From: Petr Sumbera <petr.sumbera@oracle.com>
To: Pedro Alves <palves@redhat.com>, gdb@sourceware.org
Subject: Re: Solaris - procfs: couldn't find pid 32748 (kernel thread 21) in procinfo list
Date: Wed, 3 Jun 2020 15:09:14 +0200 [thread overview]
Message-ID: <1c434ddf-8ce8-8206-e046-66b8dafc4a0d@oracle.com> (raw)
In-Reply-To: <7fdd8e25-ccd3-00eb-ae30-b9f8c7604fd8@redhat.com>
On 02.06.2020 19:14, Pedro Alves wrote:
> On 6/2/20 5:30 PM, Petr Sumbera wrote:
>
>> I have modified your change to gdb 9.2 and to correct occurrence (you have added it to second occurrence of 'exited'):
>>
>> --- ../../gdb-9.2/gdb/procfs.c.orig 2020-06-02 17:10:32.057735432 +0000
>> +++ ../../gdb-9.2/gdb/procfs.c 2020-06-02 18:02:45.496117117 +0000
>> @@ -2207,9 +2207,10 @@
>> if (print_thread_events)
>> printf_unfiltered (_("[%s exited]\n"),
>> target_pid_to_str (retval).c_str ());
>> - delete_thread (find_thread_ptid (retval));
>> - status->kind = TARGET_WAITKIND_SPURIOUS;
>> - return retval;
>> + thread_info *thr = find_thread_ptid (retval);
>> + if (thr)
>> + delete_thread (thr);
>> + goto wait_again;
>> }
>> else if (syscall_is_exit (pi, what))
>> {
>>
>> But this time exited message repeats forever:
>>
>> [LWP 24 exited]
>> [LWP 24 exited]
>> [LWP 24 exited]
>
> Sounds like the LWP is stuck with the status, or the status is
> cached. We probably need to resume the process to move it out
> of the syscall, I guess. There's this bit in the file, at
> another spot we call goto wait_again:
>
> /* How to keep going without returning to wfi: */
> target_continue_no_signal (ptid);
> goto wait_again;
>
> wfi == wait_for_inferior, the name of a function that used
> to be pretty core in infrun.c. Nowadays handle_inferior_event
> took the role.
>
> Try doing the same. Like:
>
> delete_thread (find_thread_ptid (this, retval));
> target_continue_no_signal (ptid);
> goto wait_again;
>
> You may need to split the delete_thread/find_thread bits, or
> you may not. I'm not sure.
>
> The TARGET_WAITKIND_SPURIOUS handling in infrun.c also
> just calls resume(GDB_SIGNAL_0), so I _think_ this will work as
> well as before. I have no idea how this was supposed to handle
> the case of an LWP exiting while another one is single
> stepping. Looks like we lose the original single-stepping
> request. Maybe. Not sure. But doesn't look like we're
> making things any worse.
This time it looks very promising. This is gdb 9.2 patch:
--- gdb-9.2/gdb/procfs.c
+++ gdb-9.2/gdb/procfs.c
@@ -2208,8 +2208,8 @@
printf_unfiltered (_("[%s exited]\n"),
target_pid_to_str
(retval).c_str ());
delete_thread (find_thread_ptid (retval));
- status->kind = TARGET_WAITKIND_SPURIOUS;
- return retval;
+ target_continue_no_signal (ptid);
+ goto wait_again;
}
else if (syscall_is_exit (pi, what))
{
This works for few test cases. And I actually started gdb tests to see
if it makes any regression (but it might take some time to run it though).
But in one particular case it returns following:
..
[LWP 33 exited1]
[LWP 31 exited1]
[LWP 32 exited1]
[LWP 28 exited1]
[LWP 30 exited1]
[LWP 2 exited1]
sol_thread_fetch_registers: td_ta_map_id2thr: no thread can be found to
satisfy query
sol_thread_fetch_registers: td_ta_map_id2thr: no thread can be found to
satisfy query
(gdb)
It might be related...
Thank you very much!
Petr
next prev parent reply other threads:[~2020-06-03 13:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 15:29 Petr Sumbera
2020-05-28 16:01 ` Rainer Orth
2020-06-01 12:47 ` Petr Sumbera
2020-06-01 11:39 ` Petr Sumbera
2020-06-01 19:12 ` Pedro Alves
2020-06-02 7:32 ` Petr Sumbera
2020-06-02 14:53 ` Pedro Alves
2020-06-02 16:30 ` Petr Sumbera
2020-06-02 17:14 ` Pedro Alves
2020-06-03 13:09 ` Petr Sumbera [this message]
2020-06-08 9:51 ` Petr Sumbera
2020-06-08 13:47 ` Pedro Alves
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