Hi,
 
I found RAID5 stability issue while doing disk expansion.
I attached 4 disks (/dev/sda, /dev/sdb, /dev/sdc and /dev/sdd) and create partition by “create_partition.sh” scripts on my PC and run my test scripts “raid_reshape_12.sh” (as attached).
Basically, the test will add partitions to RAID5 (/dev/md3) and write files to /dev/md3 (ext4) at the same time.
Within 1 or 2 hours, kernel will get crashed (Oops) and reshape/resync cannot be finished forever (log as attached).
 
The issue happens randomly, but it most likely happens at beginning of reshape process. When kernel crash happens, the reshape stops at about 3-10% complete only.
Moreover, it is not related to any partition size, because I’ve tried different size, but issue still exists.
I've also tried different kernel (4.1/4.2/4.9/4.19/5.4/5.8), and all kernel version can see this issue.

Best Regards,
Winder