tracing: pass around ring buffer instead of tracer
The latency tracers (irqsoff and wakeup) can swap trace buffers
on the fly. If an event is happening and has reserved data on one of
the buffers, and the latency tracer swaps the global buffer with the
max buffer, the result is that the event may commit the data to the
wrong buffer.
This patch changes the API to the trace recording to be recieve the
buffer that was used to reserve a commit. Then this buffer can be passed
in to the commit.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0418e26..0c61836 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -169,10 +169,11 @@
static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
-int filter_current_check_discard(struct ftrace_event_call *call, void *rec,
+int filter_current_check_discard(struct ring_buffer *buffer,
+ struct ftrace_event_call *call, void *rec,
struct ring_buffer_event *event)
{
- return filter_check_discard(call, rec, global_trace.buffer, event);
+ return filter_check_discard(call, rec, buffer, event);
}
EXPORT_SYMBOL_GPL(filter_current_check_discard);
@@ -887,14 +888,15 @@
}
EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
-struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
- int type,
- unsigned long len,
- unsigned long flags, int pc)
+struct ring_buffer_event *
+trace_buffer_lock_reserve(struct ring_buffer *buffer,
+ int type,
+ unsigned long len,
+ unsigned long flags, int pc)
{
struct ring_buffer_event *event;
- event = ring_buffer_lock_reserve(tr->buffer, len);
+ event = ring_buffer_lock_reserve(buffer, len);
if (event != NULL) {
struct trace_entry *ent = ring_buffer_event_data(event);
@@ -905,53 +907,59 @@
return event;
}
-static inline void __trace_buffer_unlock_commit(struct trace_array *tr,
- struct ring_buffer_event *event,
- unsigned long flags, int pc,
- int wake)
+static inline void
+__trace_buffer_unlock_commit(struct ring_buffer *buffer,
+ struct ring_buffer_event *event,
+ unsigned long flags, int pc,
+ int wake)
{
- ring_buffer_unlock_commit(tr->buffer, event);
+ ring_buffer_unlock_commit(buffer, event);
- ftrace_trace_stack(tr, flags, 6, pc);
- ftrace_trace_userstack(tr, flags, pc);
+ ftrace_trace_stack(buffer, flags, 6, pc);
+ ftrace_trace_userstack(buffer, flags, pc);
if (wake)
trace_wake_up();
}
-void trace_buffer_unlock_commit(struct trace_array *tr,
- struct ring_buffer_event *event,
- unsigned long flags, int pc)
+void trace_buffer_unlock_commit(struct ring_buffer *buffer,
+ struct ring_buffer_event *event,
+ unsigned long flags, int pc)
{
- __trace_buffer_unlock_commit(tr, event, flags, pc, 1);
+ __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
}
struct ring_buffer_event *
-trace_current_buffer_lock_reserve(int type, unsigned long len,
+trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
+ int type, unsigned long len,
unsigned long flags, int pc)
{
- return trace_buffer_lock_reserve(&global_trace,
+ *current_rb = global_trace.buffer;
+ return trace_buffer_lock_reserve(*current_rb,
type, len, flags, pc);
}
EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
-void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
+void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
+ struct ring_buffer_event *event,
unsigned long flags, int pc)
{
- __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 1);
+ __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
}
EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
-void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event,
- unsigned long flags, int pc)
+void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
+ struct ring_buffer_event *event,
+ unsigned long flags, int pc)
{
- __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 0);
+ __trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
}
EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
-void trace_current_buffer_discard_commit(struct ring_buffer_event *event)
+void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
+ struct ring_buffer_event *event)
{
- ring_buffer_discard_commit(global_trace.buffer, event);
+ ring_buffer_discard_commit(buffer, event);
}
EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
@@ -961,6 +969,7 @@
int pc)
{
struct ftrace_event_call *call = &event_function;
+ struct ring_buffer *buffer = tr->buffer;
struct ring_buffer_event *event;
struct ftrace_entry *entry;
@@ -968,7 +977,7 @@
if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
return;
- event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
+ event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
flags, pc);
if (!event)
return;
@@ -976,8 +985,8 @@
entry->ip = ip;
entry->parent_ip = parent_ip;
- if (!filter_check_discard(call, entry, tr->buffer, event))
- ring_buffer_unlock_commit(tr->buffer, event);
+ if (!filter_check_discard(call, entry, buffer, event))
+ ring_buffer_unlock_commit(buffer, event);
}
void
@@ -990,7 +999,7 @@
}
#ifdef CONFIG_STACKTRACE
-static void __ftrace_trace_stack(struct trace_array *tr,
+static void __ftrace_trace_stack(struct ring_buffer *buffer,
unsigned long flags,
int skip, int pc)
{
@@ -999,7 +1008,7 @@
struct stack_entry *entry;
struct stack_trace trace;
- event = trace_buffer_lock_reserve(tr, TRACE_STACK,
+ event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
sizeof(*entry), flags, pc);
if (!event)
return;
@@ -1012,26 +1021,27 @@
trace.entries = entry->caller;
save_stack_trace(&trace);
- if (!filter_check_discard(call, entry, tr->buffer, event))
- ring_buffer_unlock_commit(tr->buffer, event);
+ if (!filter_check_discard(call, entry, buffer, event))
+ ring_buffer_unlock_commit(buffer, event);
}
-void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, int skip,
- int pc)
+void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
+ int skip, int pc)
{
if (!(trace_flags & TRACE_ITER_STACKTRACE))
return;
- __ftrace_trace_stack(tr, flags, skip, pc);
+ __ftrace_trace_stack(buffer, flags, skip, pc);
}
void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
int pc)
{
- __ftrace_trace_stack(tr, flags, skip, pc);
+ __ftrace_trace_stack(tr->buffer, flags, skip, pc);
}
-void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc)
+void
+ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
{
struct ftrace_event_call *call = &event_user_stack;
struct ring_buffer_event *event;
@@ -1041,7 +1051,7 @@
if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
return;
- event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
+ event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
sizeof(*entry), flags, pc);
if (!event)
return;
@@ -1055,8 +1065,8 @@
trace.entries = entry->caller;
save_stack_trace_user(&trace);
- if (!filter_check_discard(call, entry, tr->buffer, event))
- ring_buffer_unlock_commit(tr->buffer, event);
+ if (!filter_check_discard(call, entry, buffer, event))
+ ring_buffer_unlock_commit(buffer, event);
}
#ifdef UNUSED
@@ -1075,9 +1085,10 @@
{
struct ring_buffer_event *event;
struct trace_array *tr = __tr;
+ struct ring_buffer *buffer = tr->buffer;
struct special_entry *entry;
- event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
+ event = trace_buffer_lock_reserve(buffer, TRACE_SPECIAL,
sizeof(*entry), 0, pc);
if (!event)
return;
@@ -1085,7 +1096,7 @@
entry->arg1 = arg1;
entry->arg2 = arg2;
entry->arg3 = arg3;
- trace_buffer_unlock_commit(tr, event, 0, pc);
+ trace_buffer_unlock_commit(buffer, event, 0, pc);
}
void
@@ -1131,6 +1142,7 @@
struct ftrace_event_call *call = &event_bprint;
struct ring_buffer_event *event;
+ struct ring_buffer *buffer;
struct trace_array *tr = &global_trace;
struct trace_array_cpu *data;
struct bprint_entry *entry;
@@ -1163,7 +1175,9 @@
goto out_unlock;
size = sizeof(*entry) + sizeof(u32) * len;
- event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc);
+ buffer = tr->buffer;
+ event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
+ flags, pc);
if (!event)
goto out_unlock;
entry = ring_buffer_event_data(event);
@@ -1171,8 +1185,8 @@
entry->fmt = fmt;
memcpy(entry->buf, trace_buf, sizeof(u32) * len);
- if (!filter_check_discard(call, entry, tr->buffer, event))
- ring_buffer_unlock_commit(tr->buffer, event);
+ if (!filter_check_discard(call, entry, buffer, event))
+ ring_buffer_unlock_commit(buffer, event);
out_unlock:
__raw_spin_unlock(&trace_buf_lock);
@@ -1194,6 +1208,7 @@
struct ftrace_event_call *call = &event_print;
struct ring_buffer_event *event;
+ struct ring_buffer *buffer;
struct trace_array *tr = &global_trace;
struct trace_array_cpu *data;
int cpu, len = 0, size, pc;
@@ -1222,7 +1237,9 @@
trace_buf[len] = 0;
size = sizeof(*entry) + len + 1;
- event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
+ buffer = tr->buffer;
+ event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+ irq_flags, pc);
if (!event)
goto out_unlock;
entry = ring_buffer_event_data(event);
@@ -1230,8 +1247,8 @@
memcpy(&entry->buf, trace_buf, len);
entry->buf[len] = 0;
- if (!filter_check_discard(call, entry, tr->buffer, event))
- ring_buffer_unlock_commit(tr->buffer, event);
+ if (!filter_check_discard(call, entry, buffer, event))
+ ring_buffer_unlock_commit(buffer, event);
out_unlock:
__raw_spin_unlock(&trace_buf_lock);