190 lines
4.8 KiB
Diff
190 lines
4.8 KiB
Diff
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
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Date: Fri, 22 Sep 2017 14:58:16 -0500
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Subject: [PATCH 02/42] tracing: Reverse the order of trace_types_lock and
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event_mutex
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patches-4.14.15-rt13.tar.xz
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In order to make future changes where we need to call
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tracing_set_clock() from within an event command, the order of
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trace_types_lock and event_mutex must be reversed, as the event command
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will hold event_mutex and the trace_types_lock is taken from within
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tracing_set_clock().
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Requested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
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Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/trace/trace.c | 5 +++++
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kernel/trace/trace_events.c | 31 +++++++++++++++----------------
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2 files changed, 20 insertions(+), 16 deletions(-)
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--- a/kernel/trace/trace.c
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+++ b/kernel/trace/trace.c
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@@ -7671,6 +7671,7 @@ static int instance_mkdir(const char *na
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struct trace_array *tr;
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int ret;
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+ mutex_lock(&event_mutex);
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mutex_lock(&trace_types_lock);
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ret = -EEXIST;
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@@ -7726,6 +7727,7 @@ static int instance_mkdir(const char *na
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list_add(&tr->list, &ftrace_trace_arrays);
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mutex_unlock(&trace_types_lock);
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+ mutex_unlock(&event_mutex);
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return 0;
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@@ -7737,6 +7739,7 @@ static int instance_mkdir(const char *na
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out_unlock:
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mutex_unlock(&trace_types_lock);
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+ mutex_unlock(&event_mutex);
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return ret;
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@@ -7749,6 +7752,7 @@ static int instance_rmdir(const char *na
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int ret;
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int i;
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+ mutex_lock(&event_mutex);
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mutex_lock(&trace_types_lock);
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ret = -ENODEV;
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@@ -7794,6 +7798,7 @@ static int instance_rmdir(const char *na
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out_unlock:
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mutex_unlock(&trace_types_lock);
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+ mutex_unlock(&event_mutex);
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return ret;
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}
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--- a/kernel/trace/trace_events.c
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+++ b/kernel/trace/trace_events.c
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@@ -1406,8 +1406,8 @@ static int subsystem_open(struct inode *
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return -ENODEV;
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/* Make sure the system still exists */
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- mutex_lock(&trace_types_lock);
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mutex_lock(&event_mutex);
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+ mutex_lock(&trace_types_lock);
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list_for_each_entry(tr, &ftrace_trace_arrays, list) {
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list_for_each_entry(dir, &tr->systems, list) {
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if (dir == inode->i_private) {
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@@ -1421,8 +1421,8 @@ static int subsystem_open(struct inode *
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}
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}
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exit_loop:
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- mutex_unlock(&event_mutex);
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mutex_unlock(&trace_types_lock);
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+ mutex_unlock(&event_mutex);
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if (!system)
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return -ENODEV;
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@@ -2308,15 +2308,15 @@ static void __add_event_to_tracers(struc
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int trace_add_event_call(struct trace_event_call *call)
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{
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int ret;
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- mutex_lock(&trace_types_lock);
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mutex_lock(&event_mutex);
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+ mutex_lock(&trace_types_lock);
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ret = __register_event(call, NULL);
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if (ret >= 0)
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__add_event_to_tracers(call);
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- mutex_unlock(&event_mutex);
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mutex_unlock(&trace_types_lock);
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+ mutex_unlock(&event_mutex);
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return ret;
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}
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@@ -2370,13 +2370,13 @@ int trace_remove_event_call(struct trace
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{
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int ret;
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- mutex_lock(&trace_types_lock);
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mutex_lock(&event_mutex);
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+ mutex_lock(&trace_types_lock);
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down_write(&trace_event_sem);
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ret = probe_remove_event_call(call);
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up_write(&trace_event_sem);
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- mutex_unlock(&event_mutex);
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mutex_unlock(&trace_types_lock);
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+ mutex_unlock(&event_mutex);
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return ret;
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}
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@@ -2438,8 +2438,8 @@ static int trace_module_notify(struct no
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{
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struct module *mod = data;
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- mutex_lock(&trace_types_lock);
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mutex_lock(&event_mutex);
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+ mutex_lock(&trace_types_lock);
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switch (val) {
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case MODULE_STATE_COMING:
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trace_module_add_events(mod);
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@@ -2448,8 +2448,8 @@ static int trace_module_notify(struct no
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trace_module_remove_events(mod);
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break;
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}
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- mutex_unlock(&event_mutex);
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mutex_unlock(&trace_types_lock);
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+ mutex_unlock(&event_mutex);
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return 0;
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}
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@@ -2964,24 +2964,24 @@ create_event_toplevel_files(struct dentr
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* creates the event hierachry in the @parent/events directory.
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*
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* Returns 0 on success.
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+ *
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+ * Must be called with event_mutex held.
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*/
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int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
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{
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int ret;
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- mutex_lock(&event_mutex);
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+ lockdep_assert_held(&event_mutex);
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ret = create_event_toplevel_files(parent, tr);
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if (ret)
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- goto out_unlock;
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+ goto out;
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down_write(&trace_event_sem);
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__trace_add_event_dirs(tr);
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up_write(&trace_event_sem);
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- out_unlock:
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- mutex_unlock(&event_mutex);
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-
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+ out:
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return ret;
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}
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@@ -3010,9 +3010,10 @@ early_event_add_tracer(struct dentry *pa
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return ret;
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}
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+/* Must be called with event_mutex held */
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int event_trace_del_tracer(struct trace_array *tr)
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{
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- mutex_lock(&event_mutex);
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+ lockdep_assert_held(&event_mutex);
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/* Disable any event triggers and associated soft-disabled events */
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clear_event_triggers(tr);
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@@ -3033,8 +3034,6 @@ int event_trace_del_tracer(struct trace_
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tr->event_dir = NULL;
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- mutex_unlock(&event_mutex);
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-
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return 0;
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}
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