panic: kernel diagnostic assertion "pg->wire_count != 0" failed: file "/syzkaller/managers/netbsd-kubsan/kernel/sys/uvm

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: fd34b2d2 pmap_get_ptp(): the uvm_pagefree() call in the fa..
git tree: netbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=14c44649e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=824b23e1f4b6c76b
dashboard link: https://syzkaller.appspot.com/bug?extid=7b6763afbfe57930374f
compiler: g++ (Ubuntu 5.4.0-6ubuntu1~16.04.12) 5.4.0 20160609

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+7b6763...@syzkaller.appspotmail.com

[ 49.8515518] panic: kernel diagnostic
assertion "pg->wire_count != 0" failed:
file "/syzkaller/managers/netbsd-kubsan/kernel/sys/uvm/uvm_page.c", line
1582
[ 49.8666170] cpu0: Begin traceback...
[
49.9208680]
vpanic() at netbsd:vpanic+0x2aa sys/kern/subr_prf.c:336
[ 49.9809521] kern_assert() at netbsd:kern_assert+0x63
[
50.1413108]
uvm_pageunwire() at
netbsd:uvm_pageunwire+0x1e9
[
50.4516943]
uvm_fault_unwire_locked() at
netbsd:uvm_fault_unwire_locked+0x32d
[
50.7520557]
uvm_fault_unwire() at
netbsd:uvm_fault_unwire+0x31
[
50.8822409]
genfs_directio() at netbsd:genfs_directio+0xa1a
sys/miscfs/genfs/genfs_io.c:1749
[ 50.9323139] ffs_write() at netbsd:ffs_write+0xa7b
sys/ufs/ufs/ufs_readwrite.c:354
[ 50.9923991] VOP_WRITE() at netbsd:VOP_WRITE+0x108 sys/kern/vnode_if.c:506
[ 51.0524854] vn_write() at netbsd:vn_write+0x277 sys/kern/vfs_vnops.c:609
[ 51.1225873] do_filewritev.part.1() at netbsd:do_filewritev.part.1+0x415
[ 51.1826737] sys_writev() at netbsd:sys_writev+0x54 do_filewritev
sys/kern/sys_generic.c:381 [inline]
[ 51.1826737] sys_writev() at netbsd:sys_writev+0x54
sys/kern/sys_generic.c:381
[ 51.2327436] sys___syscall() at netbsd:sys___syscall+0x1c8 sy_call
sys/sys/syscallvar.h:65 [inline]
[ 51.2327436] sys___syscall() at netbsd:sys___syscall+0x1c8
sys/kern/sys_syscall.c:77
[ 51.2928321] syscall() at netbsd:syscall+0x29a sy_call
sys/sys/syscallvar.h:65 [inline]
[ 51.2928321] syscall() at netbsd:syscall+0x29a sy_invoke
sys/sys/syscallvar.h:94 [inline]
[ 51.2928321] syscall() at netbsd:syscall+0x29a
sys/arch/x86/x86/syscall.c:138
[ 51.3128601] --- syscall (number 198) ---
[ 51.3128601] Skipping crash dump on recursive panic
[ 51.3266278] panic: UBSan: Undefined Behavior in
/syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:153:24,
member access within misaligned address 0x3 for type 'struct x86_64_frame'
which requires 8 byte alignment

[ 51.3477253] Faulted in mid-traceback; aborting...
[ 51.3477253] fatal breakpoint trap in supervisor mode
[ 51.3557097] trap type 1 code 0 rip 0xffffffff8021e7cd cs 0x8 rflags
0x282 cr2 0x1b32a20000 ilevel 0 rsp 0xffff8000b2cd5bd0
[ 51.3685478] curlwp 0xffffab67c1e3c620 pid 472.3 lowest kstack
0xffff8000b2cd32c0
Stopped in pid 472.3 (syz-executor.1) at netbsd:breakpoint+0x5:
leave
?
breakpoint() at netbsd:breakpoint+0x5
db_panic() at netbsd:db_panic+0xd1 sys/ddb/db_panic.c:67
vpanic() at netbsd:vpanic+0x2aa sys/kern/subr_prf.c:336
isAlreadyReported() at netbsd:isAlreadyReported
HandleTypeMismatch.part.1() at netbsd:HandleTypeMismatch.part.1+0xcc
HandleTypeMismatch() at netbsd:HandleTypeMismatch+0x7b
sys/../common/lib/libc/misc/ubsan.c:408
db_nextframe() at netbsd:db_nextframe+0x6f6
sys/arch/amd64/amd64/db_machdep.c:153
db_stack_trace_print() at netbsd:db_stack_trace_print+0x2c4
sys/arch/x86/x86/db_trace.c:277
db_panic() at netbsd:db_panic+0x8b x86_curcpu
sys/arch/amd64/compile/obj/GENERIC_SYZKALLER/./machine/cpu.h:56 [inline]
db_panic() at netbsd:db_panic+0x8b sys/ddb/db_panic.c:57
vpanic() at netbsd:vpanic+0x2aa sys/kern/subr_prf.c:336
kern_assert() at netbsd:kern_assert+0x63
uvm_pageunwire() at netbsd:uvm_pageunwire+0x1e9 sys/uvm/uvm_page.c:1582
uvm_fault_unwire_locked() at netbsd:uvm_fault_unwire_locked+0x32d
sys/uvm/uvm_fault.c:2422
uvm_fault_unwire() at netbsd:uvm_fault_unwire+0x31 sys/uvm/uvm_fault.c:2388
genfs_directio() at netbsd:genfs_directio+0xa1a
sys/miscfs/genfs/genfs_io.c:1749
ffs_write() at netbsd:ffs_write+0xa7b sys/ufs/ufs/ufs_readwrite.c:354
VOP_WRITE() at netbsd:VOP_WRITE+0x108 sys/kern/vnode_if.c:506
vn_write() at netbsd:vn_write+0x277 sys/kern/vfs_vnops.c:609
do_filewritev.part.1() at netbsd:do_filewritev.part.1+0x415
sys_writev() at netbsd:sys_writev+0x54 do_filewritev
sys/kern/sys_generic.c:381 [inline]
sys_writev() at netbsd:sys_writev+0x54 sys/kern/sys_generic.c:381
sys___syscall() at netbsd:sys___syscall+0x1c8 sy_call
sys/sys/syscallvar.h:65 [inline]
sys___syscall() at netbsd:sys___syscall+0x1c8 sys/kern/sys_syscall.c:77
syscall() at netbsd:syscall+0x29a sy_call sys/sys/syscallvar.h:65 [inline]
syscall() at netbsd:syscall+0x29a sy_invoke sys/sys/syscallvar.h:94 [inline]
syscall() at netbsd:syscall+0x29a sys/arch/x86/x86/syscall.c:138
--- syscall (number 198) ---
[ 51.3759267] Skipping crash dump on recursive panic
[ 51.3759267] panic: UBSan: Undefined Behavior in
/syzkaller/managers/netbsd-kubsan/kernel/sys/arch/amd64/amd64/db_machdep.c:154:14,
member access within misaligned address 0x3 for type 'struct x86_64_frame'
which requires 8 byte alignment

[ 51.3759267] Faulted in mid-traceback; aborting...
[ 51.3759267] fatal breakpoint trap in supervisor mode
[ 51.3759267] trap type 1 code 0 rip 0xffffffff8021e7cd cs 0x8 rflags
0x282 cr2 0x1b32a20000 ilevel 0x8 rsp 0xffff8000b2cd48d0
[ 51.3759267] curlwp 0xffffab67c1e3c620 pid 472.3 lowest kstack
0xffff8000b2cd32c0
Stopped in pid 472.3 (syz-executor.1) at netbsd:breakpoint+0x5:
leave


---
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