Commit-ID: 77c60400c82bd9935de08ea133e761a7e996bb82
Gitweb: http://git.kernel.org/tip/77c60400c82bd9935de08ea133e761a7e996bb82
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Mon, 24 Apr 2017 22:54:20 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 24 Apr 2017 22:54:20 +0200
trace: Prevent CPU hotplug in trace_event_enable_cmd_record()
The lockdep assertion in __static_key_slow_inc() triggers from the
following call chain:
__static_key_slow_inc+0xae/0xf4
static_key_slow_inc_cpuslocked+0x8/0xa
tracepoint_probe_register_prio+0x38d/0x3aa
tracepoint_probe_register+0xa/0xc
tracing_start_cmdline_record+0x4c/0x111
trace_printk_start_comm+0x28/0x2a
trace_event_init+0x1e0/0x1ed
trace_init+0x410/0x417
trace_event_enable_cmd_record() which is the actual caller of
tracepoint_probe_register() lacks the hotplug protection. Add it.
Reported-by: Xiaolong Ye <xiaolong.ye@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_events.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 8156bfd..4330b1d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -326,6 +326,7 @@ void trace_event_enable_cmd_record(bool enable)
struct trace_event_file *file;
struct trace_array *tr;
+ get_online_cpus();
mutex_lock(&event_mutex);
do_for_each_event_file(tr, file) {
@@ -341,6 +342,7 @@ void trace_event_enable_cmd_record(bool enable)
}
} while_for_each_event_file();
mutex_unlock(&event_mutex);
+ put_online_cpus();
}
static int __ftrace_event_enable_disable(struct trace_event_file *file,
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|