From 24ef659a857c3cba40b64ea51ea4fce8d2fb7bbc Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 28 Oct 2013 09:22:24 -0700 Subject: rcu: Provide better diagnostics for blocking in RCU callback functions Currently blocking in an RCU callback function will result in "scheduling while atomic", which could be triggered for any number of reasons. To aid debugging, this patch introduces a rcu_callback_map that is used to tie the inappropriate voluntary context switch back to the fact that the function is being invoked from within a callback. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/rcu/rcu.h') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 7859a0a3951e..a8f981a2d110 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -102,13 +102,16 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head) { unsigned long offset = (unsigned long)head->func; + rcu_lock_acquire(&rcu_callback_map); if (__is_kfree_rcu_offset(offset)) { RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset)); kfree((void *)head - offset); + rcu_lock_release(&rcu_callback_map); return 1; } else { RCU_TRACE(trace_rcu_invoke_callback(rn, head)); head->func(head); + rcu_lock_release(&rcu_callback_map); return 0; } } -- cgit v1.2.3