From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2AC941A680D; Mon, 23 Mar 2026 14:18:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774275490; cv=none; b=EDcWIDCLG3wStHBisBXlZGBqhPsGNvyn984YbLSIy/XLhmjzbABptEtGs2Y0HQFcFZmvWQ3PqxT0er05JJBDZIUTzcC1A5BXmmgrHK3MTEhbkBMpIDHUbwZy5IJTALW19MD3E/vQJXB7HihAitwYq5PirQJdvtN3K6h9kADdO8Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774275490; c=relaxed/simple; bh=EKde+lfNBBK0wGsqZV2V2ZUpGxcxVvThQ6MHJtfk8OA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=r9UeQ19KK557CDnijrOZMtkF7cp1h3uEyNWIBhJdWJlJi9RjvVJMR0+Xd54QbFYs/mOjicD7gG5dzA/PKRnWm3r4JVqy8kOo5lVMggxgUn72F3RIT4arEnf11PdgKG6vPIeYjPGtEKo7IQ6ICfokgDAisRrX38I+peNiU6njomI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=S73L5aPc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="S73L5aPc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F88CC4CEF7; Mon, 23 Mar 2026 14:18:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774275490; bh=EKde+lfNBBK0wGsqZV2V2ZUpGxcxVvThQ6MHJtfk8OA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S73L5aPcBcuO+31BVGSrcoMLGZNM6HwnIvsLffceAacw4jOrw33C3SVgZjsJ+uTCH OlSGA2XSlUwRtWTNXrQ0VXrotb10UDY7Cl6SCKcGthh7Fyc3WR0G4EU6lH8cg9Z4Ir oNOk1FduL+7a/+oeHEGVGft4pGongJEGQe5pSHo0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexander Potapenko , Marco Elver , Andrey Konovalov , Andrey Ryabinin , Dmitry Vyukov , Ernesto Martinez Garcia , Kees Cook , Andrew Morton Subject: [PATCH 6.12 120/460] mm/kfence: disable KFENCE upon KASAN HW tags enablement Date: Mon, 23 Mar 2026 14:41:56 +0100 Message-ID: <20260323134529.576209103@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134526.647552166@linuxfoundation.org> References: <20260323134526.647552166@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Potapenko commit 09833d99db36d74456a4d13eb29c32d56ff8f2b6 upstream. KFENCE does not currently support KASAN hardware tags. As a result, the two features are incompatible when enabled simultaneously. Given that MTE provides deterministic protection and KFENCE is a sampling-based debugging tool, prioritize the stronger hardware protections. Disable KFENCE initialization and free the pre-allocated pool if KASAN hardware tags are detected to ensure the system maintains the security guarantees provided by MTE. Link: https://lkml.kernel.org/r/20260213095410.1862978-1-glider@google.com Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") Signed-off-by: Alexander Potapenko Suggested-by: Marco Elver Reviewed-by: Marco Elver Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Ernesto Martinez Garcia Cc: Greg KH Cc: Kees Cook Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/kfence/core.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -881,6 +882,20 @@ void __init kfence_alloc_pool_and_metada return; /* + * If KASAN hardware tags are enabled, disable KFENCE, because it + * does not support MTE yet. + */ + if (kasan_hw_tags_enabled()) { + pr_info("disabled as KASAN HW tags are enabled\n"); + if (__kfence_pool) { + memblock_free(__kfence_pool, KFENCE_POOL_SIZE); + __kfence_pool = NULL; + } + kfence_sample_interval = 0; + return; + } + + /* * If the pool has already been initialized by arch, there is no need to * re-allocate the memory pool. */