From: Ken Brown <kbrown@cornell.edu>
To: cygwin@cygwin.com
Subject: Re: Threads
Date: Fri, 24 Oct 2014 01:07:00 -0000 [thread overview]
Message-ID: <5449A638.3080003@cornell.edu> (raw)
In-Reply-To: <544965F4.207@cornell.edu>
On 10/23/2014 4:32 PM, Ken Brown wrote:
> On 10/23/2014 11:37 AM, Corinna Vinschen wrote:
>> On Oct 23 08:04, Ken Brown wrote:
>>> On 10/23/2014 7:31 AM, Jon TURNEY wrote:
>>>> On 20/10/2014 14:03, Ken Brown wrote:
>>>>> Or is there some other plausible explanation for "impossible" crashes?
>>>>> This can't just be a result of a gdb bug, because in at least one case
>>>>> the assertion can be shown to be valid by using printf instead of gdb.
>>>>>
>>>>> [*] By "impossible" I mean that examination of the relevant
>>>>> variables in
>>>>> gdb shows that the assertions are in fact true. Two ongoing
>>>>> examples are
>>>>>
>>>>> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=18438
>>>>> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=18769
>>>>
>>>> As a suggestion, you might want to also take a careful look at how
>>>> signal
>>>> delivery is implemented in cygwin on x86_64
>>>>
>>>> I had a vague idea that there was, at some time in the past, a fix
>>>> made for
>>>> register corruption on x86_64 after a signal was handled, but I
>>>> can't find it
>>>> now, so maybe I imagined it.
>>>
>>> Is this what you're thinking of?
>>>
>>> https://cygwin.com/ml/cygwin-cvs/2014-q1/msg00020.html
>>>
>>>> But if for e.g. the flags register was getting
>>>> corrupted when a signal interrupts the main thread, that could
>>>> perhaps also
>>>> explain what is being seen.
>>>
>>> Yes, flags register corruption is exactly what Eli suggested in the
>>> other
>>> bug report I cited.
>>
>> The aforementioned patch was supposed to fix this problem and it is
>> definitely in the current 1.7.32 release...
>
> The ChangeLog entry just mentions the FPU control word and the XMM
> registers, but not the ordinary FLAGS register (or rather EFLAGS for x86
> and RFLAGS for x86_64, if I'm understanding correctly what I find in
> Wikipedia). Did the patch also take care of that?
Never mind, it looks like that was already OK before the patch. I see
that there are pushf and popf instructions in gendef.
Ken
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next prev parent reply other threads:[~2014-10-24 1:07 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-20 13:04 Threads Ken Brown
2014-10-20 16:43 ` Threads Corinna Vinschen
2014-10-20 19:03 ` Threads Corinna Vinschen
2014-10-20 19:58 ` Threads Ken Brown
2014-10-21 11:17 ` Threads Corinna Vinschen
2014-10-21 12:27 ` Threads Ken Brown
2014-10-23 11:31 ` Threads Jon TURNEY
2014-10-23 12:04 ` Threads Ken Brown
2014-10-23 15:37 ` Threads Corinna Vinschen
2014-10-23 18:07 ` Threads Achim Gratz
2014-10-23 20:32 ` Threads Ken Brown
2014-10-24 1:07 ` Ken Brown [this message]
2014-10-24 9:46 ` Threads Corinna Vinschen
2014-10-24 11:05 ` Threads Jon TURNEY
2014-10-24 12:54 ` Threads Corinna Vinschen
2014-10-24 13:52 ` Threads Corinna Vinschen
2014-10-26 11:58 ` Threads Ken Brown
2014-10-28 10:44 ` Threads Jon TURNEY
2014-10-28 11:40 ` Threads Corinna Vinschen
2014-10-28 13:47 ` Threads Ken Brown
2014-10-28 14:19 ` [GOLDSTARS] Threads Corinna Vinschen
2014-10-28 17:39 ` Andrew Schulman
2014-10-29 10:00 ` Corinna Vinschen
-- strict thread matches above, loose matches on Subject: below --
2014-10-26 13:20 Threads Angelo Graziosi
2014-10-26 21:38 ` Threads Ken Brown
2014-10-27 10:21 ` Threads Corinna Vinschen
2000-02-04 6:32 Threads M Dipperstein
2000-02-04 8:06 ` Threads Mumit Khan
1997-03-19 10:28 Threads Davind Maharaj
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