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tracing: Use __this_cpu_read() in trace_event_buffer_lock_reserver()

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The value read by this_cpu_read() is used later and its use is expected to
stay on the same CPU as being read. But this_cpu_read() does not warn if
it is called without preemption disabled, where as __this_cpu_read() will
check if preemption is disabled on CONFIG_DEBUG_PREEMPT

Currently all callers have preemption disabled, but there may be new
callers in the future that may not.

Link: https://lkml.kernel.org/r/20211130024318.698165354@goodmis.org

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (VMware) 2021-11-29 21:39:46 -05:00
parent 7c689c8397
commit e07a1d5762
1 changed files with 1 additions and 1 deletions
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2
kernel/trace/trace.c
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@ -2746,7 +2746,7 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
if (!tr->no_filter_buffering_ref &&
(trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
(entry = this_cpu_read(trace_buffered_event))) {
(entry = __this_cpu_read(trace_buffered_event))) {
/*
* Filtering is on, so try to use the per cpu buffer first.
* This buffer will simulate a ring_buffer_event,