The patch titled
Subject: mm-zswap-fix-potential-memory-corruption-on-duplicate-store-v2
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-zswap-fix-potential-memory-corruption-on-duplicate-store-v2.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-fix-potential-memory-corruption-on-duplicate-store-v2.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Subject: mm-zswap-fix-potential-memory-corruption-on-duplicate-store-v2
Date: Mon, 25 Sep 2023 15:00:02 +0200
add a warning and a comment to the second duplicates check in
zswap_store() (Johannes).
Link: https://lkml.kernel.org/r/20230925130002.1929369-1-cerasuolodomenico@xxxxxxxxx
Fixes: 42c06a0e8ebe ("mm: kill frontswap")
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zswap.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/zswap.c~mm-zswap-fix-potential-memory-corruption-on-duplicate-store-v2
+++ a/mm/zswap.c
@@ -1346,7 +1346,14 @@ insert_entry:
/* map */
spin_lock(&tree->lock);
+ /*
+ * A duplicate entry should have been removed at the beginning of this
+ * function. Since the swap entry should be pinned, if a duplicate is
+ * found again here it means that something went wrong in the swap
+ * cache.
+ */
while (zswap_rb_insert(&tree->rbroot, entry, &dupentry) == -EEXIST) {
+ WARN_ON(1);
zswap_duplicate_entry++;
zswap_invalidate_entry(tree, dupentry);
}
_
Patches currently in -mm which might be from cerasuolodomenico@xxxxxxxxx are
mm-zswap-fix-potential-memory-corruption-on-duplicate-store.patch
mm-zswap-fix-potential-memory-corruption-on-duplicate-store-v2.patch
zswap-make-shrinking-memcg-aware.patch
