1 files changed, 182 insertions, 0 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4ee6f0375222..a45b59e53fbc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -30,6 +30,7 @@
 #include <linux/gfp.h>
 #include <linux/fs.h>
 #include <linux/kprobes.h>
+#include <linux/seq_file.h>
 #include <linux/writeback.h>
 
 #include <linux/stacktrace.h>
@@ -275,6 +276,8 @@ static const char *trace_options[] = {
         "ftrace_preempt",
         "branch",
         "annotate",
+        "userstacktrace",
+        "sym-userobj",
         NULL
 };
 
@@ -421,6 +424,28 @@ trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
         return trace_seq_putmem(s, hex, j);
 }
 
+static int
+trace_seq_path(struct trace_seq *s, struct path *path)
+{
+        unsigned char *p;
+
+        if (s->len >= (PAGE_SIZE - 1))
+                return 0;
+        p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
+        if (!IS_ERR(p)) {
+                p = mangle_path(s->buffer + s->len, p, "\n");
+                if (p) {
+                        s->len = p - s->buffer;
+                        return 1;
+                }
+        } else {
+                s->buffer[s->len++] = '?';
+                return 1;
+        }
+
+        return 0;
+}
+
 static void
 trace_seq_reset(struct trace_seq *s)
 {
@@ -661,6 +686,21 @@ static int trace_stop_count;
 static DEFINE_SPINLOCK(tracing_start_lock);
 
 /**
+ * ftrace_off_permanent - disable all ftrace code permanently
+ *
+ * This should only be called when a serious anomally has
+ * been detected.  This will turn off the function tracing,
+ * ring buffers, and other tracing utilites. It takes no
+ * locks and can be called from any context.
+ */
+void ftrace_off_permanent(void)
+{
+        tracing_disabled = 1;
+        ftrace_stop();
+        tracing_off_permanent();
+}
+
+/**
  * tracing_start - quick start of the tracer
  *
  * If tracing is enabled but was stopped by tracing_stop,
@@ -801,6 +841,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
 
         entry->preempt_count            = pc & 0xff;
         entry->pid                      = (tsk) ? tsk->pid : 0;
+        entry->tgid                     = (tsk) ? tsk->tgid : 0;
         entry->flags =
 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
                 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
@@ -918,6 +959,44 @@ void __trace_stack(struct trace_array *tr,
         ftrace_trace_stack(tr, data, flags, skip, preempt_count());
 }
 
+static void ftrace_trace_userstack(struct trace_array *tr,
+                   struct trace_array_cpu *data,
+                   unsigned long flags, int pc)
+{
+        struct ring_buffer_event *event;
+        struct userstack_entry *entry;
+        struct stack_trace trace;
+        unsigned long irq_flags;
+
+        if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
+                return;
+
+        event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
+                                         &irq_flags);
+        if (!event)
+                return;
+        entry   = ring_buffer_event_data(event);
+        tracing_generic_entry_update(&entry->ent, flags, pc);
+        entry->ent.type         = TRACE_USER_STACK;
+
+        memset(&entry->caller, 0, sizeof(entry->caller));
+
+        trace.nr_entries        = 0;
+        trace.max_entries       = FTRACE_STACK_ENTRIES;
+        trace.skip              = 0;
+        trace.entries           = entry->caller;
+
+        save_stack_trace_user(&trace);
+        ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+}
+
+void __trace_userstack(struct trace_array *tr,
+                   struct trace_array_cpu *data,
+                   unsigned long flags)
+{
+        ftrace_trace_userstack(tr, data, flags, preempt_count());
+}
+
 static void
 ftrace_trace_special(void *__tr, void *__data,
                      unsigned long arg1, unsigned long arg2, unsigned long arg3,
@@ -941,6 +1020,7 @@ ftrace_trace_special(void *__tr, void *__data,
         entry->arg3                     = arg3;
         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
         ftrace_trace_stack(tr, data, irq_flags, 4, pc);
+        ftrace_trace_userstack(tr, data, irq_flags, pc);
 
         trace_wake_up();
 }
@@ -979,6 +1059,7 @@ tracing_sched_switch_trace(struct trace_array *tr,
         entry->next_cpu = task_cpu(next);
         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
         ftrace_trace_stack(tr, data, flags, 5, pc);
+        ftrace_trace_userstack(tr, data, flags, pc);
 }
 
 void
@@ -1008,6 +1089,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
         entry->next_cpu                 = task_cpu(wakee);
         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
         ftrace_trace_stack(tr, data, flags, 6, pc);
+        ftrace_trace_userstack(tr, data, flags, pc);
 
         trace_wake_up();
 }
@@ -1387,6 +1469,78 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
         return ret;
 }
 
+static inline int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
+                                    unsigned long ip, unsigned long sym_flags)
+{
+        struct file *file = NULL;
+        unsigned long vmstart = 0;
+        int ret = 1;
+
+        if (mm) {
+                const struct vm_area_struct *vma;
+
+                down_read(&mm->mmap_sem);
+                vma = find_vma(mm, ip);
+                if (vma) {
+                        file = vma->vm_file;
+                        vmstart = vma->vm_start;
+                }
+                if (file) {
+                        ret = trace_seq_path(s, &file->f_path);
+                        if (ret)
+                                ret = trace_seq_printf(s, "[+0x%lx]", ip - vmstart);
+                }
+                up_read(&mm->mmap_sem);
+        }
+        if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
+                ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
+        return ret;
+}
+
+static int
+seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
+                      unsigned long sym_flags)
+{
+        struct mm_struct *mm = NULL;
+        int ret = 1;
+        unsigned int i;
+
+        if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
+                struct task_struct *task;
+                /*
+                 * we do the lookup on the thread group leader,
+                 * since individual threads might have already quit!
+                 */
+                rcu_read_lock();
+                task = find_task_by_vpid(entry->ent.tgid);
+                if (task)
+                        mm = get_task_mm(task);
+                rcu_read_unlock();
+        }
+
+        for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
+                unsigned long ip = entry->caller[i];
+
+                if (ip == ULONG_MAX || !ret)
+                        break;
+                if (i && ret)
+                        ret = trace_seq_puts(s, " <- ");
+                if (!ip) {
+                        if (ret)
+                                ret = trace_seq_puts(s, "??");
+                        continue;
+                }
+                if (!ret)
+                        break;
+                if (ret)
+                        ret = seq_print_user_ip(s, mm, ip, sym_flags);
+        }
+
+        if (mm)
+                mmput(mm);
+        return ret;
+}
+
 static void print_lat_help_header(struct seq_file *m)
 {
         seq_puts(m, "#                  _------=> CPU#            \n");
@@ -1702,6 +1856,15 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
                                  field->line);
                 break;
         }
+        case TRACE_USER_STACK: {
+                struct userstack_entry *field;
+
+                trace_assign_type(field, entry);
+
+                seq_print_userip_objs(field, s, sym_flags);
+                trace_seq_putc(s, '\n');
+                break;
+        }
         default:
                 trace_seq_printf(s, "Unknown type %d\n", entry->type);
         }
@@ -1853,6 +2016,19 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
                                  field->line);
                 break;
         }
+        case TRACE_USER_STACK: {
+                struct userstack_entry *field;
+
+                trace_assign_type(field, entry);
+
+                ret = seq_print_userip_objs(field, s, sym_flags);
+                if (!ret)
+                        return TRACE_TYPE_PARTIAL_LINE;
+                ret = trace_seq_putc(s, '\n');
+                if (!ret)
+                        return TRACE_TYPE_PARTIAL_LINE;
+                break;
+        }
         }
         return TRACE_TYPE_HANDLED;
 }
@@ -1912,6 +2088,7 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
                 break;
         }
         case TRACE_SPECIAL:
+        case TRACE_USER_STACK:
         case TRACE_STACK: {
                 struct special_entry *field;
 
@@ -2000,6 +2177,7 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
                 break;
         }
         case TRACE_SPECIAL:
+        case TRACE_USER_STACK:
         case TRACE_STACK: {
                 struct special_entry *field;
 
@@ -2054,6 +2232,7 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
                 break;
         }
         case TRACE_SPECIAL:
+        case TRACE_USER_STACK:
         case TRACE_STACK: {
                 struct special_entry *field;
 
@@ -3488,6 +3667,9 @@ void ftrace_dump(void)
                 atomic_inc(&global_trace.data[cpu]->disabled);
         }
 
+        /* don't look at user memory in panic mode */
+        trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
+
         printk(KERN_TRACE "Dumping ftrace buffer:\n");
 
         iter.tr = &global_trace;