From 6fbca24f33c2430b51c5413a7b4c85f4784b4d4c Mon Sep 17 00:00:00 2001 From: David McFarland Date: Mon, 17 Apr 2023 21:41:55 -0300 Subject: [PATCH] Cygwin: cygheap: fix fork error after heap has grown 2f9b8ff0 introduced a problem where forks would sometimes fail with: child_copy: cygheap read copy failed, 0x0..0x80044C750, done 0, windows pid 14032, Win32 error 299 When cygheap_max was > CYGHEAP_STORAGE_INITIAL, commit_size would be set to allocsize(cygheap_max), which is an address, not a size. VirtualAlloc would be called to commit commit_size bytes, which would fail, and then child_copy would be called with zero as the base address. Fixes: 2f9b8ff00cce ("Cygwin: decouple cygheap from Cygwin DLL") Signed-off-by: David McFarland --- winsup/cygwin/mm/cygheap.cc | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/winsup/cygwin/mm/cygheap.cc b/winsup/cygwin/mm/cygheap.cc index 609407656..4fda29d11 100644 --- a/winsup/cygwin/mm/cygheap.cc +++ b/winsup/cygwin/mm/cygheap.cc @@ -87,7 +87,8 @@ cygheap_fixup_in_child (bool execed) SIZE_T commit_size = CYGHEAP_STORAGE_INITIAL - CYGHEAP_STORAGE_LOW; if (child_proc_info->cygheap_max > (void *) CYGHEAP_STORAGE_INITIAL) - commit_size = allocsize (child_proc_info->cygheap_max); + commit_size = allocsize ((char *) child_proc_info->cygheap_max + - CYGHEAP_STORAGE_LOW); cygheap = (init_cygheap *) VirtualAlloc ((LPVOID) CYGHEAP_STORAGE_LOW, CYGHEAP_STORAGE_HIGH - CYGHEAP_STORAGE_LOW, -- 2.43.5