Messages in this thread | | | Date | Wed, 1 Jul 2015 17:47:43 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 2/4] mremap: don't do mm_populate(new_addr) on failure |
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On 06/30, David Rientjes wrote: > > On Sat, 20 Jun 2015, Oleg Nesterov wrote: > > > --- a/mm/mremap.c > > +++ b/mm/mremap.c > > @@ -574,8 +574,10 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, > > ret = move_vma(vma, addr, old_len, new_len, new_addr, &locked); > > } > > out: > > - if (ret & ~PAGE_MASK) > > + if (ret & ~PAGE_MASK) { > > vm_unacct_memory(charged); > > + locked = 0; > > + } > > up_write(¤t->mm->mmap_sem); > > if (locked && new_len > old_len) > > mm_populate(new_addr + old_len, new_len - old_len); > > Perhaps I'm looking at the wrong tree (next-20150630), but why does > setting locked to 0 here matter if it's unreferenced?
See the "if (locked && ...)" check before mm_populate(). We should not do this if move_vma() fails.
Oleg.
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