8 files changed, 51 insertions, 14 deletions

diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index c438f545a321..be775f7e81e0 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -255,7 +255,14 @@ extern void kdb_ps1(const struct task_struct *p);
 extern void kdb_print_nameval(const char *name, unsigned long val);
 extern void kdb_send_sig_info(struct task_struct *p, struct siginfo *info);
 extern void kdb_meminfo_proc_show(void);
+#ifdef CONFIG_KALLSYMS
 extern const char *kdb_walk_kallsyms(loff_t *pos);
+#else /* ! CONFIG_KALLSYMS */
+static inline const char *kdb_walk_kallsyms(loff_t *pos)
+{
+        return NULL;
+}
+#endif /* ! CONFIG_KALLSYMS */
 extern char *kdb_getstr(char *, size_t, char *);
 
 /* Defines for kdb_symbol_print */
diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c
index 45344d5c53dd..6b2485dcb050 100644
--- a/kernel/debug/kdb/kdb_support.c
+++ b/kernel/debug/kdb/kdb_support.c
@@ -82,8 +82,8 @@ static char *kdb_name_table[100];	/* arbitrary size */
 int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
 {
         int ret = 0;
-        unsigned long symbolsize;
-        unsigned long offset;
+        unsigned long symbolsize = 0;
+        unsigned long offset = 0;
 #define knt1_size 128           /* must be >= kallsyms table size */
         char *knt1 = NULL;
 
diff --git a/kernel/exit.c b/kernel/exit.c
index 671ed56e0a49..03120229db28 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1386,8 +1386,7 @@ static int wait_task_stopped(struct wait_opts *wo,
         if (!unlikely(wo->wo_flags & WNOWAIT))
                 *p_code = 0;
 
-        /* don't need the RCU readlock here as we're holding a spinlock */
-        uid = __task_cred(p)->uid;
+        uid = task_uid(p);
 unlock_sig:
         spin_unlock_irq(&p->sighand->siglock);
         if (!exit_code)
@@ -1460,7 +1459,7 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
         }
         if (!unlikely(wo->wo_flags & WNOWAIT))
                 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
-        uid = __task_cred(p)->uid;
+        uid = task_uid(p);
         spin_unlock_irq(&p->sighand->siglock);
 
         pid = task_pid_vnr(p);
diff --git a/kernel/fork.c b/kernel/fork.c
index 98b450876f93..b7e9d60a675d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -300,7 +300,7 @@ out:
 #ifdef CONFIG_MMU
 static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 {
-        struct vm_area_struct *mpnt, *tmp, **pprev;
+        struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
         struct rb_node **rb_link, *rb_parent;
         int retval;
         unsigned long charge;
@@ -328,6 +328,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
         if (retval)
                 goto out;
 
+        prev = NULL;
         for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
                 struct file *file;
 
@@ -359,7 +360,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
                         goto fail_nomem_anon_vma_fork;
                 tmp->vm_flags &= ~VM_LOCKED;
                 tmp->vm_mm = mm;
-                tmp->vm_next = NULL;
+                tmp->vm_next = tmp->vm_prev = NULL;
                 file = tmp->vm_file;
                 if (file) {
                         struct inode *inode = file->f_path.dentry->d_inode;
@@ -392,6 +393,8 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
                  */
                 *pprev = tmp;
                 pprev = &tmp->vm_next;
+                tmp->vm_prev = prev;
+                prev = tmp;
 
                 __vma_link_rb(mm, tmp, rb_link, rb_parent);
                 rb_link = &tmp->vm_rb.rb_right;
@@ -752,13 +755,13 @@ static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
         struct fs_struct *fs = current->fs;
         if (clone_flags & CLONE_FS) {
                 /* tsk->fs is already what we want */
-                write_lock(&fs->lock);
+                spin_lock(&fs->lock);
                 if (fs->in_exec) {
-                        write_unlock(&fs->lock);
+                        spin_unlock(&fs->lock);
                         return -EAGAIN;
                 }
                 fs->users++;
-                write_unlock(&fs->lock);
+                spin_unlock(&fs->lock);
                 return 0;
         }
         tsk->fs = copy_fs_struct(fs);
@@ -1676,13 +1679,13 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
 
                 if (new_fs) {
                         fs = current->fs;
-                        write_lock(&fs->lock);
+                        spin_lock(&fs->lock);
                         current->fs = new_fs;
                         if (--fs->users)
                                 new_fs = NULL;
                         else
                                 new_fs = fs;
-                        write_unlock(&fs->lock);
+                        spin_unlock(&fs->lock);
                 }
 
                 if (new_mm) {
diff --git a/kernel/kfifo.c b/kernel/kfifo.c
index 4502604ecadf..6b5580c57644 100644
--- a/kernel/kfifo.c
+++ b/kernel/kfifo.c
@@ -503,6 +503,15 @@ unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,
 }
 EXPORT_SYMBOL(__kfifo_out_r);
 
+void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize)
+{
+        unsigned int n;
+
+        n = __kfifo_peek_n(fifo, recsize);
+        fifo->out += n + recsize;
+}
+EXPORT_SYMBOL(__kfifo_skip_r);
+
 int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from,
         unsigned long len, unsigned int *copied, size_t recsize)
 {
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 6e9b19667a8d..9cd0591c96a2 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -153,7 +153,9 @@ static int ____call_usermodehelper(void *data)
                         goto fail;
         }
 
-        retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp);
+        retval = kernel_execve(sub_info->path,
+                               (const char *const *)sub_info->argv,
+                               (const char *const *)sub_info->envp);
 
         /* Exec failed? */
 fail:
diff --git a/kernel/sched.c b/kernel/sched.c
index 41541d79e3c8..09b574e7f4df 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3865,8 +3865,16 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
                 /*
                  * Owner changed, break to re-assess state.
                  */
-                if (lock->owner != owner)
+                if (lock->owner != owner) {
+                        /*
+                         * If the lock has switched to a different owner,
+                         * we likely have heavy contention. Return 0 to quit
+                         * optimistic spinning and not contend further:
+                         */
+                        if (lock->owner)
+                                return 0;
                         break;
+                }
 
                 /*
                  * Is that owner really running on that cpu?
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 2994a0e3a61c..8bd600c020e5 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -35,6 +35,9 @@
 #include <linux/lockdep.h>
 #include <linux/idr.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/workqueue.h>
+
 #include "workqueue_sched.h"
 
 enum {
@@ -1790,7 +1793,13 @@ static void process_one_work(struct worker *worker, struct work_struct *work)
         work_clear_pending(work);
         lock_map_acquire(&cwq->wq->lockdep_map);
         lock_map_acquire(&lockdep_map);
+        trace_workqueue_execute_start(work);
         f(work);
+        /*
+         * While we must be careful to not use "work" after this, the trace
+         * point will only record its address.
+         */
+        trace_workqueue_execute_end(work);
         lock_map_release(&lockdep_map);
         lock_map_release(&cwq->wq->lockdep_map);