On Tue, Dec 02, 2014 at 09:40:45PM +0300, Roman Gushchin wrote: > Hi, Tejun! > > 02.12.2014, 19:56, "Tejun Heo" <[email protected]>: > > Hello, Roman. > > > > On Fri, Nov 28, 2014 at 07:47:54PM +0300, Roman Gushchin wrote: > >> If cgroup_destroy_locked() sets the css refcount to a negative value, > >> we get an infinite loop in __css_tryget(). > >> > >> In this case css_refcnt() returns modified (non-negative value), so > >> both (t == v) and (t < 0) conditions are always false. > > > > I don't follow. The count is biased and modified by unbiasing iff the > > value is negative. Here, @v is the unbiased value and @t is the > > verbatim value. If @v is different from @t due to unbiasing, @t must > > be negative satisfying the second condition and returning NULL, no? > > Yep. I missed that we compare t with 0 (not v).
Hmm... what's up with the rcu stall message then? -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
