This is the mail archive of the gdb@sourceware.org mailing list for the GDB project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [bug?] [patch] target remote and multiprocess+


Hi,

On 11/23/2016 02:55 AM, Matthias Pfaller wrote:
To make sure I'm not totally wrong I did run an (unpatched) gdbserver
(7.11.1) -multi on my host machine. Then I connected with
extended-remote and created two inferiors. After a disconnect and a
reconnect gdbserver responds with the following inferior/thread list:

l<threads>\n<thread id="p29ae.29ae" core="3" name="xterm"/>\n<thread
id="p3dcf.3dcf" core="1" name="xterm"/>\n</threads>\n

But doing a "info inferiors" will show:
(gdb) info inferiors
  Num  Description       Executable
* 1    process 15823     /usr/uti/xterm

and info threads:
(gdb) info threads
Sending packet: $qXfer:threads:read::0,fff#03...Packet received:
l<threads>\n<thread id="p29ae.29ae" core="3" name="xterm"/>\n<thread
id="p3dcf.3dcf" core="1" name="xterm"/>\n</threads>\n
  Id   Target Id         Frame
  1    Thread 10670.10670 "xterm"
../../gdb/thread.c:1447: internal-error: switch_to_thread: Assertion
`inf != NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)

(note that this is the host system's gdb 7.11.1)
So attaching to a target with multiple running inferiors just doesn't
work at the moment.

Now I tried with gdb-7.12 and my patches applied:

(gdb) set non-stop on
(gdb) target remote localhost:29979
Remote debugging using localhost:29979
Reading /usr/uti/xterm from remote target...
warning: File transfers from remote targets can be slow. Use "set
sysroot" to access files locally instead.
Reading /usr/uti/xterm from remote target...
Reading symbols from target:/usr/uti/xterm...(no debugging symbols
found)...done.
Python Exception <type 'exceptions.NameError'> Installation error:
gdb.execute_unwinders function is missing:

Thread 1.1 "xterm" stopped.
0x00007ffff7ddac80 in ?? ()
Python Exception <type 'exceptions.NameError'> Installation error:
gdb.execute_unwinders function is missing:

Thread 2.1 "xterm" stopped.
0x00007ffff7ddac80 in ?? ()
(gdb) info threads
  Id   Target Id         Frame
  1.1  Thread 10670.10670 "xterm" Python Exception <type
'exceptions.NameError'> Installation error: gdb.execute_unwinders
function is missing:
0x00007ffff7ddac80 in ?? ()
* 2.1  Thread 15823.15823 "xterm" Python Exception <type
'exceptions.NameError'> Installation error: gdb.execute_unwinders
function is missing:
0x00007ffff7ddac80 in ?? ()
(gdb) info inferiors
  Num  Description       Executable
  1    process 10670     target:/usr/uti/xterm
* 2    process 15823     target:/usr/uti/xterm

So I think this is at least not worse than what gdb was doing before...
Is there a chance to get this patch into gdb?

Matthias


I think i misunderstood your initial explanation. So the patch in questions attempts to fix the internal error plus the fact that GDB doesn't show more than one inferior when connecting to a gdbserver that is controlling multiple inferiors?

If so, indeed it is a bug and i still see it on master GDB. I'd send the patch to gdb-patches so we can properly review it.

Also, did you run the gdb testsuite to make sure your patch did not introduce regressions comparing against the unpatch gdb testsuite run?

You can run the testsuite like this:

make check-gdb (top-level) or make-gdb

You should also run the testsuite against gdbserver like this:

make check-gdb RUNTESTFLAGS="--target_board native-gdbserver"


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]