On Fri, Nov 27, 2020 at 01:07:38PM +0800, Miles Chen wrote: > Cc: Will Deacon <will.deacon@xxxxxxx> That should be will@xxxxxxxxxx. > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 217aa2705d5d..92b277388f05 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -1599,11 +1599,15 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, > > src = *ppos; > svpfn = src / PM_ENTRY_BYTES; > - start_vaddr = svpfn << PAGE_SHIFT; > end_vaddr = mm->task_size; > > /* watch out for wraparound */ > - if (svpfn > mm->task_size >> PAGE_SHIFT) > + start_vaddr = end_vaddr; > + if (svpfn < (ULONG_MAX >> PAGE_SHIFT)) Does this need to be strict less-than? I think a less-than or equal would work better. > + start_vaddr = untagged_addr(svpfn << PAGE_SHIFT); > + > + /* Ensure the address is inside the task */ > + if (start_vaddr > mm->task_size) > start_vaddr = end_vaddr; Otherwise the logic looks fine to me. With the above: Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
