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Re: [PATCH 3/N] remote follow fork and spurious child stops in non-stop mode
- From: Pedro Alves <palves at redhat dot com>
- To: Don Breazeal <donb at codesourcery dot com>, "Breazeal, Don" <Don_Breazeal at mentor dot com>, Simon Marchi <simon dot marchi at ericsson dot com>
- Cc: GDB Patches <gdb-patches at sourceware dot org>
- Date: Wed, 29 Jul 2015 17:40:43 +0100
- Subject: Re: [PATCH 3/N] remote follow fork and spurious child stops in non-stop mode
- Authentication-results: sourceware.org; auth=none
- References: <1437672294-29351-1-git-send-email-palves at redhat dot com> <55B1308E dot 4020700 at redhat dot com> <55B2875E dot 1070504 at codesourcery dot com> <55B8D34F dot 5060002 at redhat dot com> <55B8D765 dot 9010003 at redhat dot com> <55B8E1C4 dot 9080605 at redhat dot com> <55B8F3FC dot 9010108 at redhat dot com>
On 07/29/2015 04:40 PM, Pedro Alves wrote:
> On 07/29/2015 03:23 PM, Pedro Alves wrote:
>> On 07/29/2015 02:38 PM, Pedro Alves wrote:
>>
>>> Ignore the "SIGTRAP" mention in "SEL: Found 2 SIGTRAP events",
>>> it's "two events". And the one that was picked was a process
>>> exit. But the tail end of linux_wait_1 isn't expecting that
>>> can happen.
>>>
>>
>> This seems to fix it (and ends up making the code a little
>> more like linux-nat.c). I'm running it through the testsuite.
>
> It passes cleanly.
>
> And I confirmed that that test idea triggers the suspend count
> assertion I suspected:
>
> Child exited with status 0
> /home/pedro/gdb/mygit/build/../src/gdb/gdbserver/linux-low.c:2619: A problem internal to GDBserver has been detected.
> unsuspend_one_lwp: Assertion `lwp->suspended >= 0' failed.
> [Inferior 1 (process 32473) exited with code 01]
> (gdb)
>
> I'll convert that to a proper test.
>
And that that exposes more issues, like:
[New Thread 27183.27382]
[New Thread 27183.27684]
/home/pedro/gdb/mygit/build/../src/gdb/thread.c:936: internal-error: finish_thread_state: Assertion `tp' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.threads/fork-plus-threads-2.exp: inferior 1 exited (GDB internal error)
Resyncing due to internal error.
n
...
Detaching from process 28486
Detaching from process 28487
Detaching from process 28488
/home/pedro/gdb/mygit/build/../src/gdb/gdbserver/linux-low.c:3569: A problem internal to GDBserver has been detected.
stuck_in_jump_pad_callback: Assertion `lwp->suspended == 0' failed.
testcase /home/pedro/gdb/mygit/build/../src/gdb/testsuite/gdb.threads/fork-plus-threads-2.exp completed in 3 seconds
=== gdb Summary ===
Looks like I found myself a nice deep rat hole...
Thanks,
Pedro Alves