Re: [PATCH v4 4/6] hw_random: fix unregister race.

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

 



On Mon, Nov 10, 2014 at 09:47:27PM +0800, Herbert Xu wrote:
> On Mon, Nov 03, 2014 at 11:56:24PM +0800, Amos Kong wrote:
> >
> > @@ -98,6 +99,8 @@ static inline void cleanup_rng(struct kref *kref)
> >  
> >  	if (rng->cleanup)
> >  		rng->cleanup(rng);
> 
> You need a compiler barrier here to prevent reordering.

Michael Büsch pointed out that we should actually have a memory
barrier here.  I thought we didn't need it because I was only
worried about the code in my original complaint.  However, expecting
driver writers to use correct synchronisation primitives is surely
asking too much.

So let's add an smp_wmb() here to ensure all side-effects of
cleanup is visible.

Thanks,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization





[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux