Re: kern/58531: NetBSD 10.0 deadlock in nd_timer

[gnats-admin%netbsd.org@localhost]

The following reply was made to PR kern/58531; it has been noted by GNATS.

From: Emmanuel Dreyfus <manu%netbsd.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/58531: NetBSD 10.0 deadlock in nd_timer
Date: Tue, 13 Aug 2024 00:52:09 +0000

 On Sun, Aug 11, 2024 at 04:25:01PM +0000, gnats-admin%netbsd.org@localhost wrote:
 >  We have a deadlock here:
 >  
 >  wm_handle_queue/wm_send_common_locked/bpf_deliver/selnotify/knote/filter_event waits for kernel_lock with txq->txq_lock held
 >  
 >  softint_dispatch/callout_softclock/nd_timer/arp_llinfo_output/arprequest/ether_output/if_transmit/wm_start waits for txq->txq_lock  with kernel_lock held.
 
 I do not see an easy way through this. Enabling NET_MPSAFE would remove
 kernel_lock here, but I use MROUTING, PIM, altq and ppp, which are
 known as MP-unsafe in src/doc/TODO.smpnet. 
 
 Is boot -1 the only workaround?
 
 -- 
 Emmanuel Dreyfus
 manu%netbsd.org@localhost