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From: Chris Li <chrisl@kernel.org>
Date: Thu, 21 Mar 2024 16:53:17 -0700
Subject: [PATCH] zswap: initialize entry->pool on same filled entry
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Message-Id: <20240321-zswap-fill-v1-1-b6180dbf7c27@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, 
 Yosry Ahmed <yosryahmed@google.com>, Nhat Pham <nphamcs@gmail.com>, 
 Johannes Weiner <hannes@cmpxchg.org>, 
 Chengming Zhou <zhouchengming@bytedance.com>, Chris Li <chrisl@kernel.org>

Current zswap will leave the entry->pool uninitialized if
the page is same  filled. The entry->pool pointer can
contain data written by previous usage.

Initialize entry->pool to zero for the same filled zswap entry.

Signed-off-by: Chris Li <chrisl@kernel.org>
---
Per Yosry's suggestion to split out this clean up
from the zxwap rb tree to xarray patch.

https://lore.kernel.org/all/ZemDuW25YxjqAjm-@google.com/
---
 mm/zswap.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/zswap.c b/mm/zswap.c
index b31c977f53e9..f04a75a36236 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1527,6 +1527,7 @@ bool zswap_store(struct folio *folio)
 			kunmap_local(src);
 			entry->length = 0;
 			entry->value = value;
+			entry->pool = 0;
 			atomic_inc(&zswap_same_filled_pages);
 			goto insert_entry;
 		}

---
base-commit: a824831a082f1d8f9b51a4c0598e633d38555fcf
change-id: 20240315-zswap-fill-f65f44574760

Best regards,
-- 
Chris Li <chrisl@kernel.org>