Messages in this thread |  | | | Date | Mon, 7 Nov 2011 21:31:31 +0800 | | From | Yong Zhang <> | | Subject | Re: [PATCH 1/4] lockdep: lock_set_subclass() fix |
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On Mon, Nov 07, 2011 at 01:34:39PM +0100, Peter Zijlstra wrote: > On Fri, 2011-11-04 at 17:26 +0800, Yong Zhang wrote: > > Since commit f59de89 [lockdep: Clear whole lockdep_map on initialization], > > lockdep_init_map() will clear all the struct. But it will break > > lock_set_class()/lock_set_subclass(). A typical race condition > > is like below: > > This is a horridly ugly patch, why not simply revert that memset commit?
I prefer reverting that commit, but bugzilla is down and I don't know what the real problem behind that commit.
> I really can't see the point of that, and keeping the name/key pointers > around (which can only be over-written with the same values, right?) > would also cure the problem. > > Sadly the changelog is completely devoid of useful information (which is > my own damn fault, I should never have accepted the patch in that form), > so I can't actually comment on what it was supposed to fix.
me too :( And going through lkml history, I find nothing about it.
> > Arguably kmemcheck is on crack or so since both name and key pointers > should be in .data so there cannot be a leak by copying the thing over.
Maybe Tejun can give more detail on it.
Thanks, Yong
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