Re: [PATCH 5.15 00/23] 5.15.160-rc1 review

Jon Hunter
2024-05-29T08:59:47Z

On 29/05/2024 00:42, NeilBrown wrote:
> On Wed, 29 May 2024, NeilBrown wrote:
>>
>> We probably just need to add "| TASK_FREEZABLE" in one or two places.
>> I'll post a patch for testing in a little while.
>
> There is no TASK_FREEZABLE before v6.1.
> This isn't due to a missed backport. It is simply because of differences
> in the freezer in older kernels.
>
> Please test this patch.
>
> Thanks,
> NeilBrown
>
> From 416bd6ae9a598e64931d34b76aa58f39b11841cd Mon Sep 17 00:00:00 2001
> From: NeilBrown <neilb@suse.de>
> Date: Wed, 29 May 2024 09:38:22 +1000
> Subject: [PATCH] sunrpc: exclude from freezer when waiting for requests:
>
> Prior to v6.1, the freezer will only wake a kernel thread from an
> uninterruptible sleep. Since we changed svc_get_next_xprt() to use and
> IDLE sleep the freezer cannot wake it. we need to tell the freezer to
> ignore it instead.
>
> Fixes: 9b8a8e5e8129 ("nfsd: don't allow nfsd threads to be signalled.")
> Signed-off-by: NeilBrown <neilb@suse.de>
> ---
> net/sunrpc/svc_xprt.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index b19592673eef..12e9293bd12b 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -764,10 +764,12 @@ static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
> clear_bit(RQ_BUSY, &rqstp->rq_flags);
> smp_mb__after_atomic();
>
> + freezer_do_not_count();
> if (likely(rqst_should_sleep(rqstp)))
> time_left = schedule_timeout(timeout);
> else
> __set_current_state(TASK_RUNNING);
> + freezer_count();
>
> try_to_freeze();
>

Thanks. I gave this a try on top of v5.15.160-rc1, but I am still seeing
the following and the board hangs ...

Freezing of tasks failed after 20.004 seconds (1 tasks refusing to freeze, wq_busy=0):

So unfortunately this does not fix it :-(

Jon

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nvpublic