this_rq_is_locked() is introduced to check whether current CPU is holding
rq_lock(). This will be used in bpf/stackmap.c to decide whether is safe
to call up_read(), which may call rq_lock() for the same CPU.
Fixes: commit 615755a77b24 ("bpf: extend stackmap to save binary_build_id+offset instead of address")
Cc: stable@xxxxxxxxxxxxxxx # v4.17+
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
include/linux/sched.h | 1 +
kernel/sched/core.c | 8 ++++++++
2 files changed, 9 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2c2e56bd8913..fb0fcbd1b6f6 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1995,4 +1995,5 @@ int sched_trace_rq_cpu(struct rq *rq);
const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
+bool this_rq_is_locked(void);
#endif
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7880f4f64d0e..577cbe7c05fc 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -138,6 +138,14 @@ struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
}
}
+bool this_rq_is_locked(void)
+{
+ struct rq *rq;
+
+ rq = this_rq();
+ return raw_spin_is_locked(&rq->lock);
+}
+
/*
* RQ-clock updating methods:
*/
--
2.17.1
