From: Oleg Nesterov <oleg@redhat.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Benjamin LaHaise <bcrl@kvack.org>,
Hugh Dickins <hughd@google.com>, Jeff Moyer <jmoyer@redhat.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] mremap: don't do mm_populate(new_addr) on failure
Date: Wed, 1 Jul 2015 17:47:43 +0200 [thread overview]
Message-ID: <20150701154743.GB14934@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1506301533150.24266@chino.kir.corp.google.com>
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.
next prev parent reply other threads:[~2015-07-01 15:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-19 23:18 [PATCH 0/4] mremap fix/cleanups Oleg Nesterov
2015-06-19 23:19 ` [PATCH 1/4] mremap: don't leak new_vma if f_op->mremap() fails Oleg Nesterov
2015-06-30 22:31 ` David Rientjes
2015-07-01 15:46 ` Oleg Nesterov
2015-07-01 22:55 ` David Rientjes
2015-06-19 23:19 ` [PATCH 2/4] mremap: don't do mm_populate(new_addr) on failure Oleg Nesterov
2015-06-30 22:34 ` David Rientjes
2015-07-01 15:47 ` Oleg Nesterov [this message]
2015-07-01 21:45 ` David Rientjes
2015-07-01 22:41 ` Oleg Nesterov
2015-06-19 23:19 ` [PATCH 3/4] mremap: don't do uneccesary checks if new_len == old_len Oleg Nesterov
2015-06-30 22:36 ` David Rientjes
2015-06-19 23:19 ` [PATCH 4/4] mremap: simplify the "overlap" check in mremap_to() Oleg Nesterov
2015-06-30 22:45 ` David Rientjes
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