[newlib-cygwin] Cygwin: cygheap: Initialize myself_pinfo before child_copy().

Takashi Yano tyan0@sourceware.org
Tue Jan 10 13:15:47 GMT 2023


https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=a81fef51cf9f1b9fad73ad85826f02f40d85fda6

commit a81fef51cf9f1b9fad73ad85826f02f40d85fda6
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Tue Jan 10 21:04:29 2023 +0900

    Cygwin: cygheap: Initialize myself_pinfo before child_copy().
    
    After the commit 30add3e6b3e3, the problem:
    https://cygwin.com/pipermail/cygwin/2022-December/252759.html
    occurs rarely. It seems that myself_pinfo should be initialized
    where the timing before child_copy() and after cygheap allocation.
    This patch moves the initialization there.
    
    Fixes: 30add3e6b3e3 ("Cygwin: exec: don't access cygheap before it's
    initialized")
    Reported-by: Brian Inglis <Brian.Inglis@Shaw.ca>
    Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
    Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

Diff:
---
 winsup/cygwin/dcrt0.cc      | 2 --
 winsup/cygwin/mm/cygheap.cc | 2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 5c5a280cc..49b7a44ae 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -631,8 +631,6 @@ child_info_spawn::handle_spawn ()
   if (!dynamically_loaded || get_parent_handle ())
       {
 	cygheap_fixup_in_child (true);
-	if (dynamically_loaded)
-	  moreinfo->myself_pinfo = NULL;
 	memory_init ();
       }
 
diff --git a/winsup/cygwin/mm/cygheap.cc b/winsup/cygwin/mm/cygheap.cc
index 72861d8d7..6a20c159a 100644
--- a/winsup/cygwin/mm/cygheap.cc
+++ b/winsup/cygwin/mm/cygheap.cc
@@ -95,6 +95,8 @@ cygheap_fixup_in_child (bool execed)
   cygheap = (init_cygheap *) VirtualAlloc ((LPVOID) CYGHEAP_STORAGE_LOW,
 					   commit_size, MEM_COMMIT,
 					   PAGE_READWRITE);
+  if (dynamically_loaded && execed)
+    spawn_info->moreinfo->myself_pinfo = NULL;
   cygheap_max = child_proc_info->cygheap_max;
   child_copy (child_proc_info->parent, false, child_proc_info->silentfail (),
 	      "cygheap", cygheap, cygheap_max, NULL);


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