Bad page state in metha-sync (arm)

[miku]

Debian 10 on arm.

...
[85698.893018] BUG: Bad page state in process metha-sync  pfn:000f0
[85698.899047] page:eedfa1c0 count:0 mapcount:0 mapping:00000000 index:0x1
[85698.905676] flags: 0x400(arch_1)
[85698.908913] raw: 00000400 00000100 00000200 00000000 00000001 00000000 ffffffff 00000000
[85698.917021] raw: 00000000
[85698.919644] page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
[85698.925836] bad because of flags: 0x400(arch_1)
[85698.930374] Modules linked in: tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag nf_tables nfnetlink softdog overlay zstd zram zsmalloc orion_wdt pwm_fan nfsd lm75 marvell_cesa ip_tables x_tables raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 md_mod
[85698.930421] CPU: 1 PID: 31563 Comm: metha-sync Not tainted 4.19.63-mvebu #5.91
[85698.930423] Hardware name: Marvell Armada 380/385 (Device Tree)
[85698.930438] [<c010ce11>] (unwind_backtrace) from [<c01095eb>] (show_stack+0xb/0xc)
[85698.930446] [<c01095eb>] (show_stack) from [<c0706b25>] (dump_stack+0x69/0x78)
[85698.930453] [<c0706b25>] (dump_stack) from [<c01ac8e1>] (bad_page+0xa5/0xe4)
[85698.930460] [<c01ac8e1>] (bad_page) from [<c01ae94b>] (get_page_from_freelist+0x757/0xad4)
[85698.930465] [<c01ae94b>] (get_page_from_freelist) from [<c01af22d>] (__alloc_pages_nodemask+0xc5/0xa20)
[85698.930473] [<c01af22d>] (__alloc_pages_nodemask) from [<c01cb9e1>] (handle_mm_fault+0x42d/0x980)
[85698.930479] [<c01cb9e1>] (handle_mm_fault) from [<c01100db>] (do_page_fault+0xd3/0x22c)
[85698.930484] [<c01100db>] (do_page_fault) from [<c011034d>] (do_DataAbort+0x3d/0xa8)
[85698.930489] [<c011034d>] (do_DataAbort) from [<c0101dcf>] (__dabt_usr+0x4f/0x60)
[85698.930491] Exception stack(0xedd7ffb0 to 0xedd7fff8)
[85698.930495] ffa0:                                     00000000 00000000 00000000 00000000
[85698.930499] ffc0: 00000000 00000000 00000000 00000000 0867c000 09f50000 020007e0 09f50000
[85698.930503] ffe0: 09f4ffe1 a61fedb8 00033108 00066c60 80080010 ffffffff
[85698.930506] Disabling lock debugging due to kernel taint
[85698.930508] BUG: Bad page state in process metha-sync  pfn:000f1
[85698.936528] page:eedfa1e4 count:0 mapcount:0 mapping:00000000 index:0x1
[85698.943157] flags: 0x400(arch_1)
[85698.946393] raw: 00000400 00000100 00000200 00000000 00000001 00000000 ffffffff 00000000
[85698.954500] raw: 00000000
[85698.957124] page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
[85698.963316] bad because of flags: 0x400(arch_1)
[85698.967854] Modules linked in: tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag nf_tables nfnetlink softdog overlay zstd zram zsmalloc orion_wdt pwm_fan nfsd lm75 marvell_cesa ip_tables x_tables raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 md_mod
[85698.967891] CPU: 1 PID: 31563 Comm: metha-sync Tainted: G    B             4.19.63-mvebu #5.91
[85698.967892] Hardware name: Marvell Armada 380/385 (Device Tree)
...

System details.

tir@helios4:~ $ cat /etc/armbian-release 
# PLEASE DO NOT EDIT THIS FILE
BOARD=helios4
BOARD_NAME="Helios4"
BOARDFAMILY=mvebu
BUILD_REPOSITORY_URL=https://github.com/armbian/build
BUILD_REPOSITORY_COMMIT=0d21d90f
VERSION=5.91
LINUXFAMILY=mvebu
BRANCH=next
ARCH=arm
IMAGE_TYPE=user-built
BOARD_TYPE=conf
INITRD_ARCH=arm
KERNEL_IMAGE_TYPE=zImage

tir@helios4:~ $ cat /etc/os-release 
PRETTY_NAME="Debian GNU/Linux 10 (buster)"
NAME="Debian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

tir@helios4:~ $ go env
GOARCH="arm"
GOBIN=""
GOCACHE="/home/tir/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="arm"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/tir/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/lib/go-1.11"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.11/pkg/tool/linux_arm"
GCCGO="gccgo"
GOARM="6"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -marm -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build486501526=/tmp/go-build -gno-record-gcc-switches"