Re: GDB locks up -- Cannot find new threads: generic error

Andreas Schwab
2005-04-27T22:46:48Z

Daniel Jacobowitz <drow@false.org> writes:

> On Wed, Apr 27, 2005 at 07:42:37PM +0100, David Lecomber wrote:
>> (gdb) b main
>> Breakpoint 1 at 0x804ed18: file
>> main.cpp, line 10.
>> (gdb) run
>> Starting program: a.out
>> warning: linux_test_for_tracefork: unexpected result from waitpid
>> (28261,
>> status 0x117f)
>> [Thread debugging using libthread_db enabled]
>> Error while reading shared library symbols:
>> Cannot find new threads: generic error
>>
>> at this point GDB does nothing and is unresponsive to any user input.
>>
>> The system is:
>> kernel-2.4.21-27.EL
>> glibc-2.3.2-95.30
>
> At a guess, your kernel is buggered. You really should never see that
> warning. The unexpected signal is SIGCHLD; your kernel has accepted
> the SETOPTIONS but obviously failed to stop when the test thread
> vforked.

I think that can happen when the 32 bit ptrace emulation is incomplete,
especially if PTRACE_GETEVENTMSG is not properly emulated. That should be
fixed in recent (< 9 months) kernels.

Andreas.

--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, MaxfeldstraÃŸe 5, 90409 NÃ¼rnberg, Germany
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