From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 498CB4FE2F2; Wed, 30 Sep 2026 16:47:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790786865; cv=none; b=p7yr/3yPYaRy4l7pgELP4VHTmYS+5gknSVPugyAwcAtsCwfFohYFGDmbA8rA86+HlgK/PAnB/LDOFdCpuxUQZkwFwTGUzdfOPlr114vfbHAJ5lRxXjbOULAXS/uC11GA3yEvOOHVZJjino2vOfbFaxuHj1FfGZ9XkYCkjeHkgGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790786865; c=relaxed/simple; bh=wPQnbyBZmuuEJGeFdBVIhjbzsEZ521GA31blD7pEzgY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Y2b9EpovvANWyYOOAuw/b41fdJHlbgwsfE9hlwYEi4zCLcKhfD7BHfeaBdDxmUSoFlBmVmmq2hKA7ID5QtQzAL2ANHV9YBp7HTsr4t4HC/gOwDE6eQyu0rMkZvs4klb8ZUK2oBUIgmbmD9UpHGRVdQvml5ZapSd/MKkhpGx19tQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qeSeylRv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qeSeylRv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A41351F000FF; Wed, 30 Sep 2026 16:47:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790786864; bh=gaJzHnh/YhKHauU+1GR+zldO8zapfbcW92bTBIkCCDU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qeSeylRvazBPWP/DXvUtqeKirwLMfNMs2HH61mrTCU+QZXJi2c55+WXbGsxqoZVDi lHUxbfuCWZLMo/hnEARAZxXwwqlwE1WDN81MnZA7i8JrY6qVzqyRWCnqgoJChtXQ92 zEZ6u4YAlOCuI1ylPGN+L9oy8BVJvQgMlReO8yP0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Claudio Imbrenda , Sasha Levin Subject: [PATCH 7.2 012/457] KVM: s390: Fix race in _destroy_pages_crste() Date: Wed, 30 Sep 2026 17:21:57 +0200 Message-ID: <20260930152346.296599661@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152346.024115587@linuxfoundation.org> References: <20260930152346.024115587@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Claudio Imbrenda [ Upstream commit 4ca00a9154f998116fba9a32cce5bd938d228065 ] Use READ_ONCE() in _destroy_pages_crste() to read the crste, avoid dereferencing the pointer multiple times. Fixes: a2c17f9270cc ("KVM: s390: New gmap code") Signed-off-by: Claudio Imbrenda Message-ID: <20260828115439.145885-9-imbrenda@linux.ibm.com> Signed-off-by: Sasha Levin --- arch/s390/kvm/gmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/gmap.c b/arch/s390/kvm/gmap.c index 8abb4f55b306b..f11d4ecaef7be 100644 --- a/arch/s390/kvm/gmap.c +++ b/arch/s390/kvm/gmap.c @@ -991,11 +991,13 @@ static long _destroy_pages_pte(union pte *ptep, gfn_t gfn, gfn_t next, struct da static long _destroy_pages_crste(union crste *crstep, gfn_t gfn, gfn_t next, struct dat_walk *walk) { phys_addr_t origin, cur, end; + union crste crste; - if (!crstep->h.fc || !crstep->s.fc1.pr) + crste = READ_ONCE(*crstep); + if (!crste.h.fc || !crste.s.fc1.pr) return 0; - origin = crste_origin_large(*crstep); + origin = crste_origin_large(crste); cur = ((max(gfn, walk->start) - gfn) << PAGE_SHIFT) + origin; end = ((min(next, walk->end) - gfn) << PAGE_SHIFT) + origin; for ( ; cur < end; cur += PAGE_SIZE) -- 2.53.0