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To: Oleg Nesterov Cc: Guo Ren , Vincent Chen , Paul Walmsley , Palmer Dabbelt , linux-riscv , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Oleg Nesterov =E6=96=BC 2020=E5=B9=B45=E6=9C=8826=E6=97= =A5 =E9=80=B1=E4=BA=8C =E4=B8=8B=E5=8D=8810:00=E5=AF=AB=E9=81=93=EF=BC=9A > > On 05/26, Greentime Hu wrote: > > > > @@ -882,13 +882,18 @@ static int ptrace_regset(struct task_struct *task= , int req, unsigned int type, > > const struct user_regset_view *view =3D task_user_regset_view(tas= k); > > const struct user_regset *regset =3D find_regset(view, type); > > int regset_no; > > + unsigned int size; > > > > - if (!regset || (kiov->iov_len % regset->size) !=3D 0) > > + if (!regset) > > return -EINVAL; > > > > regset_no =3D regset - view->regsets; > > - kiov->iov_len =3D min(kiov->iov_len, > > - (__kernel_size_t) (regset->n * regset->size))= ; > > + size =3D regset_size(task, regset); > > + > > + if ((kiov->iov_len % size) !=3D 0) > > + return -EINVAL; > > Hmm. this doesn't look right. > > Before this patch we check "iov_len % regset->size", this is not the same > as "iov_len % regset_size()". > > IOW, currently you can read/write, say, only the 1st register, you patch > breaks this? > Hi Oleg, Thank you. I misunderstood the meaning of regset->size It seems I only needs to update this line, right? - kiov->iov_len =3D min(kiov->iov_len, (__kernel_size_t) (regset->n * regset->size)); + kiov->iov_len =3D min(kiov->iov_len, (__kernel_size_t) regset_size(task, regset));