Re: [LKP] [percpu] BUG: unable to handle kernel NULL pointer dereference at (null)
On Tue, Sep 02, 2014 at 11:00:12AM -0500, Christoph Lameter wrote:
On Tue, 2 Sep 2014, Paul E. McKenney wrote:
> Before this commit, raw_cpu_add_return() didn't build. The commit
> didn't affect anything else.
>
> So I don't understand how anything could work before this commit and
> be broken after it. Enlightenment?
Where is that raw_cpu_add_return statement?
grep does not match anything like that in kernel/rcu/*
and this_cpu_add_return is used extensively in the network subsystem for
statistics.
Heh! Good point!
Added by ac1bea85781e (sched,rcu: Make cond_resched() report RCU quiescent
states), removed by 4a81e8328d379 (rcu: Reduce overhead of cond_resched()
checks for RCU). So, as you say, no effect on contemporary kernels.
Thanx, Paul