平台：Allwinner H3
系统：OpenWrt linux
出错特点： reboot 后概率出现，下次启动又正常。
log :

[    1.781438] Key type dns_resolver registered
[    1.785824] Registering SWP/SWPB emulation handler
[    1.795843] hctosys: unable to open rtc device (rtc0)
[    1.801462] vcc3v0: disabling
[    1.804431] vcc3v3: disabling
[    1.807396] vcc5v0: disabling
[    1.810378] ALSA device list:
[    1.813343]   No soundcards found.
[    1.887068] VFS: Mounted root (squashfs filesystem) readonly on device 31:4.
[    1.896322] Freeing unused kernel memory: 2048K
[    1.941487] random: crng init done
[    2.747800] NOHZ: local_softirq_pending 282
[    2.752001] NOHZ: local_softirq_pending 282
[    2.756185] NOHZ: local_softirq_pending 282
[    2.760372] NOHZ: local_softirq_pending 282
[    2.764551] NOHZ: local_softirq_pending 282
[    2.768736] NOHZ: local_softirq_pending 282
[    2.772919] NOHZ: local_softirq_pending 282
[    2.777103] NOHZ: local_softirq_pending 282
[    2.781286] NOHZ: local_softirq_pending 282
[    2.863388] SQUASHFS error: xz decompression failed, data probably corrupt
[    2.870281] SQUASHFS error: squashfs_read_data failed to read block 0x1fd9ce
[    2.877320] SQUASHFS error: Unable to read fragment cache entry [1fd9ce]
[    2.884024] SQUASHFS error: Unable to read page, block 1fd9ce, size 2bcc
[    2.890740] SQUASHFS error: Unable to read fragment cache entry [1fd9ce]
[    2.897431] SQUASHFS error: Unable to read page, block 1fd9ce, size 2bcc
[    2.904139] SQUASHFS error: Unable to read fragment cache entry [1fd9ce]
[    2.910841] SQUASHFS error: Unable to read page, block 1fd9ce, size 2bcc
[    2.917536] SQUASHFS error: Unable to read fragment cache entry [1fd9ce]
[    2.924239] SQUASHFS error: Unable to read page, block 1fd9ce, size 2bcc
[    2.930949] SQUASHFS error: Unable to read fragment cache entry [1fd9ce]
[    2.937640] SQUASHFS error: Unable to read page, block 1fd9ce, size 2bcc
/sbin/init: error while loading shared libraries: /lib/librt.so.1: cannot read file data: Input/output error
[    2.977864] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00007f00
[    2.977864] 

分析：
1，因为是概率出现，说明squashfs rootfs 本身没有问题。
2，尝试 降 spi 时钟频率，加上拉电阻等办法都没有用
3，最后怀疑 NOHZ: local_softirq_pending 这地方有关，修改后问题不再复现。

解决办法：

--- a/target/linux/sunxi/config-4.14
+++ b/target/linux/sunxi/config-4.14
@@ -289,6 +289,7 @@ CONFIG_HW_CONSOLE=yCONFIG_HW_RANDOM=yCONFIG_HW_RANDOM_TIMERIOMEM=yCONFIG_HZ_FIXED=0
+CONFIG_HZ_PERIODIC=yCONFIG_I2C=yCONFIG_I2C_BOARDINFO=yCONFIG_I2C_CHARDEV=y
@@ -377,9 +378,6 @@ CONFIG_NLS=yCONFIG_NLS_CODEPAGE_437=yCONFIG_NLS_ISO8859_1=yCONFIG_NO_BOOTMEM=y
-CONFIG_NO_HZ=y
-CONFIG_NO_HZ_COMMON=y
-CONFIG_NO_HZ_IDLE=yCONFIG_NR_CPUS=8CONFIG_NVMEM=yCONFIG_NVMEM_SUNXI_SID=y

原因猜测：
可能是配置了 CONFIG_NO_HZ_IDLE 时 cpu 的 tick 停摆了导致 spi 读写异常。