Re: Cygwin 3.4.3 and 3.5.0... hangs in make, top, procps, ls /proc/PID/...

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

Hi Takashi,

On Jan 16 23:45, Takashi Yano via Cygwin wrote:
> On Mon, 16 Jan 2023 11:23:54 +0100
> Corinna Vinschen wrote:
> > On Jan 16 18:02, Takashi Yano via Cygwin wrote:
> > [...]
> > > Errors seem to be three types: (null), cygpid.xxx and shared.5.
> > > I'm not sure what is happening and why at all, however, this
> > > did not seem to happen before the commit 30add3e6b3e3.
> > 
> > I'll try to reproduce this issue.  But the weird thing is certainly
> > this: The affected shared mem regions are apparently not the cygheap.
> > Rather, they are the "shared" and "cygpid" shared mem regions, which
> > should not at all collide with the cygheap.  I guess we need more
> > debug output in the api_fatal call inside open_shared...
> 
> I am now trying the test case with reverting the commit 60675f1a7eb2
> "Cygwin: decouple shared mem regions from Cygwin DLL", and the issue
> does not happen for several hours so far. I guess this most likely
> is the direct cause of the problem.

Actually, I' running your testcase on two machines in parallel now for
quite some time, which only one hunk of 60675f1a7eb2 reverted, i.e.

diff --git a/winsup/cygwin/mm/shared.cc b/winsup/cygwin/mm/shared.cc
index 893b20d289b4..6d6d2940b6d4 100644
--- a/winsup/cygwin/mm/shared.cc
+++ b/winsup/cygwin/mm/shared.cc
@@ -140,7 +140,11 @@ open_shared (const WCHAR *name, int n, HANDLE& shared_h, DWORD size,
   if (*m == SH_JUSTCREATE || *m == SH_JUSTOPEN)
     addr = NULL;
   else
-    addr = (void *) region_address[*m];
+    {
+      addr = (void *) region_address[*m];
+      VirtualFree (addr, 0, MEM_RELEASE);
+    }
+
 
   WCHAR map_buf[MAX_PATH];
   WCHAR *mapname = NULL;

So far (and knocking on wood madly while writing this) the mapping
problem didn't show up once.  Maybe you'd like to try the same?

Btw., I pinged you on IRC already 3 hours ago...


Corinna