On 12/26/2021 4:35 PM, Jeremy Drake wrote:
> On Sun, 26 Dec 2021, Ken Brown wrote:
> 
>> On 12/26/2021 11:04 AM, Ken Brown wrote:
>>> On 12/26/2021 10:09 AM, Ken Brown wrote:
>>>> 1. For some processes, NtQueryInformationProcess(ProcessHandleInformation)
>>>> can return STATUS_SUCCESS with invalid handle information.  See the
>>>> comment starting at line 5754, where it is shown how to detect this.
> 
> I kind of thought something like this (that NumberOfHandles was
> uninitialized memory).
> 
>>> If I'm right, the following patch should fix the problem:
>>>
>>> diff --git a/winsup/cygwin/fhandler_pipe.cc b/winsup/cygwin/fhandler_pipe.cc
>>> index ba6b70f55..4cef3e4ca 100644
>>> --- a/winsup/cygwin/fhandler_pipe.cc
>>> +++ b/winsup/cygwin/fhandler_pipe.cc
>>> @@ -1228,6 +1228,7 @@ fhandler_pipe::get_query_hdl_per_process (WCHAR *name,
>>>               HeapAlloc (GetProcessHeap (), 0, nbytes);
>>>             if (!phi)
>>>               goto close_proc;
>>> +         phi->NumberOfHandles = 0;
>>>             status = NtQueryInformationProcess (proc,
>>> ProcessHandleInformation,
>>>                                                 phi, nbytes, &len);
>>>             if (NT_SUCCESS (status))
>>
>> Actually, this first hunk should suffice.
>>
>>> Jeremy, could you try this?
>>>
>>> Ken
> 
> 
> I've built (leaving the assert in place too), and I've got 3 loops going
> on server 2022 and 1 going on ARM64.  So far so good.  I don't know how
> long before calling it good though.

Great, thanks for testing.  I'm attaching the complete patch (with 
documentation).  I'll push it once you're convinced that it fixes the problem, 
assuming Takashi agrees.  (I think Corinna is unavailable.)

Ken