From fdd3dcfa4eb0a4b17bb43f461a6790f68e76da41 Mon Sep 17 00:00:00 2001 From: Stefan Monnier Date: Wed, 1 Nov 2017 13:36:58 -0400 Subject: [PATCH] * src/alloc.c (sweep_symbols): Tweak last change Avoid the double-free without the extra check. Add an explanatory comment. --- src/alloc.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/src/alloc.c b/src/alloc.c index 11afdfd7cc0..3f4ec168fa3 100644 --- a/src/alloc.c +++ b/src/alloc.c @@ -7024,10 +7024,16 @@ sweep_symbols (void) { if (!sym->s.gcmarkbit) { - if (sym->s.redirect == SYMBOL_LOCALIZED - /* Already freed? */ - && !EQ (sym->s.function, Vdead)) - xfree (SYMBOL_BLV (&sym->s)); + if (sym->s.redirect == SYMBOL_LOCALIZED) + { + xfree (SYMBOL_BLV (&sym->s)); + /* At every GC we sweep all symbol_blocks and rebuild the + symbol_free_list, so those symbols which stayed unused + between the two will be re-swept. + So we have to make sure we don't re-free this blv next + time we sweep this symbol_block (bug#29066). */ + sym->s.redirect == SYMBOL_PLAINVAL; + } sym->s.next = symbol_free_list; symbol_free_list = &sym->s; symbol_free_list->function = Vdead; -- 2.39.2