Public bug reported: == SRU [Eoan] ==
The 8 bit pseudo-random number generator mwc8() is being zero'd whenever a 1 bit value from mwc1() is generated. This causes mwc8() to generate a stream of 1 to 31 zeros until all the bits are shifted out of a 32 bit entropy state and the next 8 bit value is generated. == Fix == Upstream fix (in Focal): commit 99e65ccceedc12e68e34dc1ceb51ae0d5f3787ff Author: Colin Ian King <colin.k...@canonical.com> Date: Fri Nov 29 10:55:42 2019 +0000 core-mwc: fix mwc8() being reset when using mwc1() == Test == This cannot be easily regression tested, one has to attach a debugger to observe mwc1() clobbering the mwc8() internal state. == Regression Potential == Since this fixes the random number generation when mwc1() is called, it changes the random behaviour of various stressors that use mwc1() and mwc8() together. This affects the following stressors: mmapfixed, sock and swap. The changes now make the stressors behave more randomly and hence this may affect the way a system is being stressed. ** Affects: stress-ng (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1855851 Title: stress-ng mwc8() getting reset when mwc1() is called To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/stress-ng/+bug/1855851/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs