Re: struct ifnet locking [was Re: IFEF_MPSAFE]

[Frank Kardel <kardel%netbsd.org@localhost>]

Hi,

does this panic (with -current/amd64 as of 20171221) ring a bell with 
anyone?

shortly after starting mrouted and ntpd:

panic: kernel diagnostic assertion "IFNET_LOCKED(ifp)" failed: file 
"/src/NetBSD/cur/src/sys/net/if.c", line 3602
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip 0xffffffff8021d2d5 cs 0x8 rflags 0x246 cr2 
0xffff80013dd84000 ilevel 0 rsp 0xffffe4013bb5aae0
curlwp 0xffffe404743f15c0 pid 916.1 lowest kstack 0xffffe4013bb572c0
Stopped in pid 916.1 (mrouted) at       netbsd:breakpoint+0x5: leave
db{3}> bt
breakpoint() at netbsd:breakpoint+0x5
vpanic() at netbsd:vpanic+0x140
ch_voltag_convert_in() at netbsd:ch_voltag_convert_in
if_mcast_op() at netbsd:if_mcast_op+0xb3
ip_mrouter_set() at netbsd:ip_mrouter_set+0xdef
rip_ctloutput() at netbsd:rip_ctloutput+0x11f
rip_ctloutput_wrapper() at netbsd:rip_ctloutput_wrapper+0x2c
sosetopt() at netbsd:sosetopt+0x67
sys_setsockopt() at netbsd:sys_setsockopt+0x91
syscall() at netbsd:syscall+0x235

Best regards,

  Frank


On 12/19/17 09:21, Ryota Ozaki wrote:
> On Tue, Dec 19, 2017 at 4:52 PM, Nick Hudson <nick.hudson%gmx.co.uk@localhost> wrote:
> > On 19/12/2017 03:43, Ryota Ozaki wrote:
> >
> >
> > > BTW I committed a change that disables IFEF_MPSAFE by default on
> > > all interfaces because it seems that IFEF_MPSAFE requires additional
> > > changes to work safely with it. We should enable it by default if an
> > > interface is guaranteed to be safe.
> > What additional changes?
> For example, avoid updating if_flags (and reading it and depending on
> the result) in Tx/Rx paths and using if_watchdog.
>
>    ozaki-r