Messages in this thread Patch in this message | | | Date | Fri, 3 Aug 2007 01:37:30 +0400 | From | Oleg Nesterov <> | Subject | [PATCH, RESEND] pi-futex: set PF_EXITING without taking ->pi_lock |
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It is a bit annoying that do_exit() takes ->pi_lock to set PF_EXITING. All we need is to synchronize with lookup_pi_state() which saw this task without PF_EXITING under ->pi_lock.
Change do_exit() to use spin_unlock_wait().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Ingo Molnar <mingo@elte.hu>
--- t/kernel/exit.c~PF_EXIT 2007-06-19 17:09:15.000000000 +0400 +++ t/kernel/exit.c 2007-07-21 15:34:13.000000000 +0400 @@ -908,13 +908,13 @@ fastcall NORET_TYPE void do_exit(long co schedule(); } + tsk->flags |= PF_EXITING; /* * tsk->flags are checked in the futex code to protect against * an exiting task cleaning up the robust pi futexes. */ - spin_lock_irq(&tsk->pi_lock); - tsk->flags |= PF_EXITING; - spin_unlock_irq(&tsk->pi_lock); + smp_mb(); + spin_unlock_wait(&tsk->pi_lock); if (unlikely(in_atomic())) printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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