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authorLinus Torvalds <torvalds@linux-foundation.org>2017-05-20 23:39:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-20 23:39:03 -0700
commit56f410cf45a1c1f68f77741990e0435b06a07676 (patch)
treeb52f55cd45228474818b5409b722255a0a24ed24 /kernel
parent894e21642dde19184f059c485c49abd7ecdd6ec9 (diff)
parenta33d7d94eed92b23fbbc7b0de06a41b2bbaa49e3 (diff)
Merge tag 'trace-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt: - Fix a bug caused by not cleaning up the new instance unique triggers when deleting an instance. It also creates a selftest that triggers that bug. - Fix the delayed optimization happening after kprobes boot up self tests being removed by freeing of init memory. - Comment kprobes on why the delay optimization is not a problem for removal of modules, to keep other developers from searching that riddle. - Fix another case of rcu not watching in stack trace tracing. * tag 'trace-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Make sure RCU is watching before calling a stack trace kprobes: Document how optimized kprobes are removed from module unload selftests/ftrace: Add test to remove instance with active event triggers selftests/ftrace: Fix bashisms ftrace: Remove #ifdef from code and add clear_ftrace_function_probes() stub ftrace/instances: Clear function triggers when removing instances ftrace: Simplify glob handling in unregister_ftrace_function_probe_func() tracing/kprobes: Enforce kprobes teardown after testing tracing: Move postpone selftests to core from early_initcall
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c8
-rw-r--r--kernel/trace/ftrace.c12
-rw-r--r--kernel/trace/trace.c34
-rw-r--r--kernel/trace/trace.h5
-rw-r--r--kernel/trace/trace_kprobe.c5
5 files changed, 59 insertions, 5 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 7367e0ec6f81..2d2d3a568e4e 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -595,7 +595,7 @@ static void kprobe_optimizer(struct work_struct *work)
}
/* Wait for completing optimization and unoptimization */
-static void wait_for_kprobe_optimizer(void)
+void wait_for_kprobe_optimizer(void)
{
mutex_lock(&kprobe_mutex);
@@ -2183,6 +2183,12 @@ static int kprobes_module_callback(struct notifier_block *nb,
* The vaddr this probe is installed will soon
* be vfreed buy not synced to disk. Hence,
* disarming the breakpoint isn't needed.
+ *
+ * Note, this will also move any optimized probes
+ * that are pending to be removed from their
+ * corresponding lists to the freeing_list and
+ * will not be touched by the delayed
+ * kprobe_optimizer work handler.
*/
kill_kprobe(p);
}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 39dca4e86a94..74fdfe9ed3db 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4144,9 +4144,9 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
int i, ret = -ENODEV;
int size;
- if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
+ if (!glob || !strlen(glob) || !strcmp(glob, "*"))
func_g.search = NULL;
- else if (glob) {
+ else {
int not;
func_g.type = filter_parse_regex(glob, strlen(glob),
@@ -4256,6 +4256,14 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
return ret;
}
+void clear_ftrace_function_probes(struct trace_array *tr)
+{
+ struct ftrace_func_probe *probe, *n;
+
+ list_for_each_entry_safe(probe, n, &tr->func_probes, list)
+ unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
+}
+
static LIST_HEAD(ftrace_commands);
static DEFINE_MUTEX(ftrace_cmd_mutex);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c4536c449021..1122f151466f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1558,7 +1558,7 @@ static __init int init_trace_selftests(void)
return 0;
}
-early_initcall(init_trace_selftests);
+core_initcall(init_trace_selftests);
#else
static inline int run_tracer_selftest(struct tracer *type)
{
@@ -2568,7 +2568,36 @@ static inline void ftrace_trace_stack(struct trace_array *tr,
void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
int pc)
{
- __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
+ struct ring_buffer *buffer = tr->trace_buffer.buffer;
+
+ if (rcu_is_watching()) {
+ __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
+ return;
+ }
+
+ /*
+ * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
+ * but if the above rcu_is_watching() failed, then the NMI
+ * triggered someplace critical, and rcu_irq_enter() should
+ * not be called from NMI.
+ */
+ if (unlikely(in_nmi()))
+ return;
+
+ /*
+ * It is possible that a function is being traced in a
+ * location that RCU is not watching. A call to
+ * rcu_irq_enter() will make sure that it is, but there's
+ * a few internal rcu functions that could be traced
+ * where that wont work either. In those cases, we just
+ * do nothing.
+ */
+ if (unlikely(rcu_irq_enter_disabled()))
+ return;
+
+ rcu_irq_enter_irqson();
+ __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
+ rcu_irq_exit_irqson();
}
/**
@@ -7550,6 +7579,7 @@ static int instance_rmdir(const char *name)
}
tracing_set_nop(tr);
+ clear_ftrace_function_probes(tr);
event_trace_del_tracer(tr);
ftrace_clear_pids(tr);
ftrace_destroy_function_files(tr);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 291a1bca5748..39fd77330aab 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -980,6 +980,7 @@ register_ftrace_function_probe(char *glob, struct trace_array *tr,
extern int
unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
struct ftrace_probe_ops *ops);
+extern void clear_ftrace_function_probes(struct trace_array *tr);
int register_ftrace_command(struct ftrace_func_command *cmd);
int unregister_ftrace_command(struct ftrace_func_command *cmd);
@@ -998,6 +999,10 @@ static inline __init int unregister_ftrace_command(char *cmd_name)
{
return -EINVAL;
}
+static inline void clear_ftrace_function_probes(struct trace_array *tr)
+{
+}
+
/*
* The ops parameter passed in is usually undefined.
* This must be a macro.
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 8485f6738a87..c129fca6ec99 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1535,6 +1535,11 @@ static __init int kprobe_trace_self_tests_init(void)
end:
release_all_trace_kprobes();
+ /*
+ * Wait for the optimizer work to finish. Otherwise it might fiddle
+ * with probes in already freed __init text.
+ */
+ wait_for_kprobe_optimizer();
if (warn)
pr_cont("NG: Some tests are failed. Please check them.\n");
else