From: no-reply@sashiko.virtuozzo.com
To: Alexander Ivanov <alexander.ivanov@virtuozzo.com>, den@openvz.org
Cc: devel@openvz.org
Subject: Re: [Devel] [PATCH hci-8.1 v5 02/11] dm-ploop: fix lost wakeup in ploop_allocator()
Date: Tue, 13 Oct 2026 08:00:36 +0000 [thread overview]
Message-ID: <010701a1344714d7-802b9c3a-c31d-4a52-894c-8f337ef7ec66-000000@eu-central-1.amazonses.com> (raw)
In-Reply-To: <20261013075513.90618-3-alexander.ivanov@virtuozzo.com>
> ploop_allocator() checks prealloc_size and kthread_should_stop() before
> setting TASK_INTERRUPTIBLE. If ploop_req_prealloc() sets prealloc_size
> and calls wake_up_process() in between, the wakeup finds the task
> running and is lost, so the allocator goes to sleep with a pending
> preallocation request. Later requests for the same size return early
> without waking it up, so the request may stay pending forever and
> waiters on dispatcher_wq_prealloc hang. The same applies to
> kthread_stop().
>
> Set the task state before checking the conditions, as the canonical
> kthread loop does. set_current_state() implies a full barrier, which
> pairs with the one in try_to_wake_up().
>
> https://virtuozzo.atlassian.net/browse/VSTOR-148171
> Feature: dm-ploop: ploop target driver
>
> Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261013075513.90618-1-alexander.ivanov@virtuozzo.com?part=2
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next prev parent reply other threads:[~2026-10-13 8:01 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-13 7:55 [Devel] [PATCH hci-8.1 v5 00/11] dm-ploop: give back unused tail of top delta on suspend Alexander Ivanov
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 01/11] dm-ploop: fix u32 overflow of the delta BAT byte size Alexander Ivanov
2026-10-13 8:02 ` no-reply
2026-10-13 9:24 ` Alexander Ivanov
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 02/11] dm-ploop: fix lost wakeup in ploop_allocator() Alexander Ivanov
2026-10-13 8:00 ` no-reply [this message]
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 03/11] dm-ploop: reject a delta header whose BAT does not cover the target Alexander Ivanov
2026-10-13 8:01 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 04/11] dm-ploop: reject empty deltas Alexander Ivanov
2026-10-13 8:02 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 05/11] dm-ploop: set delta is_raw before applying its mappings Alexander Ivanov
2026-10-13 8:03 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 06/11] dm-ploop: factor out ploop_read_delta() from ploop_add_delta() Alexander Ivanov
2026-10-13 8:04 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 07/11] dm-ploop: take bat_lock around md page lookup in ploop_llseek_hole() Alexander Ivanov
2026-10-13 8:06 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 08/11] dm-ploop: use wake_up() for inflight_md_wq and dispatcher_wq_prealloc Alexander Ivanov
2026-10-13 8:04 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 09/11] dm-ploop: fix use-after-free on the last inflight_md decrement Alexander Ivanov
2026-10-13 8:11 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 10/11] dm-ploop: reload metadata on resume Alexander Ivanov
2026-10-13 8:16 ` no-reply
2026-10-13 7:55 ` [Devel] [PATCH hci-8.1 v5 11/11] dm-ploop: truncate unused tail of top delta on suspend Alexander Ivanov
2026-10-13 8:20 ` no-reply
2026-10-13 11:00 ` Alexander Ivanov
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