On 7 Mar 2023, at 22:14, Chuck Lever III wrote:
>> On Mar 3, 2023, at 4:08 PM, Benjamin Coddington <bcodding@xxxxxxxxxx> wrote:
>>
>> Fix a race where kthread_stop() may prevent the threadfn from ever getting
>> called. If that happens the svc_rqst will not be cleaned up.
>>
>> Fixes: ed6473ddc704 ("NFSv4: Fix callback server shutdown")
>> Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
>> ---
>> net/sunrpc/svc.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
>> index 1fd3f5e57285..fea7ce8fba14 100644
>> --- a/net/sunrpc/svc.c
>> +++ b/net/sunrpc/svc.c
>> @@ -798,6 +798,7 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
>> static int
>> svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
>> {
>> + struct svc_rqst *rqstp;
>> struct task_struct *task;
>> unsigned int state = serv->sv_nrthreads-1;
>>
>> @@ -806,7 +807,10 @@ svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
>> task = choose_victim(serv, pool, &state);
>> if (task == NULL)
>> break;
>> - kthread_stop(task);
>> + rqstp = kthread_data(task);
>> + /* Did we lose a race to svo_function threadfn? */
>> + if (kthread_stop(task) == -EINTR)
>> + svc_exit_thread(rqstp);
>> nrservs++;
>> } while (nrservs < 0);
>> return 0;
>> --
>> 2.31.1
>>
>
> Seems sensible, applied. Is there a bugzilla link that should be included?
No, the issue was found in a private environment.
Ben
