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Re: Threads

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

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?

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?


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