#12164 NORM 13.1.0: XO-4 os5 yum Invalid GPG Key
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bugtracker at laptop.org
Fri Nov 9 19:27:10 EST 2012
#12164: XO-4 os5 yum Invalid GPG Key
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Reporter: Quozl | Owner: dsd
Type: defect | Status: new
Priority: normal | Milestone: 13.1.0
Component: distro | Version: not specified
Resolution: | Keywords:
Next_action: never set | Verified: 0
Deployment_affected: | Blockedby:
Blocking: |
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Comment(by wmb at firmworks.com):
I've done a fair amount of exploration of this program too, and have seen
some bizarre results. For example, if you insert the line
{{{
foo = crc & 0x1000000
}}}
before the if statement, the answer changes. Worse yet, the answer
sometimes changes from run to run of the same program text!
I have looked at the implementation of the Python interpreter to see what
happens when you say "if crc & 0x1000000 :". It turns out to be
surprisingly complex, due to the fact that Python internally represents
long integer values in sign-magnitude format, converting to twos-
complement for bitwise operations, and then back to sign-magnitude for the
result. Furthermore, the interpretation of an integer value as a boolean
(i.e. for "if") depends on a size optimization where a zero-valued integer
is represented as an object of size 0. All of this results in allocation
of new temporary objects, so there are many opportunities for memory or
cache corruption to change values.
This one has me worried...
--
Ticket URL: <http://dev.laptop.org/ticket/12164#comment:10>
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