SIGILL @ pthread_create() after execv -FIXED-

David Xu davidxu at freebsd.org
Thu Sep 16 15:46:13 PDT 2004


Julian Elischer wrote:

> Ick.
>
>
> Joost Bekkers wrote:
>
>> On Thu, Sep 16, 2004 at 06:28:28PM +0200, Joost Bekkers wrote:
>>  
>>
>>> On Thu, Sep 16, 2004 at 12:38:56AM -0700, Julian Elischer wrote:
>>>   
>>>
>>>> I checked in David's patch, which may fox this..
>>>> try -current .
>>>>
>>>>     
>>>
>>> I'm not experiencing the problem anymore.
>>>
>>>   
>>
>>
>> Celebrated too soon....
>>
>> Signals are not being delivered to the process after it did
>> its execv.
>>
>> The only signal that seems to be working is KILL (-9)
>>
>
> the man page is:  (for execve)
>     Signals set to be ignored in the calling process are set to be 
> ignored in
>     the new process.  Signals which are set to be caught in the calling
>     process image are set to default action in the new process image.
>     Blocked signals remain blocked regardless of changes to the signal
>     action.  The signal stack is reset to be undefined (see 
> sigaction(2) for
>     more information).
>
> so we need to keep track of all signals accepted by the process (which 
> is an
> OR of the signals accepted by all the threads) and set it back to that 
> state
> regardless of what thread is doing the exit.
> (yuck that is quite a difficult question)  I wonder if the "signal 
> gatherring thread"
> has that info?
>
> Maybe if the signal thread exits  it should look to see if the process 
> is exec/exiting
> (by looking at the thread_single mode) and transfer its mask to teh 
> 'survicor' thread?
>
> David?
>
I think this becauses the M:N thread masks all signals except SIGSTOP 
and SIGKILL,
the real signal mask in userland needs to be set back to kernel, 
libpthread should
provide a wrapper for execv syscall, Dan?  fix me if I am wrong.

Posix says:

The initial thread of the new process shall inherit at least the 
following attributes
from the calling thread:

    *

      Signal mask (see /sigprocmask/()
      <http://www.opengroup.org/onlinepubs/009695399/functions/sigprocmask.html>
      and /pthread_sigmask/()
      <http://www.opengroup.org/onlinepubs/009695399/functions/pthread_sigmask.html>)

    *

      Pending signals (see /sigpending/()
      <http://www.opengroup.org/onlinepubs/009695399/functions/sigpending.html>)

    *





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