4 files changed, 62 insertions, 31 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index f89d373a9c6d..438701adce23 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1165,6 +1165,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,
                       u32 val, ktime_t *abs_time, u32 bitset, int clockrt)
 {
         struct task_struct *curr = current;
+        struct restart_block *restart;
         DECLARE_WAITQUEUE(wait, curr);
         struct futex_hash_bucket *hb;
         struct futex_q q;
@@ -1216,11 +1217,13 @@ retry:
 
                 if (!ret)
                         goto retry;
-                return ret;
+                goto out;
         }
         ret = -EWOULDBLOCK;
-        if (uval != val)
-                goto out_unlock_put_key;
+        if (unlikely(uval != val)) {
+                queue_unlock(&q, hb);
+                goto out_put_key;
+        }
 
         /* Only actually queue if *uaddr contained val.  */
         queue_me(&q, hb);
@@ -1284,38 +1287,38 @@ retry:
          */
 
         /* If we were woken (and unqueued), we succeeded, whatever. */
+        ret = 0;
         if (!unqueue_me(&q))
-                return 0;
+                goto out_put_key;
+        ret = -ETIMEDOUT;
         if (rem)
-                return -ETIMEDOUT;
+                goto out_put_key;
 
         /*
          * We expect signal_pending(current), but another thread may
          * have handled it for us already.
          */
+        ret = -ERESTARTSYS;
         if (!abs_time)
-                return -ERESTARTSYS;
-        else {
-                struct restart_block *restart;
-                restart = &current_thread_info()->restart_block;
-                restart->fn = futex_wait_restart;
-                restart->futex.uaddr = (u32 *)uaddr;
-                restart->futex.val = val;
-                restart->futex.time = abs_time->tv64;
-                restart->futex.bitset = bitset;
-                restart->futex.flags = 0;
-
-                if (fshared)
-                        restart->futex.flags |= FLAGS_SHARED;
-                if (clockrt)
-                        restart->futex.flags |= FLAGS_CLOCKRT;
-                return -ERESTART_RESTARTBLOCK;
-        }
+                goto out_put_key;
 
-out_unlock_put_key:
-        queue_unlock(&q, hb);
-        put_futex_key(fshared, &q.key);
+        restart = &current_thread_info()->restart_block;
+        restart->fn = futex_wait_restart;
+        restart->futex.uaddr = (u32 *)uaddr;
+        restart->futex.val = val;
+        restart->futex.time = abs_time->tv64;
+        restart->futex.bitset = bitset;
+        restart->futex.flags = 0;
+
+        if (fshared)
+                restart->futex.flags |= FLAGS_SHARED;
+        if (clockrt)
+                restart->futex.flags |= FLAGS_CLOCKRT;
 
+        ret = -ERESTART_RESTARTBLOCK;
+
+out_put_key:
+        put_futex_key(fshared, &q.key);
 out:
         return ret;
 }
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index e2a4ff6fc3a6..58a93fbd68aa 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -302,4 +302,27 @@ config FTRACE_STARTUP_TEST
           functioning properly. It will do tests on all the configured
           tracers of ftrace.
 
+config MMIOTRACE
+        bool "Memory mapped IO tracing"
+        depends on HAVE_MMIOTRACE_SUPPORT && DEBUG_KERNEL && PCI
+        select TRACING
+        help
+          Mmiotrace traces Memory Mapped I/O access and is meant for
+          debugging and reverse engineering. It is called from the ioremap
+          implementation and works via page faults. Tracing is disabled by
+          default and can be enabled at run-time.
+
+          See Documentation/tracers/mmiotrace.txt.
+          If you are not helping to develop drivers, say N.
+
+config MMIOTRACE_TEST
+        tristate "Test module for mmiotrace"
+        depends on MMIOTRACE && m
+        help
+          This is a dumb module for testing mmiotrace. It is very dangerous
+          as it will write garbage to IO memory starting at a given address.
+          However, it should be safe to use on e.g. unused portion of VRAM.
+
+          Say N, unless you absolutely know what you are doing.
+
 endmenu
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index fffcb069f1dc..80e503ef6136 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/mmiotrace.h>
 #include <linux/pci.h>
+#include <asm/atomic.h>
 
 #include "trace.h"
 
@@ -19,6 +20,7 @@ struct header_iter {
 static struct trace_array *mmio_trace_array;
 static bool overrun_detected;
 static unsigned long prev_overruns;
+static atomic_t dropped_count;
 
 static void mmio_reset_data(struct trace_array *tr)
 {
@@ -121,11 +123,11 @@ static void mmio_close(struct trace_iterator *iter)
 
 static unsigned long count_overruns(struct trace_iterator *iter)
 {
-        unsigned long cnt = 0;
+        unsigned long cnt = atomic_xchg(&dropped_count, 0);
         unsigned long over = ring_buffer_overruns(iter->tr->buffer);
 
         if (over > prev_overruns)
-                cnt = over - prev_overruns;
+                cnt += over - prev_overruns;
         prev_overruns = over;
         return cnt;
 }
@@ -310,8 +312,10 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
 
         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
                                            &irq_flags);
-        if (!event)
+        if (!event) {
+                atomic_inc(&dropped_count);
                 return;
+        }
         entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
         entry->ent.type                 = TRACE_MMIO_RW;
@@ -338,8 +342,10 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
 
         event   = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
                                            &irq_flags);
-        if (!event)
+        if (!event) {
+                atomic_inc(&dropped_count);
                 return;
+        }
         entry   = ring_buffer_event_data(event);
         tracing_generic_entry_update(&entry->ent, 0, preempt_count());
         entry->ent.type                 = TRACE_MMIO_MAP;
diff --git a/kernel/user.c b/kernel/user.c
index 477b6660f447..3551ac742395 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -72,6 +72,7 @@ static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
 static void uid_hash_remove(struct user_struct *up)
 {
         hlist_del_init(&up->uidhash_node);
+        put_user_ns(up->user_ns);
 }
 
 static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
@@ -334,7 +335,6 @@ static void free_user(struct user_struct *up, unsigned long flags)
         atomic_inc(&up->__count);
         spin_unlock_irqrestore(&uidhash_lock, flags);
 
-        put_user_ns(up->user_ns);
         INIT_WORK(&up->work, remove_user_sysfs_dir);
         schedule_work(&up->work);
 }
@@ -357,7 +357,6 @@ static void free_user(struct user_struct *up, unsigned long flags)
         sched_destroy_user(up);
         key_put(up->uid_keyring);
         key_put(up->session_keyring);
-        put_user_ns(up->user_ns);
         kmem_cache_free(uid_cachep, up);
 }