8 files changed, 58 insertions, 97 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 17670573dda8..ba2b0c87e65b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1281,6 +1281,7 @@ config RCU_TORTURE_TEST_SLOW_INIT_DELAY
         int "How much to slow down RCU grace-period initialization"
         range 0 5
         default 3
+        depends on RCU_TORTURE_TEST_SLOW_INIT
         help
           This option specifies the number of jiffies to wait between
           each rcu_node structure initialization.
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 4fecaedc80a2..777eda7d1ab4 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -10,8 +10,11 @@ config KASAN
         help
           Enables kernel address sanitizer - runtime memory debugger,
           designed to find out-of-bounds accesses and use-after-free bugs.
-          This is strictly debugging feature. It consumes about 1/8
-          of available memory and brings about ~x3 performance slowdown.
+          This is strictly a debugging feature and it requires a gcc version
+          of 4.9.2 or later. Detection of out of bounds accesses to stack or
+          global variables requires gcc 5.0 or later.
+          This feature consumes about 1/8 of available memory and brings about
+          ~x3 performance slowdown.
           For better error detection enable CONFIG_STACKTRACE,
           and add slub_debug=U to boot cmdline.
 
@@ -40,6 +43,7 @@ config KASAN_INLINE
           memory accesses. This is faster than outline (in some workloads
           it gives about x2 boost over outline instrumentation), but
           make kernel's .text size much bigger.
+          This requires a gcc version of 5.0 or later.
 
 endchoice
 
diff --git a/lib/cpumask.c b/lib/cpumask.c
index 830dd5dec40f..5f627084f2e9 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -139,64 +139,42 @@ void __init free_bootmem_cpumask_var(cpumask_var_t mask)
 #endif
 
 /**
- * cpumask_set_cpu_local_first - set i'th cpu with local numa cpu's first
- *
+ * cpumask_local_spread - select the i'th cpu with local numa cpu's first
  * @i: index number
- * @numa_node: local numa_node
- * @dstp: cpumask with the relevant cpu bit set according to the policy
+ * @node: local numa_node
  *
- * This function sets the cpumask according to a numa aware policy.
- * cpumask could be used as an affinity hint for the IRQ related to a
- * queue. When the policy is to spread queues across cores - local cores
- * first.
+ * This function selects an online CPU according to a numa aware policy;
+ * local cpus are returned first, followed by non-local ones, then it
+ * wraps around.
  *
- * Returns 0 on success, -ENOMEM for no memory, and -EAGAIN when failed to set
- * the cpu bit and need to re-call the function.
+ * It's not very efficient, but useful for setup.
  */
-int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp)
+unsigned int cpumask_local_spread(unsigned int i, int node)
 {
-        cpumask_var_t mask;
         int cpu;
-        int ret = 0;
-
-        if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
-                return -ENOMEM;
 
+        /* Wrap: we always want a cpu. */
         i %= num_online_cpus();
 
-        if (numa_node == -1 || !cpumask_of_node(numa_node)) {
-                /* Use all online cpu's for non numa aware system */
-                cpumask_copy(mask, cpu_online_mask);
+        if (node == -1) {
+                for_each_cpu(cpu, cpu_online_mask)
+                        if (i-- == 0)
+                                return cpu;
         } else {
-                int n;
-
-                cpumask_and(mask,
-                            cpumask_of_node(numa_node), cpu_online_mask);
-
-                n = cpumask_weight(mask);
-                if (i >= n) {
-                        i -= n;
-
-                        /* If index > number of local cpu's, mask out local
-                         * cpu's
-                         */
-                        cpumask_andnot(mask, cpu_online_mask, mask);
+                /* NUMA first. */
+                for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask)
+                        if (i-- == 0)
+                                return cpu;
+
+                for_each_cpu(cpu, cpu_online_mask) {
+                        /* Skip NUMA nodes, done above. */
+                        if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
+                                continue;
+
+                        if (i-- == 0)
+                                return cpu;
                 }
         }
-
-        for_each_cpu(cpu, mask) {
-                if (--i < 0)
-                        goto out;
-        }
-
-        ret = -EAGAIN;
-
-out:
-        free_cpumask_var(mask);
-
-        if (!ret)
-                cpumask_set_cpu(cpu, dstp);
-
-        return ret;
+        BUG();
 }
-EXPORT_SYMBOL(cpumask_set_cpu_local_first);
+EXPORT_SYMBOL(cpumask_local_spread);
diff --git a/lib/find_last_bit.c b/lib/find_last_bit.c
deleted file mode 100644
index 3e3be40c6a6e..000000000000
--- a/lib/find_last_bit.c
+++ /dev/null
@@ -1,41 +0,0 @@
-/* find_last_bit.c: fallback find next bit implementation
- *
- * Copyright (C) 2008 IBM Corporation
- * Written by Rusty Russell <rusty@rustcorp.com.au>
- * (Inspired by David Howell's find_next_bit implementation)
- *
- * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease
- * size and improve performance, 2015.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#include <linux/bitops.h>
-#include <linux/bitmap.h>
-#include <linux/export.h>
-#include <linux/kernel.h>
-
-#ifndef find_last_bit
-
-unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
-{
-        if (size) {
-                unsigned long val = BITMAP_LAST_WORD_MASK(size);
-                unsigned long idx = (size-1) / BITS_PER_LONG;
-
-                do {
-                        val &= addr[idx];
-                        if (val)
-                                return idx * BITS_PER_LONG + __fls(val);
-
-                        val = ~0ul;
-                } while (idx--);
-        }
-        return size;
-}
-EXPORT_SYMBOL(find_last_bit);
-
-#endif
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 48144cdae819..f051d69f0910 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -197,13 +197,13 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
  * Compare counter against given value.
  * Return 1 if greater, 0 if equal and -1 if less
  */
-int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
+int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch)
 {
         s64     count;
 
         count = percpu_counter_read(fbc);
         /* Check to see if rough count will be sufficient for comparison */
-        if (abs(count - rhs) > (percpu_counter_batch*num_online_cpus())) {
+        if (abs(count - rhs) > (batch * num_online_cpus())) {
                 if (count > rhs)
                         return 1;
                 else
@@ -218,7 +218,7 @@ int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
         else
                 return 0;
 }
-EXPORT_SYMBOL(percpu_counter_compare);
+EXPORT_SYMBOL(__percpu_counter_compare);
 
 static int __init percpu_counter_startup(void)
 {
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index b28df4019ade..4396434e4715 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -14,6 +14,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/atomic.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/log2.h>
@@ -446,6 +447,10 @@ int rhashtable_insert_slow(struct rhashtable *ht, const void *key,
         if (key && rhashtable_lookup_fast(ht, key, ht->p))
                 goto exit;
 
+        err = -E2BIG;
+        if (unlikely(rht_grow_above_max(ht, tbl)))
+                goto exit;
+
         err = -EAGAIN;
         if (rhashtable_check_elasticity(ht, tbl, hash) ||
             rht_grow_above_100(ht, tbl))
@@ -738,6 +743,12 @@ int rhashtable_init(struct rhashtable *ht,
         if (params->max_size)
                 ht->p.max_size = rounddown_pow_of_two(params->max_size);
 
+        if (params->insecure_max_entries)
+                ht->p.insecure_max_entries =
+                        rounddown_pow_of_two(params->insecure_max_entries);
+        else
+                ht->p.insecure_max_entries = ht->p.max_size * 2;
+
         ht->p.min_size = max(ht->p.min_size, HASH_MIN_SIZE);
 
         /* The maximum (not average) chain length grows with the
diff --git a/lib/string.c b/lib/string.c
index a5792019193c..bb3d4b6993c4 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -607,7 +607,7 @@ EXPORT_SYMBOL(memset);
 void memzero_explicit(void *s, size_t count)
 {
         memset(s, 0, count);
-        barrier();
+        barrier_data(s);
 }
 EXPORT_SYMBOL(memzero_explicit);
 
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
index a28df5206d95..fe9a32591c24 100644
--- a/lib/strnlen_user.c
+++ b/lib/strnlen_user.c
@@ -57,7 +57,8 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
                         return res + find_zero(data) + 1 - align;
                 }
                 res += sizeof(unsigned long);
-                if (unlikely(max < sizeof(unsigned long)))
+                /* We already handled 'unsigned long' bytes. Did we do it all ? */
+                if (unlikely(max <= sizeof(unsigned long)))
                         break;
                 max -= sizeof(unsigned long);
                 if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
@@ -89,8 +90,15 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
  * Get the size of a NUL-terminated string in user space.
  *
  * Returns the size of the string INCLUDING the terminating NUL.
- * If the string is too long, returns 'count+1'.
+ * If the string is too long, returns a number larger than @count. User
+ * has to check the return value against "> count".
  * On exception (or invalid count), returns 0.
+ *
+ * NOTE! You should basically never use this function. There is
+ * almost never any valid case for using the length of a user space
+ * string, since the string can be changed at any time by other
+ * threads. Use "strncpy_from_user()" instead to get a stable copy
+ * of the string.
  */
 long strnlen_user(const char __user *str, long count)
 {