Mostly that the issue only appears when rclone is run, and given the binary is not available in the entware repositories for OpenWRT, I'm not too sure how likely I am to receive a response over on their forums (Docker and docker-compose on the other hand are available, for example).
If so, the only piece I think may be relevant is the following:
From system.log, a reload happens between line 46508 (where rclone was asked to read from a file) to line 46509, where the kernel starts booting up from scratch, indicated by fstab reloading sda1 and enumerating possible mount points) until service begin getting started around lines 4662*, specifically starting the configured init script for rclone in line 46624, where rclone seems unable to find its config file (normally located and not moved from /root/.config/rclone/rclone.conf). I am not sure if manually setting the location of the config file within the init script would change this situation, as manually calling the init script after the whole system has loaded proves successful.
We then go all the way until line 47754, where a kernel warning starts and outputs a trace until line 47797, which goes as follows:
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 188.732032] ------------[ cut here ]------------
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 188.736660] deprecated, use hwmon sysfs instead
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 188.741227] WARNING: CPU: 0 PID: 29057 at drivers/firmware/raspberrypi.c:237 get_throttled_show+0x64/0x70
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 188.750785] Modules linked in: qcserial pppoe ppp_async option l2tp_ppp cdc_mbim brcmfmac wireguard usb_wwan sr9700 smsc95xx sierra_net sierra rndis_host qmi_wwan pppox ppp_generic pl2303 libchacha20poly1305 libblake2s iscsi_tcp ipt_REJECT huawei_cdc_ncm ftdi_sio dm9601 chacha_neon ch341 cfg80211 cdc_ncm cdc_ether ax88179_178a asix aqc111 zstd xt_time xt_tcpudp xt_tcpmss xt_statistic xt_state xt_recent xt_quota2 xt_quota xt_pkttype xt_owner xt_nat xt_multiport xt_mark xt_mac xt_limit xt_length xt_hl xt_helper xt_hashlimit xt_geoip xt_ecn xt_dscp xt_conntrack xt_connmark xt_connlimit xt_connbytes xt_comment xt_cgroup xt_addrtype xt_TEE xt_TCPMSS xt_REDIRECT xt_MASQUERADE xt_LOG xt_HL xt_FLOWOFFLOAD xt_DSCP xt_CT xt_CLASSIFY usbserial usbnet usbhid ums_usbat ums_sddr55 ums_sddr09 ums_karma ums_jumpshot ums_isd200 ums_freecom ums_datafab ums_cypress ums_alauda slhc sch_cake rtl8150 r8169 poly1305_neon pegasus nft_reject_ipv6 nft_reject_ipv4 nft_reject_inet nft_reject_bridge nft_reject
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 188.750915] nft_redir nft_quota nft_objref nft_numgen nft_meta_bridge nft_log nft_limit nft_hash nft_fwd_netdev nft_dup_netdev nft_ct nft_counter nf_tables nf_reject_ipv4 nf_log_ipv4 nf_flow_table nf_dup_netdev nf_dup_ipv6 nf_dup_ipv4 nf_conntrack_netlink nf_conncount macvlan lzo libiscsi_tcp libiscsi libcurve25519_generic libchacha libblake2s_generic iptable_raw iptable_nat iptable_mangle iptable_filter ipt_ECN ip6table_raw ip_tables hid_generic crc_ccitt compat cdc_wdm cdc_acm brcmutil br_netfilter spi_bcm2835 fuse sch_teql sch_sfq sch_red sch_prio sch_pie sch_multiq sch_gred sch_fq sch_dsmark sch_codel em_text em_nbyte em_meta em_cmp act_simple act_police act_pedit act_ipt act_csum cls_bpf act_bpf act_ctinfo sch_tbf sch_ingress sch_htb sch_hfsc em_u32 cls_u32 cls_tcindex cls_route cls_matchall cls_fw cls_flow cls_basic act_skbedit act_mirred act_gact snd_bcm2835(C) hid pwm_bcm2835 evdev i2c_bcm2835 usb_f_acm u_serial usb_f_mass_storage usb_f_hid usb_f_ecm u_ether i2c_dev libcomposite
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 188.837971] ledtrig_usbport ledtrig_oneshot ledtrig_gpio cryptodev xt_set ip_set_list_set ip_set_hash_netportnet ip_set_hash_netport ip_set_hash_netnet ip_set_hash_netiface ip_set_hash_net ip_set_hash_mac ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_hash_ipport ip_set_hash_ipmark ip_set_hash_ip ip_set_bitmap_port ip_set_bitmap_ipmac ip_set_bitmap_ip ip_set nfnetlink ip6table_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip6t_NPT ip6t_rt ip6t_mh ip6t_ipv6header ip6t_hbh ip6t_frag ip6t_eui64 ip6t_ah nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables ip6t_REJECT x_tables nf_reject_ipv6 nfsv4 nfsd nfs nfs_ssc bonding ip6_gre ip_gre gre ifb dummy sit l2tp_netlink l2tp_core udp_tunnel ip6_udp_tunnel ipip ip6_tunnel tunnel6 tunnel4 ip_tunnel rpcsec_gss_krb5 auth_rpcgss oid_registry veth tun snd_rawmidi snd_seq_device snd_pcm_oss snd_pcm_dmaengine snd_mixer_oss snd_hwdep snd_compress snd_pcm snd_timer snd soundcore lockd sunrpc grace isofs hfsplus cdrom cifs
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 188.925537] dns_resolver dm_mirror dm_region_hash dm_log dm_crypt dm_mod dax nls_utf8 crypto_user algif_skcipher algif_rng algif_hash algif_aead af_alg sha1_generic md5 md4 kpp des_generic libdes cmac authenc arc4 crypto_acompress vfat fat nls_iso8859_1 nls_cp437 dwc2 roles uhci_hcd ohci_platform ohci_hcd ledtrig_transient fsl_mph_dr_of ehci_platform ehci_fsl ehci_hcd gpio_button_hotplug exfat btrfs xor zstd_decompress zstd_compress zlib_inflate zlib_deflate xxhash xor_neon raid6_pq lzo_decompress lzo_compress libcrc32c realtek encrypted_keys trusted tpm
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.061705] CPU: 0 PID: 29057 Comm: python3 Tainted: G C 5.10.88 #0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.069266] Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT)
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.075095] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO BTYPE=--)
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.081101] pc : get_throttled_show+0x64/0x70
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.085455] lr : get_throttled_show+0x64/0x70
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.089803] sp : ffffffc011babc20
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.093110] x29: ffffffc011babc20 x28: ffffff804120b0b0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.098414] x27: 0000000000400cc0 x26: ffffff804120b0a0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.103718] x25: 0000000000000000 x24: ffffff80a44e9a00
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.109023] x23: ffffff80402fb010 x22: ffffff8047205000
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.114327] x21: ffffffc0107eb0a0 x20: ffffff80402a6f00
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.119631] x19: ffffff8047205000 x18: 000000000000037c
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.124934] x17: 0000000000000000 x16: 0000000000000000
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.130237] x15: ffffffc010a278d0 x14: 0000000000000a74
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.135541] x13: 000000000000237c x12: ffffffc011bab8f8
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.140844] x11: 000000000004cd70 x10: 000000000004cd10
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.146147] x9 : ffffffc010a7f8d0 x8 : 00000000000053a0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.151450] x7 : ffffffc010a278d0 x6 : 0000000000000001
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.156753] x5 : ffffff80fb8266b0 x4 : 0000000000000000
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.162057] x3 : 0000000000000027 x2 : 0000000000000027
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.167361] x1 : 0000000000000023 x0 : 0000000000000023
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.172665] Call trace:
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.175115] get_throttled_show+0x64/0x70
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.179125] dev_attr_show+0x20/0x5c
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.182697] sysfs_kf_seq_show+0x88/0x130
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.186700] kernfs_seq_show+0x2c/0x40
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.190444] seq_read_iter+0x1bc/0x4a0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.194186] kernfs_fop_read_iter+0x150/0x1d0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.198536] new_sync_read+0xd4/0x150
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.202193] vfs_read+0x11c/0x1a0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.205500] ksys_read+0x58/0xe0
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.208722] __arm64_sys_read+0x1c/0x30
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.212554] do_el0_svc+0xbc/0x140
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.215951] el0_svc+0x14/0x20
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.219000] el0_sync_handler+0xa4/0x140
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.222915] el0_sync+0x164/0x180
Thu Dec 30 02:06:25 2021 kern.warn kernel: [ 189.226221] ---[ end trace c9e8e9273e9271cb ]---
The DHCP server restarts a couple more times, then the log cuts off.
system.log.old just includes queries related to file accesses, but coincides with the Access denied issue, as whenever I try to open this particular file, I just receive an error stated as <nil>
Wed Dec 29 23:23:31 2021 kern.debug rclone[1994]: Pictures/My Nintendo Wallpapers/: Lookup: name="December calendar - Xenoblade Chronicles 2"
Wed Dec 29 23:23:31 2021 kern.debug rclone[1994]: Pictures/My Nintendo Wallpapers/: >Lookup: node=Pictures/My Nintendo Wallpapers/December calendar - Xenoblade Chronicles 2/, err=<nil>
The Pi is inside a case with an onboard fan, highest I've got so far has been 68°C, so far no overheating.
Going through the log just now, I'm honestly not too sure where and when is the problem occurring, and given the only common factor is rclone itself, I don't know how would I go about asking for help or troubleshooting in a reliable manner (perhaps by using debug symbols or something of the sort I would be able to get even more verbosity), but as of right now all I can think of is that perhaps attempting to run rclone within a Docker container would isolate the router's OS environment being the primary issue.
Until then, if there's any pointers you could give me as to what else I could try to isolate the root cause, I'd be glad to see is there's any way around this issue.
Cheers!