Messages in this thread |  | | | Date | Fri, 30 Apr 2010 11:33:34 -0400 | | From | Mathieu Desnoyers <> | | Subject | Re: [PATCH tip/core/urgent] fix several lockdep splats, allow multiple splats |
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* Ingo Molnar (mingo@elte.hu) wrote: > > * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote: > > > Hello! > > > > This patchset contains four RCU lockdep splat fixes, courtesy of David > > Howells, Peter Zijlstra, and Trond Myklebust, [...] > > I've applied #1 and #2 - but shouldnt #4 and #5 go via the NFS tree? > > > [...] as well as an enhancement by Lai Jiangshan that permits collecting > > more than one RCU lockdep splat per boot. > > Hm, this #3 patch i disagree with quite fundamentally: one of the big virtues > of lockdep is that it complains only once and then shuts up and lets the > system work. It allows distro debug kernels to have lockdep enabled, etc. > > One bugreport per bootup per user is the most we can expect really. Not > disabling it risks getting a stream of repeat messages, annoyed testers and > gives us _less_ bugreports in the end. > > Also, often the _first_ warning is the most reliable one - sometimes there's > interactions, and the first bug causing a second warning as well, etc. So > reporting just the highest-quality (i.e. first) issue we detect is the best > approach.
I recommend creating a kernel command line parameter that would tweak the number of messages printed by lockdep. The default would indeed by 1 message, but people in a debugging marathon can specify a larger value so they won't have to reboot between each individual lockdep error.
Thanks,
Mathieu
> > Thanks, > > Ingo
-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
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