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 DED0A185924; Fri, 15 Nov 2024 06:51:41 +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=1731653502; cv=none; b=me75CyFLKcIhiRboKH7GaAeBf5eyt6sF3nrv/fLlJ/m70GgINdWif1yK6la1UyLQ5YvYnvatxaLIk5ZEVQ7peTC9CqhV3zmnIcGTD1+Zzj3uTDsMjHzPcapK6SNeJbvonMVRMkH7Rgx7Nrk94GBiQRoiSV3OLHT4swkkOdzzejk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731653502; c=relaxed/simple; bh=kgYwg87ZauiUbAyDrxgDO4Uy3EkMvxU+7TlymGOYEyM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GFa0cUiOM69vCcNzwteHA75fY+Gafj1r1TtUtK1aJThgQh0dYsBiwueMzFVWawFCus9R0YTP2YBdDQuHmPiFXV27C3310DEMQIq8EaECBg1FfSJ15qwSJ83xBoU8imAXvXuBigQD53m9OCQ2d+++mqvgLqOz200l9zDCb08w6Dw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JLL2MCHA; 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="JLL2MCHA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2E28C4CECF; Fri, 15 Nov 2024 06:51:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731653501; bh=kgYwg87ZauiUbAyDrxgDO4Uy3EkMvxU+7TlymGOYEyM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JLL2MCHAvjdggnwpCE+OLWCwA1OOXKS21xYW6vzDeA6LJgGXwleX1UqK+VtOiMeN+ C6+eRA+J9YrKNL2j9FCcnYwAgOYVm6B/N7HVWZzcGptelZmafbvVXKe3gbbRguk1fd iyv71fNRTDAsZH/zPObv/fDr+5m4jOb7IXAemVTo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qun-Wei Lin , David Rientjes , Vlastimil Babka Subject: [PATCH 6.6 41/48] mm: krealloc: Fix MTE false alarm in __do_krealloc Date: Fri, 15 Nov 2024 07:38:30 +0100 Message-ID: <20241115063724.445520202@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241115063722.962047137@linuxfoundation.org> References: <20241115063722.962047137@linuxfoundation.org> User-Agent: quilt/0.67 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qun-Wei Lin commit 704573851b51808b45dae2d62059d1d8189138a2 upstream. This patch addresses an issue introduced by commit 1a83a716ec233 ("mm: krealloc: consider spare memory for __GFP_ZERO") which causes MTE (Memory Tagging Extension) to falsely report a slab-out-of-bounds error. The problem occurs when zeroing out spare memory in __do_krealloc. The original code only considered software-based KASAN and did not account for MTE. It does not reset the KASAN tag before calling memset, leading to a mismatch between the pointer tag and the memory tag, resulting in a false positive. Example of the error: ================================================================== swapper/0: BUG: KASAN: slab-out-of-bounds in __memset+0x84/0x188 swapper/0: Write at addr f4ffff8005f0fdf0 by task swapper/0/1 swapper/0: Pointer tag: [f4], memory tag: [fe] swapper/0: swapper/0: CPU: 4 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12. swapper/0: Hardware name: MT6991(ENG) (DT) swapper/0: Call trace: swapper/0: dump_backtrace+0xfc/0x17c swapper/0: show_stack+0x18/0x28 swapper/0: dump_stack_lvl+0x40/0xa0 swapper/0: print_report+0x1b8/0x71c swapper/0: kasan_report+0xec/0x14c swapper/0: __do_kernel_fault+0x60/0x29c swapper/0: do_bad_area+0x30/0xdc swapper/0: do_tag_check_fault+0x20/0x34 swapper/0: do_mem_abort+0x58/0x104 swapper/0: el1_abort+0x3c/0x5c swapper/0: el1h_64_sync_handler+0x80/0xcc swapper/0: el1h_64_sync+0x68/0x6c swapper/0: __memset+0x84/0x188 swapper/0: btf_populate_kfunc_set+0x280/0x3d8 swapper/0: __register_btf_kfunc_id_set+0x43c/0x468 swapper/0: register_btf_kfunc_id_set+0x48/0x60 swapper/0: register_nf_nat_bpf+0x1c/0x40 swapper/0: nf_nat_init+0xc0/0x128 swapper/0: do_one_initcall+0x184/0x464 swapper/0: do_initcall_level+0xdc/0x1b0 swapper/0: do_initcalls+0x70/0xc0 swapper/0: do_basic_setup+0x1c/0x28 swapper/0: kernel_init_freeable+0x144/0x1b8 swapper/0: kernel_init+0x20/0x1a8 swapper/0: ret_from_fork+0x10/0x20 ================================================================== Fixes: 1a83a716ec233 ("mm: krealloc: consider spare memory for __GFP_ZERO") Signed-off-by: Qun-Wei Lin Acked-by: David Rientjes Signed-off-by: Vlastimil Babka Signed-off-by: Greg Kroah-Hartman --- mm/slab_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1391,7 +1391,7 @@ __do_krealloc(const void *p, size_t new_ /* Zero out spare memory. */ if (want_init_on_alloc(flags)) { kasan_disable_current(); - memset((void *)p + new_size, 0, ks - new_size); + memset(kasan_reset_tag(p) + new_size, 0, ks - new_size); kasan_enable_current(); }