Index: sys/external/bsd/drm2/include/linux/ww_mutex.h
===================================================================
RCS file: /cvsroot/src/sys/external/bsd/drm2/include/linux/ww_mutex.h,v
retrieving revision 1.6
diff -p -u -r1.6 ww_mutex.h
--- sys/external/bsd/drm2/include/linux/ww_mutex.h	13 Sep 2014 00:33:45 -0000	1.6
+++ sys/external/bsd/drm2/include/linux/ww_mutex.h	14 Sep 2014 23:33:46 -0000
@@ -51,6 +51,7 @@ struct ww_acquire_ctx {
 	unsigned	wwx_acquired;
 	bool		wwx_acquire_done;
 	struct rb_node	wwx_rb_node;
+	struct lwp	*wwx_owner;
 };
 
 static inline int
@@ -95,12 +96,17 @@ ww_acquire_init(struct ww_acquire_ctx *c
 	ctx->wwx_ticket = atomic_inc_64_nv(&class->wwc_ticket);
 	ctx->wwx_acquired = 0;
 	ctx->wwx_acquire_done = false;
+	ctx->wwx_owner = curlwp;
 }
 
 static inline void
 ww_acquire_done(struct ww_acquire_ctx *ctx)
 {
 
+	KASSERTMSG((ctx->wwx_owner == curlwp),
+	    "ctx %p owned by %p, not self (%p)", ctx, ctx->wwx_owner, curlwp);
+	printf("%s: ctx %p acquired %u\n", __func__, ctx, ctx->wwx_acquired);
+
 	ctx->wwx_acquire_done = true;
 }
 
@@ -108,9 +114,13 @@ static inline void
 ww_acquire_fini(struct ww_acquire_ctx *ctx)
 {
 
+	KASSERTMSG((ctx->wwx_owner == curlwp),
+	    "ctx %p owned by %p, not self (%p)", ctx, ctx->wwx_owner, curlwp);
 	KASSERTMSG((ctx->wwx_acquired == 0), "ctx %p still holds %u locks",
 	    ctx, ctx->wwx_acquired);
+
 	ctx->wwx_acquired = ~0U;	/* Fail if called again. */
+	ctx->wwx_owner = NULL;
 }
 
 struct ww_mutex {
@@ -349,7 +359,10 @@ ww_mutex_lock(struct ww_mutex *mutex, st
 		return 0;
 	}
 
+	KASSERTMSG((ctx->wwx_owner == curlwp),
+	    "ctx %p owned by %p, not self (%p)", ctx, ctx->wwx_owner, curlwp);
 	KASSERT(!ctx->wwx_acquire_done);
+	KASSERT(ctx->wwx_acquired != ~0U);
 
 	mutex_enter(&mutex->wwm_lock);
 retry:	switch (mutex->wwm_state) {
@@ -373,6 +386,8 @@ retry:	switch (mutex->wwm_state) {
 	}
 	KASSERT(mutex->wwm_state == WW_CTX);
 	KASSERT(mutex->wwm_u.ctx != NULL);
+	KASSERT((mutex->wwm_u.ctx == ctx) ||
+	    (mutex->wwm_u.ctx->wwx_owner != curlwp));
 	if (mutex->wwm_u.ctx == ctx) {
 		/*
 		 * We already own it.  Yes, this can happen correctly
@@ -416,7 +431,10 @@ ww_mutex_lock_interruptible(struct ww_mu
 	if (ctx == NULL)
 		return ww_mutex_lock_noctx_sig(mutex);
 
+	KASSERTMSG((ctx->wwx_owner == curlwp),
+	    "ctx %p owned by %p, not self (%p)", ctx, ctx->wwx_owner, curlwp);
 	KASSERT(!ctx->wwx_acquire_done);
+	KASSERT(ctx->wwx_acquired != ~0U);
 
 	mutex_enter(&mutex->wwm_lock);
 retry:	switch (mutex->wwm_state) {
@@ -444,6 +462,8 @@ retry:	switch (mutex->wwm_state) {
 	}
 	KASSERT(mutex->wwm_state == WW_CTX);
 	KASSERT(mutex->wwm_u.ctx != NULL);
+	KASSERT((mutex->wwm_u.ctx == ctx) ||
+	    (mutex->wwm_u.ctx->wwx_owner != curlwp));
 	if (mutex->wwm_u.ctx == ctx) {
 		/*
 		 * We already own it.  Yes, this can happen correctly
@@ -491,7 +511,10 @@ ww_mutex_lock_slow(struct ww_mutex *mute
 		return;
 	}
 
+	KASSERTMSG((ctx->wwx_owner == curlwp),
+	    "ctx %p owned by %p, not self (%p)", ctx, ctx->wwx_owner, curlwp);
 	KASSERT(!ctx->wwx_acquire_done);
+	KASSERT(ctx->wwx_acquired != ~0U);
 
 	mutex_enter(&mutex->wwm_lock);
 retry:	switch (mutex->wwm_state) {
@@ -515,6 +538,8 @@ retry:	switch (mutex->wwm_state) {
 	}
 	KASSERT(mutex->wwm_state == WW_CTX);
 	KASSERT(mutex->wwm_u.ctx != NULL);
+	KASSERTMSG((mutex->wwm_u.ctx->wwx_owner != curlwp),
+	    "locking against myself: %p", curlwp);
 	/*
 	 * Owned by another party, of any priority.  Ask that party to
 	 * wake us when it's done.
@@ -537,7 +562,10 @@ ww_mutex_lock_slow_interruptible(struct 
 	if (ctx == NULL)
 		return ww_mutex_lock_noctx_sig(mutex);
 
+	KASSERTMSG((ctx->wwx_owner == curlwp),
+	    "ctx %p owned by %p, not self (%p)", ctx, ctx->wwx_owner, curlwp);
 	KASSERT(!ctx->wwx_acquire_done);
+	KASSERT(ctx->wwx_acquired != ~0U);
 
 	mutex_enter(&mutex->wwm_lock);
 retry:	switch (mutex->wwm_state) {
@@ -565,6 +593,8 @@ retry:	switch (mutex->wwm_state) {
 	}
 	KASSERT(mutex->wwm_state == WW_CTX);
 	KASSERT(mutex->wwm_u.ctx != NULL);
+	KASSERTMSG((mutex->wwm_u.ctx->wwx_owner != curlwp),
+	    "locking against myself: %p", curlwp);
 	/*
 	 * Owned by another party, of any priority.  Ask that party to
 	 * wake us when it's done.
@@ -615,6 +645,11 @@ ww_mutex_unlock(struct ww_mutex *mutex)
 		break;
 	case WW_CTX:
 		KASSERT(mutex->wwm_u.ctx != NULL);
+		KASSERTMSG((mutex->wwm_u.ctx->wwx_owner == curlwp),
+		    "ww_mutex %p ctx %p held by %p, not by self (%p)",
+		    mutex, mutex->wwm_u.ctx, mutex->wwm_u.ctx->wwx_owner,
+		    curlwp);
+		KASSERT(mutex->wwm_u.ctx->wwx_acquired != ~0U);
 		mutex->wwm_u.ctx->wwx_acquired--;
 		mutex->wwm_u.ctx = NULL;
 		/*