In the Linux kernel, the following vulnerability has been resolved:
md/raid1: Fix data corruption for degraded array with slow disk
read_balance() will avoid reading from slow disks as much as possible, however, if valid data only lands in slow disks, and a new normal disk is still in recovery, unrecovered data can be read:
raid1readrequest readbalance raid1shouldreadfirst -> return false choosebestrdev -> normal disk is not recovered, return -1 choosebbrdev -> missing the checking of recovery, return the normal disk -> read unrecovered data
Root cause is that the checking of recovery is missing in choosebbrdev(). Hence add such checking to fix the problem.
Also fix similar problem in chooseslowrdev().