Fix a LOR between sched_lock and sleep queue lock.

2 files changed, 8 insertions, 7 deletions

diff --git a/sys/kern/kern_kse.c b/sys/kern/kern_kse.c
index 5f49313..827fb66 100644
--- a/sys/kern/kern_kse.c
+++ b/sys/kern/kern_kse.c
@@ -707,8 +707,8 @@ kse_create(struct thread *td, struct kse_create_args *uap)
 	 * Make the new upcall available to the ksegrp.
 	 * It may or may not use it, but it's available.
 	 */
-	PROC_UNLOCK(p);
 	upcall_link(newku, newkg);
+	PROC_UNLOCK(p);
 	if (mbx.km_quantum)
 		newkg->kg_upquantum = max(1, mbx.km_quantum / tick);
 
@@ -1441,7 +1441,7 @@ thread_continued(struct proc *p)
 	struct thread *td;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
-	mtx_assert(&sched_lock, MA_OWNED);
+	KASSERT(P_SHOULDSTOP(p), "process not stopped");
 
 	if (!(p->p_flag & P_SA))
 		return;
@@ -1455,11 +1455,10 @@ thread_continued(struct proc *p)
 			if (!(td->td_pflags & TDP_SA))
 				continue;
 			FOREACH_UPCALL_IN_GROUP(kg, ku) {
+				mtx_lock_spin(&sched_lock);
 				ku->ku_flags |= KUF_DOUPCALL;
+				mtx_unlock_spin(&sched_lock);
 				wakeup(&kg->kg_completed);
-				if (TD_IS_SUSPENDED(ku->ku_owner)) {
-					thread_unsuspend_one(ku->ku_owner);
-				}	
 			}
 		}
 	}
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index 11b66da..f1157ca 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -788,7 +788,6 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 		/* deliver or queue signal */
 		if (P_SHOULDSTOP(p)) {
 			p->p_xstat = data;
-			p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG);
 			mtx_lock_spin(&sched_lock);
 			if (saved_pid <= PID_MAX) {
 				p->p_xthread->td_flags &= ~TDF_XSIG;
@@ -808,8 +807,11 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
 			 * you should use PT_SUSPEND to suspend it before
 			 * continuing process.
 			 */
-			thread_unsuspend(p);
+			mtx_unlock_spin(&sched_lock);
 			thread_continued(p);
+			p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG);
+			mtx_lock_spin(&sched_lock);
+			thread_unsuspend(p);
 			mtx_unlock_spin(&sched_lock);
 		} else if (data) {
 			psignal(p, data);