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Groups > linux.kernel > #1192915
| From | Oliver Neukum <oneukum@suse.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: Several races in "usbnet" module (kernel 4.1.x) |
| Date | 2015-07-27 12:10 +0200 |
| Message-ID | <pQNw6-6QN-3@gated-at.bofh.it> (permalink) |
| References | <pOnZ8-Kj-31@gated-at.bofh.it> <pOGIq-2tt-7@gated-at.bofh.it> <pP75U-7Hu-1@gated-at.bofh.it> <pPkPv-2nG-9@gated-at.bofh.it> <pPMsp-iu-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, 2015-07-24 at 17:41 +0300, Eugene Shatokhin wrote: > 23.07.2015 12:15, Oliver Neukum пишет: > From what I see now in Documentation/atomic_ops.txt, stores to the > properly aligned memory locations are in fact atomic. They are, but again only with respect to each other. > So, I think, the situation you described above cannot happen for > dev->flags, which is good. No need to address that in the patch. The > race might be harmless after all. > > If I understand the code correctly now, dev->flags is set to 0 in > usbnet_stop() so that the worker function (usbnet_deferred_kevent) would Yes, particularly not reschedule itself. > do nothing, should it start later. If so, how about adding memory > barriers for all CPUs to see dev->flags is 0 before other things? Taking a lock, as del_timer_sync() does, implies a memory barrier, as does a work. Regards Oliver -- 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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Re: Several races in "usbnet" module (kernel 4.1.x) Oliver Neukum <oneukum@suse.com> - 2015-07-27 12:10 +0200 Re: Several races in "usbnet" module (kernel 4.1.x) Eugene Shatokhin <eugene.shatokhin@rosalab.ru> - 2015-07-27 16:30 +0200
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