Re: [PATCH 2/2] kthread_worker: reimplement flush_kthread_work() to allow freeing the work item being executed

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello,

On Sun, Jul 22, 2012 at 04:46:54PM -0400, Andy Walls wrote:
> Hmmm, I didn't know about the constraint about 'known to be alive' in
> the other email I just sent.
> 
> That might make calling flush_kthread_work() hard for a user to use, if
> the user lets the work get freed by another thread executing the work.

Umm... flushing a freed work item doesn't make any sense at all.  The
pointer itself loses the ability to identify anything.  What if it
gets recycled to another work item which happens to depend on the
flusher to make forward progress?  You now have a circular dependency
through a recycled memory area.  Good luck hunting that down.

For pretty much any API, allowing dangling pointers as argument is
insane.  If you want to flush self-freeing work items, flush the
kthread_worker.  That's how it is with workqueue and how it should be
with kthread_worker too.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux