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Diffstat (limited to 'kernel/trace/trace_functions_graph.c')
-rw-r--r--kernel/trace/trace_functions_graph.c82
1 files changed, 66 insertions, 16 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index b5c09242683..0b99120d395 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -82,9 +82,9 @@ static struct trace_array *graph_array;
* to fill in space into DURATION column.
*/
enum {
- DURATION_FILL_FULL = -1,
- DURATION_FILL_START = -2,
- DURATION_FILL_END = -3,
+ FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
+ FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
+ FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
};
static enum print_line_t
@@ -114,16 +114,37 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
return -EBUSY;
}
+ /*
+ * The curr_ret_stack is an index to ftrace return stack of
+ * current task. Its value should be in [0, FTRACE_RETFUNC_
+ * DEPTH) when the function graph tracer is used. To support
+ * filtering out specific functions, it makes the index
+ * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
+ * so when it sees a negative index the ftrace will ignore
+ * the record. And the index gets recovered when returning
+ * from the filtered function by adding the FTRACE_NOTRACE_
+ * DEPTH and then it'll continue to record functions normally.
+ *
+ * The curr_ret_stack is initialized to -1 and get increased
+ * in this function. So it can be less than -1 only if it was
+ * filtered out via ftrace_graph_notrace_addr() which can be
+ * set from set_graph_notrace file in debugfs by user.
+ */
+ if (current->curr_ret_stack < -1)
+ return -EBUSY;
+
calltime = trace_clock_local();
index = ++current->curr_ret_stack;
+ if (ftrace_graph_notrace_addr(func))
+ current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
barrier();
current->ret_stack[index].ret = ret;
current->ret_stack[index].func = func;
current->ret_stack[index].calltime = calltime;
current->ret_stack[index].subtime = 0;
current->ret_stack[index].fp = frame_pointer;
- *depth = index;
+ *depth = current->curr_ret_stack;
return 0;
}
@@ -137,7 +158,17 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
index = current->curr_ret_stack;
- if (unlikely(index < 0)) {
+ /*
+ * A negative index here means that it's just returned from a
+ * notrace'd function. Recover index to get an original
+ * return address. See ftrace_push_return_trace().
+ *
+ * TODO: Need to check whether the stack gets corrupted.
+ */
+ if (index < 0)
+ index += FTRACE_NOTRACE_DEPTH;
+
+ if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
ftrace_graph_stop();
WARN_ON(1);
/* Might as well panic, otherwise we have no where to go */
@@ -193,6 +224,15 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
trace.rettime = trace_clock_local();
barrier();
current->curr_ret_stack--;
+ /*
+ * The curr_ret_stack can be less than -1 only if it was
+ * filtered out and it's about to return from the function.
+ * Recover the index and continue to trace normal functions.
+ */
+ if (current->curr_ret_stack < -1) {
+ current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
+ return ret;
+ }
/*
* The trace should run after decrementing the ret counter
@@ -230,7 +270,7 @@ int __trace_graph_entry(struct trace_array *tr,
return 0;
entry = ring_buffer_event_data(event);
entry->graph_ent = *trace;
- if (!filter_current_check_discard(buffer, call, entry, event))
+ if (!call_filter_check_discard(call, entry, buffer, event))
__buffer_unlock_commit(buffer, event);
return 1;
@@ -259,10 +299,20 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
/* trace it when it is-nested-in or is a function enabled. */
if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
- ftrace_graph_ignore_irqs()) ||
+ ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
(max_depth && trace->depth >= max_depth))
return 0;
+ /*
+ * Do not trace a function if it's filtered by set_graph_notrace.
+ * Make the index of ret stack negative to indicate that it should
+ * ignore further functions. But it needs its own ret stack entry
+ * to recover the original index in order to continue tracing after
+ * returning from the function.
+ */
+ if (ftrace_graph_notrace_addr(trace->func))
+ return 1;
+
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
@@ -335,7 +385,7 @@ void __trace_graph_return(struct trace_array *tr,
return;
entry = ring_buffer_event_data(event);
entry->ret = *trace;
- if (!filter_current_check_discard(buffer, call, entry, event))
+ if (!call_filter_check_discard(call, entry, buffer, event))
__buffer_unlock_commit(buffer, event);
}
@@ -652,7 +702,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
}
/* No overhead */
- ret = print_graph_duration(DURATION_FILL_START, s, flags);
+ ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
if (ret != TRACE_TYPE_HANDLED)
return ret;
@@ -664,7 +714,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
- ret = print_graph_duration(DURATION_FILL_END, s, flags);
+ ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
if (ret != TRACE_TYPE_HANDLED)
return ret;
@@ -729,14 +779,14 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s,
return TRACE_TYPE_HANDLED;
/* No real adata, just filling the column with spaces */
- switch (duration) {
- case DURATION_FILL_FULL:
+ switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
+ case FLAGS_FILL_FULL:
ret = trace_seq_puts(s, " | ");
return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
- case DURATION_FILL_START:
+ case FLAGS_FILL_START:
ret = trace_seq_puts(s, " ");
return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
- case DURATION_FILL_END:
+ case FLAGS_FILL_END:
ret = trace_seq_puts(s, " |");
return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
}
@@ -852,7 +902,7 @@ print_graph_entry_nested(struct trace_iterator *iter,
}
/* No time */
- ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
+ ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
if (ret != TRACE_TYPE_HANDLED)
return ret;
@@ -1172,7 +1222,7 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
return TRACE_TYPE_PARTIAL_LINE;
/* No time */
- ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
+ ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
if (ret != TRACE_TYPE_HANDLED)
return ret;
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-04 23:52:46 +0000