kernel panic: [kernel] Unknown mbox type ADDR!

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: bf9a9ba0d6af Add panic_hwtf() for kernel faults
git tree: https://github.com/akaros/akaros.git/master
console output: https://syzkaller.appspot.com/x/log.txt?x=10789578400000
kernel config: https://syzkaller.appspot.com/x/.config?x=efef8cf2939304d3
dashboard link: https://syzkaller.appspot.com/bug?extid=b388f4fce28bc1fdec70
compiler:

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b388f4...@syzkaller.appspotmail.com

kernel panic at kern/src/mm.c:737, from core 2: [kernel] Unknown mbox type
370929646!
assertion failed: !pte_is_mapped(pte)[kernel] Unknown mbox type 370929646!
Stack Backtrace on Core 2:
#01 [<0xffffffffc200a3e7>] in backtrace at src/kdebug.c:219
#02 [<0xffffffffc2009bb2>] in _panic at src/init.c:273
#03 [<0xffffffffc200dbd3>] in map_page_at_addr at src/mm.c:737
#04 [<0xffffffffc200dc22>] in populate_anon_va at src/mm.c:770
#05 [<0xffffffffc200fc92>] in populate_va at src/mm.c:1333
#06 [<0xffffffffc2056380>] in sys_populate_va at src/syscall.c:1773
#07 [<0xffffffffc20593c9>] in syscall at src/syscall.c:2528
#08 [<0xffffffffc2059584>] in run_local_syscall at src/syscall.c:2563
#09 [<0xffffffffc2059ab9>] in prep_syscalls at src/syscall.c:2583
#10 [<0xffffffffc20ab29a>] in sysenter_callwrapper at arch/x86/trap.c:851


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.