#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
static int tracing_set_tracer(struct trace_array *tr, const char *buf);
+static void ftrace_trace_userstack(struct ring_buffer *buffer,
+ unsigned long flags, int pc);
#define MAX_TRACER_SIZE 100
static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
* not modified.
*/
pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
- if (!pid_list)
+ if (!pid_list) {
+ trace_parser_put(&parser);
return -ENOMEM;
+ }
pid_list->pid_max = READ_ONCE(pid_max);
pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
if (!pid_list->pids) {
+ trace_parser_put(&parser);
kfree(pid_list);
return -ENOMEM;
}
#ifdef CONFIG_STACKTRACE
-#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
+/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
+#define FTRACE_KSTACK_NESTING 4
+
+#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
+
struct ftrace_stack {
- unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
+ unsigned long calls[FTRACE_KSTACK_ENTRIES];
};
-static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
+
+struct ftrace_stacks {
+ struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
+};
+
+static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
static DEFINE_PER_CPU(int, ftrace_stack_reserve);
static void __ftrace_trace_stack(struct ring_buffer *buffer,
{
struct trace_event_call *call = &event_kernel_stack;
struct ring_buffer_event *event;
+ unsigned int size, nr_entries;
+ struct ftrace_stack *fstack;
struct stack_entry *entry;
- struct stack_trace trace;
- int use_stack;
- int size = FTRACE_STACK_ENTRIES;
-
- trace.nr_entries = 0;
- trace.skip = skip;
+ int stackidx;
/*
* Add one, for this function and the call to save_stack_trace()
*/
#ifndef CONFIG_UNWINDER_ORC
if (!regs)
- trace.skip++;
+ skip++;
#endif
/*
*/
preempt_disable_notrace();
- use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
+ stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
+
+ /* This should never happen. If it does, yell once and skip */
+ if (WARN_ON_ONCE(stackidx > FTRACE_KSTACK_NESTING))
+ goto out;
+
/*
- * We don't need any atomic variables, just a barrier.
- * If an interrupt comes in, we don't care, because it would
- * have exited and put the counter back to what we want.
- * We just need a barrier to keep gcc from moving things
- * around.
+ * The above __this_cpu_inc_return() is 'atomic' cpu local. An
+ * interrupt will either see the value pre increment or post
+ * increment. If the interrupt happens pre increment it will have
+ * restored the counter when it returns. We just need a barrier to
+ * keep gcc from moving things around.
*/
barrier();
- if (use_stack == 1) {
- trace.entries = this_cpu_ptr(ftrace_stack.calls);
- trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
- if (regs)
- save_stack_trace_regs(regs, &trace);
- else
- save_stack_trace(&trace);
-
- if (trace.nr_entries > size)
- size = trace.nr_entries;
- } else
- /* From now on, use_stack is a boolean */
- use_stack = 0;
+ fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
+ size = ARRAY_SIZE(fstack->calls);
- size *= sizeof(unsigned long);
+ if (regs) {
+ nr_entries = stack_trace_save_regs(regs, fstack->calls,
+ size, skip);
+ } else {
+ nr_entries = stack_trace_save(fstack->calls, size, skip);
+ }
+ size = nr_entries * sizeof(unsigned long);
event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
sizeof(*entry) + size, flags, pc);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
- memset(&entry->caller, 0, size);
-
- if (use_stack)
- memcpy(&entry->caller, trace.entries,
- trace.nr_entries * sizeof(unsigned long));
- else {
- trace.max_entries = FTRACE_STACK_ENTRIES;
- trace.entries = entry->caller;
- if (regs)
- save_stack_trace_regs(regs, &trace);
- else
- save_stack_trace(&trace);
- }
-
- entry->size = trace.nr_entries;
+ memcpy(&entry->caller, fstack->calls, size);
+ entry->size = nr_entries;
if (!call_filter_check_discard(call, entry, buffer, event))
__buffer_unlock_commit(buffer, event);
}
EXPORT_SYMBOL_GPL(trace_dump_stack);
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
static DEFINE_PER_CPU(int, user_stack_count);
-void
+static void
ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
{
struct trace_event_call *call = &event_user_stack;
struct ring_buffer_event *event;
struct userstack_entry *entry;
- struct stack_trace trace;
if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE))
return;
entry->tgid = current->tgid;
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);
+ stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
if (!call_filter_check_discard(call, entry, buffer, event))
__buffer_unlock_commit(buffer, event);
out:
preempt_enable();
}
-
-#ifdef UNUSED
-static void __trace_userstack(struct trace_array *tr, unsigned long flags)
+#else /* CONFIG_USER_STACKTRACE_SUPPORT */
+static void ftrace_trace_userstack(struct ring_buffer *buffer,
+ unsigned long flags, int pc)
{
- ftrace_trace_userstack(tr, flags, preempt_count());
}
-#endif /* UNUSED */
+#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
#endif /* CONFIG_STACKTRACE */
struct ring_buffer *buffer;
void *page;
int cpu;
- int ref;
+ refcount_t refcount;
};
+static void buffer_ref_release(struct buffer_ref *ref)
+{
+ if (!refcount_dec_and_test(&ref->refcount))
+ return;
+ ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
+ kfree(ref);
+}
+
static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct buffer_ref *ref = (struct buffer_ref *)buf->private;
- if (--ref->ref)
- return;
-
- ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
- kfree(ref);
+ buffer_ref_release(ref);
buf->private = 0;
}
-static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
+static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct buffer_ref *ref = (struct buffer_ref *)buf->private;
- ref->ref++;
+ if (refcount_read(&ref->refcount) > INT_MAX/2)
+ return false;
+
+ refcount_inc(&ref->refcount);
+ return true;
}
/* Pipe buffer operations for a buffer. */
static const struct pipe_buf_operations buffer_pipe_buf_ops = {
.confirm = generic_pipe_buf_confirm,
.release = buffer_pipe_buf_release,
- .steal = generic_pipe_buf_steal,
+ .steal = generic_pipe_buf_nosteal,
.get = buffer_pipe_buf_get,
};
struct buffer_ref *ref =
(struct buffer_ref *)spd->partial[i].private;
- if (--ref->ref)
- return;
-
- ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
- kfree(ref);
+ buffer_ref_release(ref);
spd->partial[i].private = 0;
}
break;
}
- ref->ref = 1;
+ refcount_set(&ref->refcount, 1);
ref->buffer = iter->trace_buffer->buffer;
ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
if (IS_ERR(ref->page)) {
projects / linux-2.6-microblaze.git / blobdiff