> Hello, > > Thank you revisit this. But as far as my remember is correct, this issue is NOT > unaligned access issue. It's just get_user_pages(_fast) vs fork race issue. i.e. > DIRECT_IO w/ multi thread process should not use fork(). The problem is, fork (and its COW logic) assume new access makes cow break, But page table protection can't detect a DMA write. Therefore DIO may override shared page data. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
