In the Linux kernel, the following vulnerability has been resolved:Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"This reverts commit 5e2cf333b7bd5d3e62595a44d598a254c697cd74.That commit introduced the following race and can cause system hung.md_write_start:             raid5d:
 // mddev->in_sync == 1
 set "MD_SB_CHANGE_PENDING"
                            // running before md_write_start wakeup it
                             waiting "MD_SB_CHANGE_PENDING" cleared
                             >>>>>>>>> hung
 wakeup mddev->thread
 ...
 waiting "MD_SB_CHANGE_PENDING" clearedhung, raid5d should clear this flag
 but get hung by same flag.The issue reverted commit fixing is fixed by last patch in a new way.