On Thu, Mar 17, 2022 at 1:21 AM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> On Wed, Mar 16, 2022 at 05:29:45PM -0700, Rob Clark wrote:
> > switch (param) {
> > + case MSM_PARAM_COMM:
> > + case MSM_PARAM_CMDLINE: {
> > + char *str, **paramp;
> > +
> > + str = kmalloc(len + 1, GFP_KERNEL);
>
> if (!str)
> return -ENOMEM;
>
> > + if (copy_from_user(str, u64_to_user_ptr(value), len)) {
> > + kfree(str);
> > + return -EFAULT;
> > + }
> > +
> > + /* Ensure string is null terminated: */
> > + str[len] = '\0';
> > +
> > + if (param == MSM_PARAM_COMM) {
> > + paramp = &ctx->comm;
> > + } else {
> > + paramp = &ctx->cmdline;
> > + }
> > +
> > + kfree(*paramp);
> > + *paramp = str;
> > +
> > + return 0;
> > + }
> > case MSM_PARAM_SYSPROF:
> > if (!capable(CAP_SYS_ADMIN))
> > return -EPERM;
> > diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
> > index 4ec62b601adc..68f3f8ade76d 100644
> > --- a/drivers/gpu/drm/msm/msm_gpu.c
> > +++ b/drivers/gpu/drm/msm/msm_gpu.c
> > @@ -364,14 +364,21 @@ static void retire_submits(struct msm_gpu *gpu);
> >
> > static void get_comm_cmdline(struct msm_gem_submit *submit, char **comm, char **cmd)
> > {
> > + struct msm_file_private *ctx = submit->queue->ctx;
> > struct task_struct *task;
> >
> > + *comm = kstrdup(ctx->comm, GFP_KERNEL);
> > + *cmd = kstrdup(ctx->cmdline, GFP_KERNEL);
> > +
> > task = get_pid_task(submit->pid, PIDTYPE_PID);
> > if (!task)
> > return;
> >
> > - *comm = kstrdup(task->comm, GFP_KERNEL);
> > - *cmd = kstrdup_quotable_cmdline(task, GFP_KERNEL);
> > + if (!*comm)
> > + *comm = kstrdup(task->comm, GFP_KERNEL);
>
> What?
>
> If the first allocation failed, then this one is going to fail as well.
> Just return -ENOMEM. Or maybe this is meant to be checking for an empty
> string?
fwiw, if ctx->comm is NULL, the kstrdup() will return NULL, so this
isn't intended to deal with OoM, but the case that comm and/or cmdline
is not overridden.
BR,
-R
>
> > +
> > + if (!*cmd)
> > + *cmd = kstrdup_quotable_cmdline(task, GFP_KERNEL);
>
> Same.
>
> >
> > put_task_struct(task);
> > }
>
> regards,
> dan carpenter
>
