assertion failed: BHLEN(bp) >= offsetof(struct etherpkt, data)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 9196d29ad275 qio: Fix Qmsg panic in read_all_blocks()
git tree: https://github.com/akaros/akaros.git/master
console output: https://syzkaller.appspot.com/x/log.txt?x=1136b51c400000
kernel config: https://syzkaller.appspot.com/x/.config?x=efef8cf2939304d3
dashboard link: https://syzkaller.appspot.com/bug?extid=3d8007cb48c458a19837
compiler:
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=10e24d62400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=163da978400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3d8007...@syzkaller.appspotmail.com

kernel panic at kern/drivers/dev/ether.c:317, from core 0: assertion
failed: BHLEN(bp) >= offsetof(struct etherpkt, data)
Stack Backtrace on Core 0:
#01 [<0xffffffffc200a2bc>] in backtrace at src/kdebug.c:220
#02 [<0xffffffffc2009afd>] in _panic at src/init.c:268
#03 [<0xffffffffc2077b63>] in etheriq at drivers/dev/ether.c:317
#04 [<0xffffffffc2077d2e>] in etheroq at drivers/dev/ether.c:424
#05 [<0xffffffffc2077faf>] in etherwrite at drivers/dev/ether.c:505
#06 [<0xffffffffc2040221>] in rwrite at src/ns/sysfile.c:1123
#07 [<0xffffffffc204043b>] in syswrite at src/ns/sysfile.c:1141
#08 [<0xffffffffc2055f61>] in sys_write at src/syscall.c:1785
#09 [<0xffffffffc2059439>] in syscall at src/syscall.c:2528
#10 [<0xffffffffc2059604>] in run_local_syscall at src/syscall.c:2563
#11 [<0xffffffffc2059b39>] in prep_syscalls at src/syscall.c:2583
#12 [<0xffffffffc20ab38a>] in sysenter_callwrapper at arch/x86/trap.c:854


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