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tracing: Clear trace_state when starting trace

Clear trace_state data structure when starting trace in __synth_event_trace_start() internal function. Currently trace_state is initialized only in the synth_event_trace_start() API, but the trace_state in synth_event_trace() and synth_event_trace_array() are on the stack without initialization. This means those APIs will see wrong parameters and wil skip closing process in __synth_event_trace_end() because trace_state->disabled may be !0. Link: http://lkml.kernel.org/r/158193315899.8868.1781259176894639952.stgit@devnote2

Masami Hiramatsu committed 6 years ago

Commit 7ab215f1 parent 08d9e681 file · +2 −2Browse files

Showing the changes to kernel/trace (1 of 1 file). Show all

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kernel/trace/trace_events_hist.c+2−2
@@ -1824,6 +1824,8 @@ __synth_event_trace_start(struct trace_event_file *file, · 1823 unmodified lines
1824 int entry_size, fields_size = 0;1824 int entry_size, fields_size = 0;
1825 int ret = 0;1825 int ret = 0;
1826 1826
1827 memset(trace_state, '\0', sizeof(*trace_state));
1828
1827 /*1829 /*
1828 * Normal event tracing doesn't get called at all unless the1830 * Normal event tracing doesn't get called at all unless the
1829 * ENABLED bit is set (which attaches the probe thus allowing1831 * ENABLED bit is set (which attaches the probe thus allowing
@@ -2063,8 +2065,6 @@ int synth_event_trace_start(struct trace_event_file *file, · 233 unmodified lines
2063 if (!trace_state)2065 if (!trace_state)
2064 return -EINVAL;2066 return -EINVAL;
2065 2067
2066 memset(trace_state, '\0', sizeof(*trace_state));
2067
2068 ret = __synth_event_trace_start(file, trace_state);2068 ret = __synth_event_trace_start(file, trace_state);
2069 if (ret == -ENOENT)2069 if (ret == -ENOENT)
2070 ret = 0; /* just disabled, not really an error */2070 ret = 0; /* just disabled, not really an error */