Messages in this thread | | | Date | Sun, 21 Aug 2005 14:41:50 +0400 | From | Oleg Nesterov <> | Subject | Re: [PATCH] fix send_sigqueue() vs thread exit race |
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Thomas Gleixner wrote: > > On Sat, 2005-08-20 at 20:58 +0400, Oleg Nesterov wrote: > > [PATCH] fix send_sigqueue() vs thread exit race > > > > ..... > > - read_lock(&tasklist_lock); > > + read_lock(&tasklist_lock); > > + > > + if (unlikely(p->flags & PF_EXITING)) { > > + ret = -1; > > + goto out_err; > > + } > > + > > It's still racy. tasklist_lock does not protect anything here.
I hope no, but please clarify if I am wrong.
tasklist_lock protects against release_task()->__exit_sigxxx() here.
> arm timer > exit
If this is the last thread in thread group, exit_itimers() will stop and clear ->posix_timers.
If not:
> timer event > timr->it_process references a freed structure >
No, create_timer() does get_task_struct(timr->it_process), this task may be EXIT_DEAD now, but the task_struct itself is valid, and it's ->flags has PF_EXITING flag.
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