On Mon, Mar 15, 2021 at 01:08:03PM +0100, Oleg Nesterov wrote: > On 03/14, Alexey Dobriyan wrote: > > > > prctl(PR_SET_MM, PR_SET_MM_AUXV, addr, 1); > > > > will copy 1 byte from userspace to (quite big) on-stack array > > and then stash everything to mm->saved_auxv. > > I too don't understand, memcpy(mm->saved_auxv, user_auxv, len) will > copy 1 byte...
Indeed. I overlooked that we pass @len when copying. I should not reply at night :( > > And why task_lock(current) ? What does it try to protect? As far as I remember this was related to reading from procfs at time the patch was written for first time. Looks like this not relevant anymore and could be dropped.
