Messages in this thread | | | Date | Mon, 11 Dec 2017 13:13:02 +0100 | From | Peter Zijlstra <> | Subject | Re: [patch V2 2/2] x86/ldt: Prevent ldt inheritance on exec |
| |
On Sat, Dec 09, 2017 at 07:24:35PM +0100, Thomas Gleixner wrote: > On Fri, 8 Dec 2017, Thomas Gleixner wrote: > > +int ldt_dup_context(struct mm_struct *old_mm, struct mm_struct *mm) > > { > > struct ldt_struct *new_ldt; > > - struct mm_struct *old_mm; > > int retval = 0; > > > > - mutex_init(&mm->context.lock); > > - old_mm = current->mm; > > - if (!old_mm) { > > - mm->context.ldt = NULL; > > + if (!old_mm) > > return 0; > > - } > > > > mutex_lock(&old_mm->context.lock); > > Bah. That's broken. It now nests into old_mm->mmap_sem which is the reverse > lock order than in ldt_write. Will fix.
But read_ldt() will still nest mmap_sem inside context.lock, no? Lockdep doesn't care about old_mm vs new_mm.
| |