[FS#1550] Unable to handle kernel paging request causes router to reboot

Wed May 16 02:07:36 PDT 2018

A new Flyspray task has been opened.  Details are below. 

User who did this - Bartosz Markocki (bartekm) 

Attached to Project - OpenWrt/LEDE Project
Summary - Unable to handle kernel paging request causes router to reboot
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Critical
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details -  - Device problem occurs on
Xiaomi mi router 3G (R3G)

 - Software versions of OpenWrt/LEDE release, packages, etc.
Latest trunk (r6893-bfbdeeb) custom build

 - Steps to reproduce
Did not notice there is a pattern here.   

 - The issue
The kernel crash causes the router to reboot. Here are two traces I was able to catch

May 13 07:24:52 router kernel: [82948.434471] CPU 1 Unable to handle kernel paging request at virtual address 07407800, epc == 80136a70, ra == 8013694c
May 13 07:24:52 router kernel: [82948.445103] Oops[#1]:
May 13 07:24:52 router kernel: [82948.447387] CPU: 1 PID: 1977 Comm: kworker/u8:1 Not tainted 4.14.37 #0
May 13 07:24:52 router kernel: [82948.453909] Workqueue: writeback wb_workfn (flush-8:0)
May 13 07:24:52 router kernel: [82948.459046] task: 8ff3ddc0 task.stack: 8dd62000
May 13 07:24:52 router kernel: [82948.463565] $ 0   : 00000000 00000001 00000000 812286b0
May 13 07:24:52 router kernel: [82948.468800] $ 4   : 805aa44c 00000001 00000001 07407800
May 13 07:24:52 router kernel: [82948.474019] $ 8   : 000facb3 000facb2 00000002 00064000
May 13 07:24:52 router kernel: [82948.479248] $12   : 00000009 0004001a fffeffff 00001000
May 13 07:24:52 router kernel: [82948.484473] $16   : 8fc02c00 000001b8 01011200 8022b6f0
May 13 07:24:52 router kernel: [82948.489695] $20   : 8ebb0000 8006a664 8e56d81c 01400000
May 13 07:24:52 router kernel: [82948.494913] $24   : 81196320 00000000
May 13 07:24:52 router kernel: [82948.500133] $28   : 8dd62000 8dd63950 8fd77d40 8013694c
May 13 07:24:52 router kernel: [82948.505351] Hi    : 00000000
May 13 07:24:52 router kernel: [82948.508214] Lo    : 00840480
May 13 07:24:52 router kernel: [82948.511113] epc   : 80136a70 __kmalloc+0x1f8/0x2ec
May 13 07:24:52 router kernel: [82948.515887] ra    : 8013694c __kmalloc+0xd4/0x2ec
May 13 07:24:52 router kernel: [82948.520568] Status: 11007c03#011KERNEL EXL IE
May 13 07:24:52 router kernel: [82948.524750] Cause : 40800008 (ExcCode 02)
May 13 07:24:52 router kernel: [82948.528740] BadVA : 07407800
May 13 07:24:52 router kernel: [82948.531605] PrId  : 0001992f (MIPS 1004Kc)
May 13 07:24:52 router kernel: [82948.535679] Modules linked in: pppoe ppp_async pppox ppp_generic nf_conntrack_ipv6 mt76x2e mt7603e mt76 mac80211 iptable_nat ipt_REJECT ipt_MASQUERADE cfg80211 cdc_ether xt_time xt_tcpudp xt_tcpmss xt_statistic xt_state xt_recent xt_nat xt_multiport xt_mark xt_mac xt_limit xt_length xt_hl xt_helper xt_ecn xt_dscp xt_conntrack xt_connmark xt_connlimit xt_connbytes xt_comment xt_TCPMSS xt_REDIRECT xt_LOG xt_HL xt_FLOWOFFLOAD xt_DSCP xt_CLASSIFY usbnet slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_conntrack_ipv4 nf_nat_ipv4 nf_nat nf_log_ipv4 nf_flow_table_hw nf_flow_table nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack libcrc32c iptable_mangle iptable_filter ipt_ECN ip_tables crc_ccitt compat ledtrig_usbport xt_set ip_set_list_set ip_set_hash_netiface ip_set_hash_netport
May 13 07:24:52 router kernel: [82948.606444]  ip_set_hash_netnet ip_set_hash_net ip_set_hash_netportnet 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 ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables vfat fat nls_utf8 nls_iso8859_1 nls_cp437 usb_storage leds_gpio xhci_mtk xhci_plat_hcd xhci_pci xhci_hcd sd_mod scsi_mod gpio_button_hotplug ext4 jbd2 mbcache usbcore nls_base usb_common mii crc32c_generic
May 13 07:24:52 router kernel: [82948.655996] Process kworker/u8:1 (pid: 1977, threadinfo=8dd62000, task=8ff3ddc0, tls=00000000)
May 13 07:24:52 router kernel: [82948.664578] Stack : 01011200 00400000 8006a664 8f0c719c 00000001 00000000 8fd33300 01011200
May 13 07:24:52 router kernel: [82948.672925]         8fe74850 01011200 00000001 00400000 8006a664 8022b6f0 8fe74850 01011200
May 13 07:24:52 router kernel: [82948.681267]         01411200 8fdf9e00 01011200 01411200 8e56d800 800ecd30 8fe74850 01011200
May 13 07:24:52 router kernel: [82948.689609]         01411200 8fdf9d00 01400000 00400000 8006a664 800ecd30 00060000 00000001
May 13 07:24:52 router kernel: [82948.697952]         8dd63a48 8fe74850 00000000 8fe74850 00000001 8fe74850 00000000 8fe74878
May 13 07:24:52 router kernel: [82948.706292]         ...
May 13 07:24:52 router kernel: [82948.708733] Call Trace:
May 13 07:24:52 router kernel: [82948.711201] [] __kmalloc+0x1f8/0x2ec
May 13 07:24:52 router kernel: [82948.715643] [] alloc_request_size+0x2c/0x7c
May 13 07:24:52 router kernel: [82948.720708] [] mempool_alloc+0x6c/0x178
May 13 07:24:52 router kernel: [82948.725402] [] get_request+0x360/0x76c
May 13 07:24:52 router kernel: [82948.730005] [] blk_queue_bio+0x1cc/0x430
May 13 07:24:52 router kernel: [82948.734781] [] generic_make_request+0xd8/0x288
May 13 07:24:52 router kernel: [82948.740078] [] submit_bio+0x124/0x164
May 13 07:24:52 router kernel: [82948.744663] [] ext4_io_submit+0x50/0x64 [ext4]
May 13 07:24:52 router kernel: [82948.749989] [] ext4_mark_inode_dirty+0xeac/0x1368 [ext4]
May 13 07:24:52 router kernel: [82948.756166] Code: 32428000  8e020014  00e23821  1000002c  cc400000  1280ffbc  00000000  8e060010
May 13 07:24:52 router kernel: [82948.765910]
May 13 07:24:52 router kernel: [82948.767638] ---[ end trace e8f9893fb33e6a26 ]---

and the second case

May 15 15:52:16 router kernel: [67618.480256] CPU 0 Unable to handle kernel paging request at virtual address 07402800, epc == 80136784, ra == 800ecd30
May 15 15:52:16 router kernel: [67618.490997] Oops[#1]:
May 15 15:52:16 router kernel: [67618.493275] CPU: 0 PID: 14159 Comm: kworker/u8:1 Not tainted 4.14.37 #0
May 15 15:52:16 router kernel: [67618.499875] Workqueue: writeback wb_workfn (flush-8:0)
May 15 15:52:16 router kernel: [67618.504997] task: 8c3276c0 task.stack: 8b656000
May 15 15:52:16 router kernel: [67618.509500] $ 0   : 00000000 00000001 00000000 8121a6c0
May 15 15:52:16 router kernel: [67618.514709] $ 4   : 805aa44c 00000001 00000001 07402800
May 15 15:52:16 router kernel: [67618.519918] $ 8   : 00005ddf 00005dde 8fb9b6a0 00000120
May 15 15:52:16 router kernel: [67618.525127] $12   : 8000001f 00000010 00000124 00000001
May 15 15:52:16 router kernel: [67618.530336] $16   : 8fd4a200 01011200 800ecd30 8b0e0000
May 15 15:52:16 router kernel: [67618.535545] $20   : 00400000 8006a664 8fd4981c 80660000
May 15 15:52:16 router kernel: [67618.540754] $24   : ffffffe0 ffff0000
May 15 15:52:16 router kernel: [67618.545963] $28   : 8b656000 8b657970 8f1c2c24 800ecd30
May 15 15:52:16 router kernel: [67618.551174] Hi    : 00000000
May 15 15:52:16 router kernel: [67618.554035] Lo    : 008402f0
May 15 15:52:16 router kernel: [67618.556924] epc   : 80136784 kmem_cache_alloc+0x13c/0x230
May 15 15:52:16 router kernel: [67618.562323] ra    : 800ecd30 mempool_alloc+0x6c/0x178
May 15 15:52:16 router kernel: [67618.567345] Status: 11008403#011KERNEL EXL IE
May 15 15:52:16 router kernel: [67618.571515] Cause : 40800008 (ExcCode 02)
May 15 15:52:16 router kernel: [67618.575499] BadVA : 07402800
May 15 15:52:16 router kernel: [67618.578361] PrId  : 0001992f (MIPS 1004Kc)
May 15 15:52:16 router kernel: [67618.582431] Modules linked in: pppoe ppp_async pppox ppp_generic nf_conntrack_ipv6 mt76x2e mt7603e mt76 mac80211 iptable_nat ipt_REJECT ipt_MASQUERADE cfg80211 cdc_ether xt_time xt_tcpudp xt_tcpmss xt_statistic xt_state xt_recent xt_nat xt_multiport xt_mark xt_mac xt_limit xt_length xt_hl xt_helper xt_ecn xt_dscp xt_conntrack xt_connmark xt_connlimit xt_connbytes xt_comment xt_TCPMSS xt_REDIRECT xt_LOG xt_HL xt_FLOWOFFLOAD xt_DSCP xt_CLASSIFY usbnet slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_conntrack_ipv4 nf_nat_ipv4 nf_nat nf_log_ipv4 nf_flow_table_hw nf_flow_table nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack libcrc32c iptable_mangle iptable_filter ipt_ECN ip_tables crc_ccitt compat ledtrig_usbport xt_set ip_set_list_set ip_set_hash_netiface ip_set_hash_netport
May 15 15:52:16 router kernel: [67618.653177]  ip_set_hash_netnet ip_set_hash_net ip_set_hash_netportnet 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 ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables vfat fat nls_utf8 nls_iso8859_1 nls_cp437 usb_storage leds_gpio xhci_mtk xhci_plat_hcd xhci_pci xhci_hcd sd_mod scsi_mod gpio_button_hotplug ext4 jbd2 mbcache usbcore nls_base usb_common mii crc32c_generic
May 15 15:52:16 router kernel: [67618.702675] Process kworker/u8:1 (pid: 14159, threadinfo=8b656000, task=8c3276c0, tls=00000000)
May 15 15:52:16 router kernel: [67618.711326] Stack : 8e648b20 8f147e00 8e648b20 01011200 00000001 8022b710 00000002 01011200
May 15 15:52:16 router kernel: [67618.719658]         01411200 8fd49800 01400000 00400000 8006a664 800ecd30 00000001 01011200
May 15 15:52:16 router kernel: [67618.727990]         01411200 8fd49700 01400000 00400000 8006a664 800ecd30 8e330030 8c499000
May 15 15:52:16 router kernel: [67618.736322]         8fd9f000 8b657a2c 01400000 8fd49800 01400000 01400000 8e47fa00 8d44d8f8
May 15 15:52:16 router kernel: [67618.744655]         80660000 80225974 8fd49600 00000100 01400000 8d48d7c0 8e47fa00 8fd49600
May 15 15:52:16 router kernel: [67618.752989]         ...
May 15 15:52:16 router kernel: [67618.755425] Call Trace:
May 15 15:52:16 router kernel: [67618.757859] [] kmem_cache_alloc+0x13c/0x230
May 15 15:52:16 router kernel: [67618.762897] [] mempool_alloc+0x6c/0x178
May 15 15:52:16 router kernel: [67618.767596] [] bvec_alloc+0xdc/0x154
May 15 15:52:16 router kernel: [67618.772020] [] bio_alloc_bioset+0x158/0x250
May 15 15:52:16 router kernel: [67618.777111] [] ext4_bio_write_page+0x320/0x5c4 [ext4]
May 15 15:52:16 router kernel: [67618.783028] [] ext4_convert_inline_data+0x874/0x21a8 [ext4]
May 15 15:52:16 router kernel: [67618.789461] [] ext4_convert_inline_data+0xce0/0x21a8 [ext4]
May 15 15:52:16 router kernel: [67618.795881] Code: 32228000  8e020014  00e23821  1000002d  cc400000  1260ffbc  00000000  8e060010
May 15 15:52:16 router kernel: [67618.805607]
May 15 15:52:16 router kernel: [67618.807332] ---[ end trace 3b32ff5399a1bc64 ]---

More information can be found at the following URL:
https://bugs.openwrt.org/index.php?do=details&task_id=1550