Messages in this thread | | | Date | Sun, 5 Feb 2006 12:11:46 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH -mm] swsusp: freeze user space processes first |
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On Ne 05-02-06 11:50:37, Ingo Molnar wrote: > > * Rafael J. Wysocki <rjw@sisk.pl> wrote: > > > > The logic in that loop makes my brain burst. > > > > > > What happens if a process does vfork();sleep(100000000)? > > > > The freezing of processes will fail due to the timeout. > > > > Without the if (!p->vfork_done) it would fail too, because the child > > would be frozen and the parent would wait for the vfork completion in > > the TASK_UNINTERRUPTIBLE state (ie. unfreezeable). But in that case > > we have a race between the "freezer" and the child process (ie. if the > > child gets frozen before it completes the vfork completion, the paret > > will be unfreezeable) which sometimes leads to a failure when it > > should not. [We have a test case showing this.] > > then i'd suggest to change the vfork implementation to make this code > freezable. Nothing that userspace does should cause freezing to fail. > If it does, we've designed things incorrectly on the kernel side.
Does that also mean we have bugs with signal delivery? If vfork(); sleep(100000); causes process to be uninterruptible for few days, it will not be killable and increase load average... Pavel -- Thanks, Sharp! - 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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