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Re: [commit/windows] Add thread ID in SuspendThread error warning message.
- From: Joel Brobecker <brobecker at adacore dot com>
- To: gdb-patches at sourceware dot org, Eli Zaretskii <eliz at gnu dot org>
- Date: Mon, 24 Jun 2013 16:34:21 -0700
- Subject: Re: [commit/windows] Add thread ID in SuspendThread error warning message.
- References: <1370946106-7883-1-git-send-email-brobecker at adacore dot com> <8338somyrk dot fsf at gnu dot org> <20130611162738 dot GN3969 at adacore dot com> <83ppvslgrq dot fsf at gnu dot org> <20130618180156 dot GA7035 at ednor dot casa dot cgf dot cx> <20130618234349 dot GH5560 at adacore dot com> <20130620184223 dot GA6474 at ednor dot casa dot cgf dot cx>
> >That's interesting. I have the following patch in AdaCore's tree
> >which I have been uhming and ahming about. Would it apply to your
> >situation as well?
> >
> >- warning (_("SuspendThread failed. (winerr %u)"),
> >- (unsigned) err);
> >- return NULL;
> >+ /* If SuspendThread failed with error 5 (access
> >+ denied), then ignore the error. It's unclear
> >+ where this comes from and how to prevent it.
> >+ But in the meantime, ignoring it seems to allow
> >+ us to inspect the thread (including fetching
> >+ registers) without apparent ill effect. */
> >+ if (err != 5)
> >+ {
> >+ warning (_("SuspendThread (tid=0x%x) failed."
> >+ " (winerr %d)"),
> >+ (unsigned) id, (unsigned) err);
> >+ return NULL;
> >+ }
>
> That's basically what I'm doing in the Cygwin release:
>
> if (SuspendThread (th->h) == (DWORD) -1)
> {
> DWORD err = GetLastError ();
> - warning (_("SuspendThread failed. (winerr %u)"),
> - (unsigned) err);
> + /* Can get a ERROR_INVALID_HANDLE if the main thread has
> + exited. */
> + if (err != ERROR_INVALID_HANDLE)
> + warning (_("SuspendThread(%p) failed. (winerr %u)"),
> + (void *) th->h, (unsigned) err);
> return NULL;
> }
> th->suspended = 1;
That's interesting again. If I read MSDN right, ERROR_INVALID_HANDLE
is 6, whereas I ignore the error for code 5 (access denied). I say
that it's interesting, because the report we had was for the error
you ignore.
Someone was able to reproduce this issue consistently, and I wish
they had more time to help me investigate this. If we had more
details on the two error cases, I would not mind checking in
a merge of both our changes.
--
Joel