Messages in this thread | | | Date | Thu, 27 Mar 2014 00:40:38 +0100 | From | Daniel Borkmann <> | Subject | Re: [PATCH] random32: avoid attempt to late reseed if in the middle of seeding |
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On 03/27/2014 12:35 AM, Sasha Levin wrote: > On 03/26/2014 07:18 PM, Daniel Borkmann wrote: >> On 03/26/2014 06:12 PM, Sasha Levin wrote: >>> Commit 4af712e8df ("random32: add prandom_reseed_late() and call when >>> nonblocking pool becomes initialized") has added a late reseed stage >>> that happens as soon as the nonblocking pool is marked as initialized. >>> >>> This fails in the case that the nonblocking pool gets initialized >>> during __prandom_reseed()'s call to get_random_bytes(). In that case >>> we'd double back into __prandom_reseed() in an attempt to do a late >>> reseed - deadlocking on 'lock' early on in the boot process. >>> >>> Instead, just avoid even waiting to do a reseed if a reseed is already >>> occuring. >>> >>> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> >> >> Thanks for catching! (If you want Dave to pick it up, please also >> Cc netdev.) >> >> Why not via spin_trylock_irqsave() ? Thus, if we already hold the >> lock, we do not bother any longer with doing the same work twice >> and just return. > > Your code looks much better, I'll should really stop sending patches > too early in the morning... > > It's also worth adding lib/random32.c to the MAINTAINERS file, as my > list of recipients is solely based on what get_maintainer.pl tells > me to do (and I'm assuming that I'm not the last person who will be > sending patches for this).
Sounds like a good idea, afaik, historically, this got ripped out as a lib from networking subsystem. That's why we've sent it to netdev last time.
Cheers,
Daniel
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