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fix(database): abort P39 cascade recovery when pop_block() makes no progress (last write-lock deadlock loop) #118

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Merged
On1x merged 1 commit into from
Jun 16, 2026
Merged

fix(database): abort P39 cascade recovery when pop_block() makes no progress (last write-lock deadlock loop) #118

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14 changes: 14 additions & 0 deletions libraries/chain/database.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2422,7 +2422,21 @@ namespace graphene { namespace chain {
head_block_num() > lib_num) {
ilog("P39 cascade recovery: popping head #${h} (restoring to #${t})",
("h", head_block_num())("t", original_head));
block_id_type _pop_prev_id = head_block_id();
pop_block();
if (head_block_id() == _pop_prev_id) {
// pop_block() made no progress (committed/empty undo session
// while head is above LIB): undo() reverts nothing, so
// head_block_num() never decreases and neither loop condition
// can become false. Without this check the loop spins forever
// holding the global chainbase write lock — the same wedge
// fixed for the fork-switch loops in #117, here in the P39
// cascade-recovery path. Stop; the _fork_db.reset() below
// restores fork_db to the database head.
wlog("P39 cascade recovery: pop_block() made no progress at head #${h}. Stopping.",
("h", head_block_num()));
break;
}
}
_fork_db.reset();
if (head_blk) {
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