Messages in this thread | | | Date | Fri, 15 Jun 2012 14:10:31 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 2/3] uprobes: __copy_insn() should ensure a_ops->readpage != NULL |
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* Srikar Dronamraju <srikar@linux.vnet.ibm.com> wrote:
> * Oleg Nesterov <oleg@redhat.com> [2012-06-07 19:00:18]: > > > __copy_insn() blindly calls read_mapping_page(), this will crash > > the kernel if ->readpage == NULL, add the necessary check. For > > example, hugetlbfs_aops->readpage is NULL. Perhaps we should change > > read_mapping_page() instead. > > > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > --- > > kernel/events/uprobes.c | 2 ++ > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > > index 48d53af..9c53bc2 100644 > > --- a/kernel/events/uprobes.c > > +++ b/kernel/events/uprobes.c > > @@ -616,6 +616,8 @@ __copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *ins > > > > if (!filp) > > return -EINVAL; > > + if (!mapping->a_ops->readpage) > > + return -EIO; > > Nit: Should there be a blank line before the if. Ingo had insisted on > these coding style changes.
Well, within sensible limits: if()'s can certainly be in a block if they do related things (such as boundary checks, etc.), so the above isn't ugly IMO.
Nor are separating newlines strictly necessary - it's also a function of the complexity of the code in question - if it's complex code then we want all visual and cleanliness help that we can think of.
Thanks,
Ingo
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