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From: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
To: den@openvz.org
Cc: devel@openvz.org
Subject: [Devel] [PATCH hci-8.1 v6 07/12] dm-ploop: take bat_lock around md page lookup in ploop_llseek_hole()
Date: Tue, 13 Oct 2026 13:15:59 +0200	[thread overview]
Message-ID: <20261013111604.142989-8-alexander.ivanov@virtuozzo.com> (raw)
In-Reply-To: <20261013111604.142989-1-alexander.ivanov@virtuozzo.com>

ploop_llseek_hole() walks the md pages tree without any lock, while
resize inserts new md pages into it in ploop_add_md_pages(). A lookup
racing with rb-tree rebalancing may follow a stale pointer or miss the
page and return -EINVAL.

https://virtuozzo.atlassian.net/browse/VSTOR-148171
Feature: dm-ploop: ploop target driver

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
 drivers/md/dm-ploop-map.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 92ceadf41b42..691284a239df 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -2772,7 +2772,11 @@ loff_t ploop_llseek_hole(struct dm_target *ti, loff_t offset, int whence)
 	while (clu < READ_ONCE(ploop->nr_bat_entries)) {
 		if (id != ploop_bat_clu_to_page_nr(clu)) {
 			id = ploop_bat_clu_to_page_nr(clu);
+
+			spin_lock_irq(&ploop->bat_lock);
 			md = ploop_md_page_find(ploop, id);
+			spin_unlock_irq(&ploop->bat_lock);
+
 			if (!md)
 				return -EINVAL;
 		}
-- 
2.53.0

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  parent reply	other threads:[~2026-10-13 11:17 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-13 11:15 [Devel] [PATCH hci-8.1 v6 00/12] dm-ploop: give back unused tail of top delta on suspend Alexander Ivanov
2026-10-13 11:15 ` [Devel] [PATCH hci-8.1 v6 01/12] dm-ploop: fix u32 overflow of the delta BAT byte size Alexander Ivanov
2026-10-13 11:23   ` no-reply
2026-10-13 11:15 ` [Devel] [PATCH hci-8.1 v6 02/12] dm-ploop: fix lost wakeup in ploop_allocator() Alexander Ivanov
2026-10-13 11:21   ` no-reply
2026-10-13 11:15 ` [Devel] [PATCH hci-8.1 v6 03/12] dm-ploop: reject a delta header whose BAT does not cover the target Alexander Ivanov
2026-10-13 11:22   ` no-reply
2026-10-13 11:15 ` [Devel] [PATCH hci-8.1 v6 04/12] dm-ploop: reject empty deltas Alexander Ivanov
2026-10-13 11:24   ` no-reply
2026-10-13 11:15 ` [Devel] [PATCH hci-8.1 v6 05/12] dm-ploop: set delta is_raw before applying its mappings Alexander Ivanov
2026-10-13 11:24   ` no-reply
2026-10-13 11:15 ` [Devel] [PATCH hci-8.1 v6 06/12] dm-ploop: factor out ploop_read_delta() from ploop_add_delta() Alexander Ivanov
2026-10-13 11:25   ` no-reply
2026-10-13 11:15 ` Alexander Ivanov [this message]
2026-10-13 11:26   ` [Devel] [PATCH hci-8.1 v6 07/12] dm-ploop: take bat_lock around md page lookup in ploop_llseek_hole() no-reply
2026-10-13 11:16 ` [Devel] [PATCH hci-8.1 v6 08/12] dm-ploop: use wake_up() for inflight_md_wq and dispatcher_wq_prealloc Alexander Ivanov
2026-10-13 11:26   ` no-reply
2026-10-13 11:16 ` [Devel] [PATCH hci-8.1 v6 09/12] dm-ploop: fix use-after-free on the last inflight_md decrement Alexander Ivanov
2026-10-13 11:30   ` no-reply
2026-10-13 11:16 ` [Devel] [PATCH hci-8.1 v6 10/12] dm-ploop: fix flip_upper_deltas racing with resume Alexander Ivanov
2026-10-13 11:28   ` no-reply
2026-10-13 11:16 ` [Devel] [PATCH hci-8.1 v6 11/12] dm-ploop: reload metadata on resume Alexander Ivanov
2026-10-13 11:35   ` no-reply
2026-10-13 12:46     ` Alexander Ivanov
2026-10-13 11:16 ` [Devel] [PATCH hci-8.1 v6 12/12] dm-ploop: truncate unused tail of top delta on suspend Alexander Ivanov
2026-10-13 11:38   ` no-reply
2026-10-13 12:53     ` Alexander Ivanov

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