Re: [PATCH] vhost/crypto: fix segfault

[Radu Nicolau <radu.nicolau@intel.com>]

On 29-Jun-26 9:18 AM, Maxime Coquelin wrote:
> On Fri, Jun 26, 2026 at 10:50 AM Radu Nicolau <radu.nicolau@intel.com> wrote:
>>
>> On 25-Jun-26 1:44 PM, David Marchand wrote:
>>> On Wed, 24 Jun 2026 at 16:21, Radu Nicolau <radu.nicolau@intel.com> wrote:
>>>> Fix potential call with dev->mem uninitialized, one common usecase
>>>> example being running the autotest with more than one device.
>>>>
>>>> Fixes: 3bb595ecd682 ("vhost/crypto: add request handler")
>>>> Cc: stable@dpdk.org
>>>>
>>>> Signed-off-by: Radu Nicolau <radu.nicolau@intel.com>
>>>> ---
>>>>    lib/vhost/vhost_crypto.c | 4 ++++
>>>>    1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/lib/vhost/vhost_crypto.c b/lib/vhost/vhost_crypto.c
>>>> index 648e2d731b..3679eaca1e 100644
>>>> --- a/lib/vhost/vhost_crypto.c
>>>> +++ b/lib/vhost/vhost_crypto.c
>>>> @@ -1512,6 +1512,10 @@ vhost_crypto_process_one_req(struct vhost_crypto *vcrypto,
>>>>                   VC_LOG_ERR("Invalid descriptor");
>>>>                   return -1;
>>>>           }
>>>> +       if (unlikely((vc_req->dev->mem) == NULL)) {
>>> (Unneeded extra ())
>>>
>>> It sounds to me that some initialisation failed, or processing happens
>>> without waiting initialisation finished.
>> Indeed calling this function with dev->mem uninitialized is caused by
>> some init/deinit state bug, but I still think we should keep this check
>> in for added safety.
>>
>> I will follow up with a v2 to remove the redundant () and also I will
>> look into fixing the root cause.
> Or maybe this crypto backend is lacking proper protection between
> control and data paths?
> If dev->mem is reset to NULL asynchrously by the control path without
> proper locking, then
> the above fix is not enough. For example, the above check could pass
> and dev->mem be
> reset right after.
100% there is a deeper root cause for this segfault and I'm working to 
find it, but it may take a while. That's why I propose this as a stop 
gap fix, it adds an extra check but of course it doesn't remove the root 
cause.