From ef241371de7c4546b3ad45d7d190965be735f998 Mon Sep 17 00:00:00 2001
From: GHC GitLab CI <ghc-ci@gitlab-haskell.org>
Date: Wed, 25 Nov 2020 23:08:50 +0000
Subject: [PATCH] nonmoving: Fix regression from TSAN work
The TSAN rework (specifically aad1f803) introduced a subtle regression
in GC.c, swapping `g0` in place of `gen`. Whoops!
Fixes #18997.
(cherry picked from commit 21c807df67afe1aee7bf4a964a00cc78ef19e00f)
---
rts/sm/GC.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/rts/sm/GC.c b/rts/sm/GC.c
index 6c947f06a93e..7a6345f469e9 100644
--- a/rts/sm/GC.c
+++ b/rts/sm/GC.c
@@ -1689,13 +1689,8 @@ collect_gct_blocks (void)
static void
collect_pinned_object_blocks (void)
{
- generation *gen;
const bool use_nonmoving = RtsFlags.GcFlags.useNonmoving;
- if (use_nonmoving && major_gc) {
- gen = oldest_gen;
- } else {
- gen = g0;
- }
+ generation *const gen = (use_nonmoving && major_gc) ? oldest_gen : g0;
for (uint32_t n = 0; n < n_capabilities; n++) {
bdescr *last = NULL;
@@ -1720,7 +1715,7 @@ collect_pinned_object_blocks (void)
if (gen->large_objects != NULL) {
gen->large_objects->u.back = last;
}
- g0->large_objects = RELAXED_LOAD(&capabilities[n]->pinned_object_blocks);
+ gen->large_objects = RELAXED_LOAD(&capabilities[n]->pinned_object_blocks);
RELAXED_STORE(&capabilities[n]->pinned_object_blocks, NULL);
}
}
--
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