doylet/DN
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix bug in arena stats on temp mem end

Browse Source
This commit is contained in:
doylet
2026-07-15 10:00:26 +10:00
parent 1e4ae8138e
commit fe150b3f36
3 changed files with 34 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Source/dn.cpp
+16 -7
View File
@@ -1467,8 +1467,8 @@ DN_API void DN_MemListPopTo(DN_MemList *mem, DN_U64 init_used)
if (!mem || !mem->curr)
return;
// NOTE: Free any memory blocks allocated additionally from the initial block to revert to
DN_U64 used = DN_Max(DN_ARENA_HEADER_SIZE, init_used);
// NOTE: Free any memory blocks until we get back to the starting block
DN_U64 used = DN_Max(DN_ARENA_HEADER_SIZE, init_used);
DN_MemBlock *curr = mem->curr;
while (curr->reserve_sum >= used) {
DN_MemBlock *block_to_free = curr;
@@ -1483,10 +1483,16 @@ DN_API void DN_MemListPopTo(DN_MemList *mem, DN_U64 init_used)
}
// NOTE: Revert the memory block we returned to
DN_U64 old_used = curr->used;
mem->stats.info.used = old_used;
mem->curr = curr;
curr->used = used - curr->reserve_sum;
DN_U64 old_used = curr->used;
mem->curr = curr;
// NOTE: Undo the used amount on the cumulative used count in the stats. This reverts the used
// number to how much memory has been used, not including this block.
mem->stats.info.used -= old_used;
// NOTE: Calculate the new correct used amount for this block after reversion and then apply it
curr->used = used - curr->reserve_sum;
mem->stats.info.used += curr->used;
// NOTE: Scrub memory that we used previously in the block but no longer after reverting
DN_MSVC_WARNING_PUSH
@@ -1517,7 +1523,6 @@ DN_API void DN_MemListPopTo(DN_MemList *mem, DN_U64 init_used)
DN_USize poison_size = ((char *)curr + curr->commit) - poison_ptr;
DN_ASanPoisonMemoryRegion(poison_ptr, poison_size);
}
mem->stats.info.used += curr->used;
}
DN_API void DN_MemListPop(DN_MemList *mem, DN_U64 amount)
@@ -1725,6 +1730,7 @@ DN_API DN_Arena DN_ArenaTempBeginFromArena(DN_Arena *arena)
DN_API void DN_ArenaTempEnd(DN_Arena *arena, DN_ArenaReset reset)
{
// NOTE: Do the UAF check
#if DN_ARENA_TEMP_MEM_UAF_GUARD
DN_AssertF(arena->uaf_guard_temp_mem, "Arena was not created with temp memory");
DN_ArenaUAFCheck_(arena, DN_ArenaUAFCheckReportType_TempEndOutOfOrder);
@@ -1732,6 +1738,7 @@ DN_API void DN_ArenaTempEnd(DN_Arena *arena, DN_ArenaReset reset)
DN_AssertF(arena->temp_mem.mem, "Arena was not created with temp memory");
#endif
// NOTE: Reset the arena
if (reset == DN_ArenaReset_Yes) {
#if DN_ARENA_TEMP_MEM_UAF_GUARD
DN_MemListTempEnd(*arena->uaf_guard_temp_mem);
@@ -1740,6 +1747,8 @@ DN_API void DN_ArenaTempEnd(DN_Arena *arena, DN_ArenaReset reset)
#endif
}
// NOTE: Pop the UAF guard off (note the UAF was allocated on the temp arena itself, so when we
// reset the arena, the old UAF guard has been deallocated).
#if DN_ARENA_TEMP_MEM_UAF_GUARD
DN_MemList *mem = arena->mem;
mem->uaf_guard_active_id = arena->uaf_guard_prev_id;