On 2020/08/07 22:41, Ming Lei wrote: >> FWIW, my preference would be to have for_each_bvec() advance past zero-length >> segments; I'll need to go through its uses elsewhere in the tree first, though >> (after I grab some sleep), > > Usually block layer doesn't allow/support zero bvec, however we can make > for_each_bvec() to support it only. > > Tetsuo, can you try the following patch? Yes, this patch solves the lockup. Thank you.