX);
+                        PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
+                        PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
+                        PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
 
                         unit_map[cpu] = unit + i;
                         unit_off[cpu] = gi->base_offset + i * ai->unit_size;
@@ -1636,7 +1647,11 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
         pcpu_nr_units = unit;
 
         for_each_possible_cpu(cpu)
-                BUG_ON(unit_map[cpu] == UINT_MAX);
+                PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
+
+        /* we're done parsing the input, undefine BUG macro and dump config */
+#undef PCPU_SETUP_BUG_ON
+        pcpu_dump_alloc_info(KERN_INFO, ai);
 
         pcpu_nr_groups = ai->nr_groups;
         pcpu_group_offsets = group_offsets;