Re: kern/50186: sparc memfault panic after 7.99.21 ARP changes

[christos%zoulas.com@localhost (Christos Zoulas)]

On Sep 4,  6:10pm, ozaki-r%netbsd.org@localhost (Ryota Ozaki) wrote:
-- Subject: Re: kern/50186: sparc memfault panic after 7.99.21 ARP changes

| On Fri, Sep 4, 2015 at 5:40 PM, Christos Zoulas <christos%zoulas.com@localhost> wrote:
| > On Sep 4,  1:50pm, ozaki-r%netbsd.org@localhost (Ryota Ozaki) wrote:
| > -- Subject: Re: kern/50186: sparc memfault panic after 7.99.21 ARP changes
| >
| > | On Thu, Sep 3, 2015 at 8:38 PM, Christos Zoulas <christos%zoulas.com@localhost> wrote:
| > | > I just crashed in arptimer() so there are more locking problems in the code. Can you document the locking discipline for la_rt and changing the lists?
| > | >
| > |
| > | I'm sorry for the defect.
| > |
| > | An ARP cache list of an interface is protected by a rwlock
| > | (IF_AFDATA_*LOCK) and each ARP cache is protected by a rwlock
| > | and refernce counting (LLE_*LOCK). However, la_rt still needs
| > | softnet_lock; if la_rt is accessed or modified without
| > | softnet_lock, it's a bug. And I found a bug :( lltable_free
| > | accesses la_rt but it's called without softnet_lock.
| > |
| > | Here is a patch:
| > | http://www.netbsd.org/~ozaki-r/lltable_free-softnet_lock.diff
| > | Could you try it?
| > |
| >
| > Thanks, I am running with it now. Should we revert the KASSERT change
| > too?
| 
| Well, yes and no. Because KASSERT was actually wrong; la_rt can be NULL
| at the point according to my investigation for PR 50184. So anyway we
| have to get rid of it.
| 
| I made a patch for the bug:
| http://www.netbsd.org/~ozaki-r/fix-PR50184.take2.diff
| which was for PR 50184. So reverting your commit and applying the patch
| instead might be easy for me. Of course rebasing my patch on the HEAD
| makes no difference though.

Why don't you commit both of them?

christos