On Sun, Apr 24, 2022 at 05:11:03PM +0800, Miaohe Lin wrote: > There is a bug in unuse_pte(): when swap page happens to be unreadable, > page filled with random data is mapped into user address space. In case > of error, a special swap entry indicating swap read fails is set to the > page table. So the swapcache page can be freed and the user won't end up > with a permanently mounted swap because a sector is bad. And if the page > is accessed later, the user process will be killed so that corrupted data > is never consumed. On the other hand, if the page is never accessed, the > user won't even notice it. > > Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> > Acked-by: David Hildenbrand <david@xxxxxxxxxx> When I reproduced the issue (generated read error with dm-dust), I saw infinite loop in the while loop in shmem_unuse_inode() (and this happens even with this patch). I confirmed that shmem_swapin_page() returns -EIO, but shmem_unuse_swap_entries() does not return the error to the callers, so the while loop in shmem_unuse_inode() seems not break. So maybe you need more code around shmem_unuse_inode() to handle the error? Thanks, Naoya Horiguchi
