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> > - if (copy_from_user(kbuf, buffer + done, size)) > + if (copy_from_user_nul(kbuf, buffer + done, size)) > return -EFAULT; This hides the original error. Can you switch it to: err = copy_xxx(); if (err) return err; I understand that in this case EFAULT is the only possible error, but the above pattern is really error-prone, and is reproduced again and again over the kernel. > - kbuf[size] = '\0'; > buf = kbuf; > do { > tmp = strchr(buf, '\n'); > -- > 2.36.1