In message <[email protected]>, Hal Mu rray writes:
>>From Steven Bellovin, on NANOG: > See > http://landslidecoding.blogspot.com/2012/07/linuxs-leap-second-deadlocks.html Interesting. When we started out adding SMP support to FreeBSD, the first thing we did was to import BSDI's "Witness" subsystem, which is a runtime facility that keeps track of and warns about lock-order reversals. If you accidentally introduce a lock-order reversal, witness will detect it at runtime and tell you, even if you didn't hit the deadlock this time. If Linux had taken our, many times repeated, advice and imported Witness they would at least have avoided bug 1, 2 & 3. >The 4th bug explains the CPU load spikes. A kernel bug broke futex-es. They >are typically used in spin-lock like loops from user code. Not really "spin-locks", I belive it is the kernel the basis for the pthread mutex in Linux. >The 5th bug is still a mystery. No, not really: It's because time doesn't advance a full second for a full seconds. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [email protected] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
