From 0ec1bd64b3317febe8c018041f538f1c83135e6c Mon Sep 17 00:00:00 2001
From: Ben Gamari <bgamari.foss@gmail.com>
Date: Sat, 7 Apr 2018 13:32:04 -0400
Subject: [PATCH] rts/RetainerProfile: Handle BLOCKING_QUEUES

push() considers BLOCKING_QUEUES to be an invalid closure type which
should never be present on the stack. However, retainClosure made no
accomodation for this and ended up pushing such a closure. This lead
to #14947.

Test Plan: Validate

Reviewers: simonmar, erikd

Reviewed By: simonmar

Subscribers: thomie, carter, RyanGlScott

GHC Trac Issues: #14947

Differential Revision: https://phabricator.haskell.org/D4538

(cherry picked from commit d5f6d7a03d66a93ec05a90948126feffc9279dc6)
---
 rts/RetainerProfile.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/rts/RetainerProfile.c b/rts/RetainerProfile.c
index 7a9b9ccd5427..67cba8393ee8 100644
--- a/rts/RetainerProfile.c
+++ b/rts/RetainerProfile.c
@@ -426,7 +426,7 @@ find_srt( stackPos *info )
  *  push() pushes a stackElement representing the next child of *c
  *  onto the traverse stack. If *c has no child, *first_child is set
  *  to NULL and nothing is pushed onto the stack. If *c has only one
- *  child, *c_chlid is set to that child and nothing is pushed onto
+ *  child, *c_child is set to that child and nothing is pushed onto
  *  the stack.  If *c has more than two children, *first_child is set
  *  to the first child and a stackElement representing the second
  *  child is pushed onto the stack.
@@ -1706,6 +1706,15 @@ inner_loop:
         goto loop;
     }
 
+    case BLOCKING_QUEUE:
+    {
+        StgBlockingQueue *bq = (StgBlockingQueue *)c;
+        retainClosure((StgClosure*) bq->link,           c, c_child_r);
+        retainClosure((StgClosure*) bq->bh,             c, c_child_r);
+        retainClosure((StgClosure*) bq->owner,          c, c_child_r);
+        goto loop;
+    }
+
     case PAP:
     {
         StgPAP *pap = (StgPAP *)c;
-- 
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