kern/48813: Use of ppp interface causes kernel panic

[dogan%tesmer.org.tr@localhost]

>Number:         48813
>Category:       kern
>Synopsis:       Use of ppp interface causes kernel panic
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat May 17 04:05:00 +0000 2014
>Originator:     Mustafa Dogan
>Release:        NetBSD 6.99.41
>Organization:
www.tesmer.org.tr
>Environment:
NetBSD md.dogan.biz.tr 6.99.41 NetBSD 6.99.41 (GENERIC) #0: Thu May 16 05:47:43 
EEST 2014  
root%md.dogan.biz.tr@localhost:/root/OBJ/sys/arch/amd64/compile/GENERIC amd64
>Description:
After src/sys/net changes dated 2014/05/15, use of ppp interface causes kernel 
panic.
I updated -current source tree and and made release with build.sh on 
2014/05/16. 

# cd /usr/src; ./build.sh -x release

Then, I installed new kernel and userland. Now, when I try to use ppp 
interface, it causes kernel panic.

# pppd call 3g.ppp
# nslookup www.netbsd.org

At this point, kernel panicking.

panic: kernel diagnostic assertion "offset != 0 && offset < softint_bytes" 
failed: file "/usr/src/sys/kern/kern_softint.c", line 467 0 8192
cpu0: Begin traceback...
vpanic() at netbsd:vpanic+0x13c
kern_assert() at netbsd:kern_assert+0x4f
softint_schedule() at netbsd:softint_schedule+0x77
pppintr() at netbsd:pppintr+0x2ed
softint_dispatch() at netbsd:softint_dispatch+0xd3
DDB lost frame for netbsd:Xsoftintr+0x4f, trying 0xfffffe80068a5ff0
Xsoftintr() at netbsd:Xsoftintr+0x4f
--- Interrupt ---
0:
cpu0: End traceback

>How-To-Repeat:
Build new kernel with -current source dated 2014/05/16 and reboot with it. Then 
use ppp interface (for example a 3G modem with ppp interface).
>Fix:
Probably this problem occurred after the src/sys/net source changes at 
2014/05/15 related to schednetisr().