[FS#1203] Kernel panics reading and writing SD cards using mmc-mtk and kernel 4.9.x

Fri Dec 1 16:15:36 PST 2017

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

User who did this - matt7aylor (matt7aylor) 

Attached to Project - LEDE Project
Summary - Kernel panics reading and writing SD cards using mmc-mtk and kernel 4.9.x
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - High
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - I am getting kernel panics when reading and writing files to SD card / mmc using mt7621 devices and 4.9.x kernel (using mtk_sd driver   included in LEDE trunk via 0046-mmc-MIPS-ralink-add-sdhci-for-mt7620a-SoC.patch). 4.4.x kernels showed no problems.

Occurs with multiple devices (have tested ZBT WG3526 and WE1326 so far), have tried multiple snapshots and compiling from latest trunk, always results in the same problem. No issue on same devices with 17.01.x releases with 4.4.x kernel.

Steps to reproduce:
  - mount mmc partition (seems to mount and create directories ok)
  - copy file to mounted partition (file of correct size will be created but corrupt)
  - OR copy/read files from sd card
  - kernel will panic (see below)

root at LEDE:/# mount /dev/mmcblk0p1 /mnt/
root at LEDE:/# mkdir /mnt/testdir
root at LEDE:/# cp /tmp/4MBfile /mnt/testdir/
root at LEDE:/# [  268.391450] CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 8f6e24ac, ra == 8f6e2480
[  268.402055] Oops[#1]:
[  268.404321] CPU: 0 PID: 415 Comm: mmcqd/0 Not tainted 4.9.65 #0
[  268.410213] task: 8fd76fa0 task.stack: 8f5aa000
[  268.414717] $ 0   : 00000000 80520000 00000080 8054a078
[  268.419937] $ 4   : 8054a088 00000001 fffff495 81490498
[  268.425152] $ 8   : 00000100 00008400 00000000 000a2010
[  268.430368] $12   : 00000001 00000008 00000038 00427ce4
[  268.435581] $16   : 8fe73800 8f6e850c be130000 be130000
[  268.440798] $20   : 8f76c000 00000000 00001000 8fe73a40
[  268.446012] $24   : 00000000 80058e10                  
[  268.451228] $28   : 8f5aa000 8f5abc40 8f6e8434 8f6e2480
[  268.456443] Hi    : 00000003
[  268.459304] Lo    : 00000001
[  268.462190] epc   : 8f6e24ac 0x8f6e24ac
[  268.466007] ra    : 8f6e2480 0x8f6e2480
[  268.469819] Status: 11008403 KERNEL EXL IE 
[  268.473995] Cause : 40800008 (ExcCode 02)
[  268.477978] BadVA : 00000000
[  268.480841] PrId  : 0001992f (MIPS 1004Kc)
[  268.484911] Modules linked in: pppoe ppp_async pppox ppp_generic nf_conntrack_ipv6 mt76x2e mt7603e mt76 mac80211 iptable_nat ipt_REJECT ipt_MASQUERADE cfg80211 xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_mark xt_mac xt_limit xt_conntrack xt_comment xt_TCPMSS xt_REDIRECT xt_LOG slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_conntrack_ipv4 nf_nat_ipv4 nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack iptable_mangle iptable_filter ip_tables crc_ccitt compat ledtrig_usbport 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 mmc_block mtk_sd mmc_core leds_gpio xhci_mtk xhci_plat_hcd xhci_pci xhci_hcd ahci libahci libata sd_mod scsi_mod gpio_button_hotplug usbcore nls_base usb_common
Process mmcqd/0 (pid: 415, threadinfo=8f5aa000, task=8fd76fa0, tls=00000000)
[  268.564700] Stack : 00020002 8f5abc44 8f5abc44 00000000 00000000 8f5abc54 8f5abc54 8f7209e0
[  268.573047]         00000000 00000000 8f6e8000 00000000 0000004e fffff495 804c0000 8f6e851c
[  268.581391]         00000000 8fe73a18 00000001 0000000d 8fe40000 00000900 00000000 00000000
[  268.589733]         00000000 00000195 8fe73800 8f6e8434 8f6e8434 8f6e8688 00000000 8f5abe24
[  268.598078]         8f6e8568 8fe73a18 8f6901c0 8f6e2850 8ff68900 00000001 00000018 8102d700
[  268.606423]         ...
[  268.608863] Call Trace:
[  268.611298] [] 0x8f6e24ac
[  268.614773] Code: 14400009  8fa60034  26a20080  26b50004  ae430018  1455fffc  00000000  26d6ff80 
[  268.624511] 
[  268.626258] ---[ end trace 71c77f6aa019b37d ]---
[  268.632836] Kernel panic - not syncing: Fatal exception
[  268.639868] Rebooting in 3 seconds..

May be related to [[https://bugs.lede-project.org/index.php?do=details&task_id=1011&string=1011&search_name=&type%5B0%5D=&sev%5B0%5D=&pri%5B0%5D=&due%5B0%5D=&reported%5B0%5D=&cat%5B0%5D=&status%5B0%5D=open&percent%5B0%5D=&opened=&dev=&closed=&duedatefrom=&duedateto=&changedfrom=&changedto=&openedfrom=&openedto=&closedfrom=&closedto=|FS#1011]] and [[https://forum.lede-project.org/t/ramips-mt7621-mtk-sd-mediatek-mt6575-msdc-driver-time-sequential-error-with-kernel-4-9-x/4867|LEDE Forum post]]

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1203