Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  ftrace: Revert 8ab2b7efd ftrace: Remove unnecessary disabling of irqs
  kprobes/trace: Fix kprobe selftest for gcc 4.6
  ftrace: Fix possible undefined return code
  oprofile, dcookies: Fix possible circular locking dependency
  oprofile: Fix locking dependency in sync_start()
  oprofile: Free potentially owned tasks in case of errors
  oprofile, x86: Add comments to IBS LVT offset initialization

6 files changed, 39 insertions, 18 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index b961af86bfea..b9338b8cf420 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -390,7 +390,8 @@ static unsigned int reserve_eilvt_offset(int offset, unsigned int new)
 
 /*
  * If mask=1, the LVT entry does not generate interrupts while mask=0
- * enables the vector. See also the BKDGs.
+ * enables the vector. See also the BKDGs. Must be called with
+ * preemption disabled.
  */
 
 int setup_APIC_eilvt(u8 offset, u8 vector, u8 msg_type, u8 mask)
diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index 9fd8a567fe1e..9cbb710dc94b 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -609,16 +609,21 @@ static int setup_ibs_ctl(int ibs_eilvt_off)
         return 0;
 }
 
+/*
+ * This runs only on the current cpu. We try to find an LVT offset and
+ * setup the local APIC. For this we must disable preemption. On
+ * success we initialize all nodes with this offset. This updates then
+ * the offset in the IBS_CTL per-node msr. The per-core APIC setup of
+ * the IBS interrupt vector is called from op_amd_setup_ctrs()/op_-
+ * amd_cpu_shutdown() using the new offset.
+ */
 static int force_ibs_eilvt_setup(void)
 {
         int offset;
         int ret;
 
-        /*
-         * find the next free available EILVT entry, skip offset 0,
-         * pin search to this cpu
-         */
         preempt_disable();
+        /* find the next free available EILVT entry, skip offset 0 */
         for (offset = 1; offset < APIC_EILVT_NR_MAX; offset++) {
                 if (get_eilvt(offset))
                         break;
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index a3984f4ef192..f34b5b29fb95 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -141,6 +141,13 @@ static struct notifier_block module_load_nb = {
         .notifier_call = module_load_notify,
 };
 
+static void free_all_tasks(void)
+{
+        /* make sure we don't leak task structs */
+        process_task_mortuary();
+        process_task_mortuary();
+}
+
 int sync_start(void)
 {
         int err;
@@ -148,8 +155,6 @@ int sync_start(void)
         if (!zalloc_cpumask_var(&marked_cpus, GFP_KERNEL))
                 return -ENOMEM;
 
-        mutex_lock(&buffer_mutex);
-
         err = task_handoff_register(&task_free_nb);
         if (err)
                 goto out1;
@@ -166,7 +171,6 @@ int sync_start(void)
         start_cpu_work();
 
 out:
-        mutex_unlock(&buffer_mutex);
         return err;
 out4:
         profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
@@ -174,6 +178,7 @@ out3:
         profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
 out2:
         task_handoff_unregister(&task_free_nb);
+        free_all_tasks();
 out1:
         free_cpumask_var(marked_cpus);
         goto out;
@@ -182,20 +187,16 @@ out1:
 
 void sync_stop(void)
 {
-        /* flush buffers */
-        mutex_lock(&buffer_mutex);
         end_cpu_work();
         unregister_module_notifier(&module_load_nb);
         profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
         profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
         task_handoff_unregister(&task_free_nb);
-        mutex_unlock(&buffer_mutex);
-        flush_cpu_work();
+        barrier();                      /* do all of the above first */
 
-        /* make sure we don't leak task structs */
-        process_task_mortuary();
-        process_task_mortuary();
+        flush_cpu_work();
 
+        free_all_tasks();
         free_cpumask_var(marked_cpus);
 }
 
diff --git a/fs/dcookies.c b/fs/dcookies.c
index a21cabdbd87b..dda0dc702d1b 100644
--- a/fs/dcookies.c
+++ b/fs/dcookies.c
@@ -178,6 +178,8 @@ SYSCALL_DEFINE(lookup_dcookie)(u64 cookie64, char __user * buf, size_t len)
         /* FIXME: (deleted) ? */
         path = d_path(&dcs->path, kbuf, PAGE_SIZE);
 
+        mutex_unlock(&dcookie_mutex);
+
         if (IS_ERR(path)) {
                 err = PTR_ERR(path);
                 goto out_free;
@@ -194,6 +196,7 @@ SYSCALL_DEFINE(lookup_dcookie)(u64 cookie64, char __user * buf, size_t len)
 
 out_free:
         kfree(kbuf);
+        return err;
 out:
         mutex_unlock(&dcookie_mutex);
         return err;
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1ee417fcbfa5..908038f57440 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2740,7 +2740,7 @@ static int ftrace_process_regex(struct ftrace_hash *hash,
 {
         char *func, *command, *next = buff;
         struct ftrace_func_command *p;
-        int ret;
+        int ret = -EINVAL;
 
         func = strsep(&next, ":");
 
@@ -3330,6 +3330,7 @@ static int ftrace_process_locs(struct module *mod,
 {
         unsigned long *p;
         unsigned long addr;
+        unsigned long flags;
 
         mutex_lock(&ftrace_lock);
         p = start;
@@ -3346,7 +3347,13 @@ static int ftrace_process_locs(struct module *mod,
                 ftrace_record_ip(addr);
         }
 
+        /*
+         * Disable interrupts to prevent interrupts from executing
+         * code that is being modified.
+         */
+        local_irq_save(flags);
         ftrace_update_code(mod);
+        local_irq_restore(flags);
         mutex_unlock(&ftrace_lock);
 
         return 0;
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index f925c45f0afa..27d13b36b8be 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1870,8 +1870,12 @@ fs_initcall(init_kprobe_trace);
 
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 
-static int kprobe_trace_selftest_target(int a1, int a2, int a3,
-                                        int a4, int a5, int a6)
+/*
+ * The "__used" keeps gcc from removing the function symbol
+ * from the kallsyms table.
+ */
+static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
+                                               int a4, int a5, int a6)
 {
         return a1 + a2 + a3 + a4 + a5 + a6;
 }