From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Since the relative offset stacktrace requires a special module loading
events to decode binary, it should be an optional for normal use case.
User can enable this feature via `options/relative-stacktrace`.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
---
kernel/trace/trace.c | 13 ++++++++-----
kernel/trace/trace.h | 2 ++
kernel/trace/trace_entries.h | 22 ++++++++++++++++++++++
kernel/trace/trace_output.c | 37 ++++++++++++++++++++++++++++++++-----
4 files changed, 64 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8e86a43b368c..b4da5e29957f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2926,6 +2926,7 @@ static void __ftrace_trace_stack(struct trace_array *tr,
struct ftrace_stack *fstack;
struct stack_entry *entry;
int stackidx;
+ int type;
/*
* Add one, for this function and the call to save_stack_trace()
@@ -2937,6 +2938,7 @@ static void __ftrace_trace_stack(struct trace_array *tr,
#endif
preempt_disable_notrace();
+ type = (tr->trace_flags & TRACE_ITER_REL_STACK_BIT) ? TRACE_REL_STACK : TRACE_STACK;
stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
@@ -2973,17 +2975,18 @@ static void __ftrace_trace_stack(struct trace_array *tr,
for (int i = 0; i < nr_entries; i++) {
if (calls[i] >= tramp_start && calls[i] < tramp_end)
calls[i] = FTRACE_TRAMPOLINE_MARKER;
- else
+ else if (type == TRACE_REL_STACK)
calls[i] -= (unsigned long)_stext;
}
}
#else
- /* Adjsut entries as the offset from _stext, instead of raw address. */
- for (int i = 0; i < nr_entries; i++)
- fstack->calls[i] -= (unsigned long)_stext;
+ if (type == TRACE_REL_STACK)
+ /* Adjsut entries as the offset from _stext, instead of raw address. */
+ for (int i = 0; i < nr_entries; i++)
+ fstack->calls[i] -= (unsigned long)_stext;
#endif
- event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
+ event = __trace_buffer_lock_reserve(buffer, type,
struct_size(entry, caller, nr_entries),
trace_ctx);
if (!event)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9c21ba45b7af..602aea0ec69a 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -55,6 +55,7 @@ enum trace_type {
TRACE_TIMERLAT,
TRACE_RAW_DATA,
TRACE_FUNC_REPEATS,
+ TRACE_REL_STACK,
__TRACE_LAST_TYPE,
};
@@ -1350,6 +1351,7 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
C(TRACE_PRINTK, "trace_printk_dest"), \
C(PAUSE_ON_TRACE, "pause-on-trace"), \
C(HASH_PTR, "hash-ptr"), /* Print hashed pointer */ \
+ C(REL_STACK, "relative-stacktrace"), \
FUNCTION_FLAGS \
FGRAPH_FLAGS \
STACK_FLAGS \
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index fbfb396905a6..7769f95b70fe 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -229,6 +229,28 @@ FTRACE_ENTRY(kernel_stack, stack_entry,
(void *)__entry->caller[6], (void *)__entry->caller[7])
);
+FTRACE_ENTRY_DUP(kernel_rel_stack, stack_entry,
+
+ TRACE_REL_STACK,
+
+ F_STRUCT(
+ __field( int, size )
+ __stack_array( unsigned long, caller, FTRACE_STACK_ENTRIES, size)
+ ),
+
+ F_printk("\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+ "\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+ "\t=> %ps\n\t=> %ps\n",
+ (void *)__entry->caller[0] + (unsigned long)_stext,
+ (void *)__entry->caller[1] + (unsigned long)_stext,
+ (void *)__entry->caller[2] + (unsigned long)_stext,
+ (void *)__entry->caller[3] + (unsigned long)_stext,
+ (void *)__entry->caller[4] + (unsigned long)_stext,
+ (void *)__entry->caller[5] + (unsigned long)_stext,
+ (void *)__entry->caller[6] + (unsigned long)_stext,
+ (void *)__entry->caller[7] + (unsigned long)_stext)
+);
+
FTRACE_ENTRY(user_stack, userstack_entry,
TRACE_USER_STACK,
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 497872df48f6..47e4ab549e81 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -1239,16 +1239,17 @@ static struct trace_event trace_wake_event = {
.funcs = &trace_wake_funcs,
};
-/* TRACE_STACK */
-
-static enum print_line_t trace_stack_print(struct trace_iterator *iter,
- int flags, struct trace_event *event)
+static enum print_line_t trace_kernel_stack_print(struct trace_iterator *iter,
+ int flags, struct trace_event *event, bool relative)
{
struct stack_entry *field;
struct trace_seq *s = &iter->seq;
unsigned long *p;
unsigned long *end;
- long delta = (unsigned long)_stext + iter->tr->text_delta;
+ long delta = iter->tr->text_delta;
+
+ if (relative)
+ delta += (unsigned long)_stext;
trace_assign_type(field, iter->ent);
end = (unsigned long *)((long)iter->ent + iter->ent_size);
@@ -1272,6 +1273,14 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
return trace_handle_return(s);
}
+/* TRACE_STACK */
+
+static enum print_line_t trace_stack_print(struct trace_iterator *iter,
+ int flags, struct trace_event *event)
+{
+ return trace_kernel_stack_print(iter, flags, event, false);
+}
+
static struct trace_event_functions trace_stack_funcs = {
.trace = trace_stack_print,
};
@@ -1281,6 +1290,23 @@ static struct trace_event trace_stack_event = {
.funcs = &trace_stack_funcs,
};
+/* TRACE_REL_STACK */
+
+static enum print_line_t trace_rel_stack_print(struct trace_iterator *iter,
+ int flags, struct trace_event *event)
+{
+ return trace_kernel_stack_print(iter, flags, event, true);
+}
+
+static struct trace_event_functions trace_rel_stack_funcs = {
+ .trace = trace_rel_stack_print,
+};
+
+static struct trace_event trace_rel_stack_event = {
+ .type = TRACE_REL_STACK,
+ .funcs = &trace_rel_stack_funcs,
+};
+
/* TRACE_USER_STACK */
static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
int flags, struct trace_event *event)
@@ -1724,6 +1750,7 @@ static struct trace_event *events[] __initdata = {
&trace_ctx_event,
&trace_wake_event,
&trace_stack_event,
+ &trace_rel_stack_event,
&trace_user_stack_event,
&trace_bputs_event,
&trace_bprint_event,
