Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Sun, 25 Mar 2018 15:10:29 -0700 (PDT)
From:   David Rientjes <rientjes@google.com>
To:     Laurent Dufour <ldufour@linux.vnet.ibm.com>
cc:     kernel test robot <fengguang.wu@intel.com>,
        paulmck@linux.vnet.ibm.com, peterz@infradead.org,
        akpm@linux-foundation.org, kirill@shutemov.name,
        ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net,
        jack@suse.cz, Matthew Wilcox <willy@infradead.org>,
        benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, hpa@zytor.com,
        Will Deacon <will.deacon@arm.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com,
        npiggin@gmail.com, bsingharora@gmail.com,
        Tim Chen <tim.c.chen@linux.intel.com>,
        linuxppc-dev@lists.ozlabs.org, x86@kernel.org, lkp@01.org
Subject: Re: [mm] b1f0502d04: INFO:trying_to_register_non-static_key
In-Reply-To: <792c0f75-7e7f-cd81-44ae-4205f6e4affc@linux.vnet.ibm.com>
Message-ID: <alpine.DEB.2.20.1803251510040.80485@chino.kir.corp.google.com>
References: <20180317075119.u6yuem2bhxvggbz3@inn> <792c0f75-7e7f-cd81-44ae-4205f6e4affc@linux.vnet.ibm.com>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, 21 Mar 2018, Laurent Dufour wrote:

> I found the root cause of this lockdep warning.
> 
> In mmap_region(), unmap_region() may be called while vma_link() has not been
> called. This happens during the error path if call_mmap() failed.
> 
> The only to fix that particular case is to call
> seqcount_init(&vma->vm_sequence) when initializing the vma in mmap_region().
> 

Ack, although that would require a fixup to dup_mmap() as well.