Messages in this thread | | | Date | Wed, 8 Dec 2004 20:55:32 -0800 | From | Matt Mackall <> | Subject | Re: Concurrent access to /dev/urandom |
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On Thu, Dec 09, 2004 at 10:46:30AM +0800, andyliu wrote: > hi Ted > > i think this is better than use the spin lock. > but i think maybe there should put an #ifdef SMP :) > just like > > #ifdef CONFIG_SMP > tmp[0] = 0x67452301 ^ smp_processor_id(); > tmp[1] = 0xefcdab89 ^ (__u32) current; > tmp[2] = 0x98badcfe ^ preempt_count(); > #endif > > is it needed?
The race can be hit with get_random_bytes on UP if we get interrupted/preempted between hashing and mixing. Which is why preempt_count is useful..
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