Commit ab849b7f authored by Eli Zaretskii's avatar Eli Zaretskii
Browse files

Fix w32 memory-management problem when extending buffer text

* src/w32heap.c (mmap_realloc): Only attempt extending a region if
the following region has the same allocation base.  Also, use the
original allocation base and enlarged size to commit reserved
memory, to ensure that the allocation base stays at its original
value.  This fixes several hard-to-debug problems whereby part of
buffer text was overwritten with binary nulls, because
mmap_realloc copied only part of buffer text when extending it.
and for two
examples of the related problems.
parent 1b98a68b
......@@ -714,13 +714,12 @@ mmap_realloc (void **var, size_t nbytes)
/* If there is enough room in the current reserved area, then
commit more pages as needed. */
if (m2.State == MEM_RESERVE
&& m2.AllocationBase == memInfo.AllocationBase
&& nbytes <= memInfo.RegionSize + m2.RegionSize)
void *p;
p = VirtualAlloc (*var + memInfo.RegionSize,
nbytes - memInfo.RegionSize,
p = VirtualAlloc (*var, nbytes, MEM_COMMIT, PAGE_READWRITE);
if (!p /* && GetLastError() != ERROR_NOT_ENOUGH_MEMORY */)
DebPrint (("realloc enlarge: VirtualAlloc (%p + %I64x, %I64x) error %ld\n",
......@@ -728,7 +727,8 @@ mmap_realloc (void **var, size_t nbytes)
(uint64_t)(nbytes - memInfo.RegionSize),
GetLastError ()));
DebPrint (("next region: %p %p %I64x %x\n", m2.BaseAddress,
m2.AllocationBase, m2.RegionSize, m2.AllocationProtect));
m2.AllocationBase, (uint64_t)m2.RegionSize,
return *var;
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment