From 06252617b2c4cc9bcdd9407f1e709a7e0908cf27 Mon Sep 17 00:00:00 2001 From: Matt Armstrong Date: Wed, 19 Oct 2022 13:42:35 -0700 Subject: Revert "mark_overlays: Use the normal ITREE_FOREACH" This reverts commit b8fbd42f0a7caa4cd9e2d50dd4e4b2101ac78acd, with edits. * src/alloc.c (mark_overlays): restore function. (mark_buffer): Call it, not ITREE_FOREACH. (garbage_collect): eassert (!itree_busy_p ()). * src/itree.h: Comment tweak: explain why GC is considered risky. It isn't that GC itself is risky, it is that GC can call ELisp by way of a hook, and running ELisp during iteration is risks nested iteration. --- src/alloc.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'src/alloc.c') diff --git a/src/alloc.c b/src/alloc.c index 00f2991f250..d7e0a99ffe7 100644 --- a/src/alloc.c +++ b/src/alloc.c @@ -6279,6 +6279,11 @@ garbage_collect (void) image_prune_animation_caches (false); #endif + /* ELisp code run by `gc-post-hook' could result in itree iteration, + which must not happen while the itree is already busy. See + bug#58639. */ + eassert (!itree_iterator_busy_p ()); + if (!NILP (Vpost_gc_hook)) { specpdl_ref gc_count = inhibit_garbage_collection (); @@ -6510,6 +6515,18 @@ mark_overlay (struct Lisp_Overlay *ov) mark_object (ov->plist); } +/* Mark the overlay subtree rooted at NODE. */ + +static void +mark_overlays (struct interval_node *node) +{ + if (node == NULL) + return; + mark_object (node->data); + mark_overlays (node->left); + mark_overlays (node->right); +} + /* Mark Lisp_Objects and special pointers in BUFFER. */ static void @@ -6531,9 +6548,8 @@ mark_buffer (struct buffer *buffer) if (!BUFFER_LIVE_P (buffer)) mark_object (BVAR (buffer, undo_list)); - struct interval_node *node; - ITREE_FOREACH (node, buffer->overlays, PTRDIFF_MIN, PTRDIFF_MAX, ASCENDING) - mark_object (node->data); + if (buffer->overlays) + mark_overlays (buffer->overlays->root); /* If this is an indirect buffer, mark its base buffer. */ if (buffer->base_buffer && -- cgit v1.2.3