diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/rcupdate_trace.h | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h index fd3ddeb6aa3b..70decf877348 100644 --- a/include/linux/rcupdate_trace.h +++ b/include/linux/rcupdate_trace.h @@ -126,11 +126,13 @@ static inline void rcu_read_unlock_trace(void) struct srcu_ctr __percpu *scp; struct task_struct *t = current; - scp = t->trc_reader_scp; - barrier(); // scp before nesting to protect against interrupt handler. n = READ_ONCE(t->trc_reader_nesting) - 1; - WRITE_ONCE(t->trc_reader_nesting, n); - if (!n) { + if (n) { + WRITE_ONCE(t->trc_reader_nesting, n); + } else { + scp = t->trc_reader_scp; // Compiler cannot hoist load due to data raciness. + barrier(); // scp before nesting to protect against interrupt handler. + WRITE_ONCE(t->trc_reader_nesting, n); if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU_NO_MB)) smp_mb(); // Placeholder for more selective ordering __srcu_read_unlock_fast(&rcu_tasks_trace_srcu_struct, scp); |