From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19D35C77B75 for ; Mon, 22 May 2023 19:44:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235214AbjEVTo0 (ORCPT ); Mon, 22 May 2023 15:44:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231837AbjEVToZ (ORCPT ); Mon, 22 May 2023 15:44:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACBB7A3 for ; Mon, 22 May 2023 12:44:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4375E621A1 for ; Mon, 22 May 2023 19:44:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 630D9C433D2; Mon, 22 May 2023 19:44:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684784663; bh=YJ2kbR/inwrBntwznegIodxruhy2OqKzgL6IGTufTe0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ka0yUGD+ukW1+U2fZ7q/u9bwRNiLEvT/fDWB6zT19oPa8oahM4rRArLNG7/Zvud9X KYl6lUelyuuo+2Zyd64DC6ZFG85Jg1lzV4N3aulW3hLPX6a7gnc8jzpoh+UxybMifx c1ns/ovUChhEG50Y6+vOmdpf1jEssesqTCsZB/AM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Steven Rostedt , Yafang , Masami Hiramatsu , Jiri Olsa , Hao Luo , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.3 117/364] bpf: Add preempt_count_{sub,add} into btf id deny list Date: Mon, 22 May 2023 20:07:02 +0100 Message-Id: <20230522190415.712290637@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190412.801391872@linuxfoundation.org> References: <20230522190412.801391872@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yafang [ Upstream commit c11bd046485d7bf1ca200db0e7d0bdc4bafdd395 ] The recursion check in __bpf_prog_enter* and __bpf_prog_exit* leave preempt_count_{sub,add} unprotected. When attaching trampoline to them we get panic as follows, [ 867.843050] BUG: TASK stack guard page was hit at 0000000009d325cf (stack is 0000000046a46a15..00000000537e7b28) [ 867.843064] stack guard page: 0000 [#1] PREEMPT SMP NOPTI [ 867.843067] CPU: 8 PID: 11009 Comm: trace Kdump: loaded Not tainted 6.2.0+ #4 [ 867.843100] Call Trace: [ 867.843101] [ 867.843104] asm_exc_int3+0x3a/0x40 [ 867.843108] RIP: 0010:preempt_count_sub+0x1/0xa0 [ 867.843135] __bpf_prog_enter_recur+0x17/0x90 [ 867.843148] bpf_trampoline_6442468108_0+0x2e/0x1000 [ 867.843154] ? preempt_count_sub+0x1/0xa0 [ 867.843157] preempt_count_sub+0x5/0xa0 [ 867.843159] ? migrate_enable+0xac/0xf0 [ 867.843164] __bpf_prog_exit_recur+0x2d/0x40 [ 867.843168] bpf_trampoline_6442468108_0+0x55/0x1000 ... [ 867.843788] preempt_count_sub+0x5/0xa0 [ 867.843793] ? migrate_enable+0xac/0xf0 [ 867.843829] __bpf_prog_exit_recur+0x2d/0x40 [ 867.843837] BUG: IRQ stack guard page was hit at 0000000099bd8228 (stack is 00000000b23e2bc4..000000006d95af35) [ 867.843841] BUG: IRQ stack guard page was hit at 000000005ae07924 (stack is 00000000ffd69623..0000000014eb594c) [ 867.843843] BUG: IRQ stack guard page was hit at 00000000028320f0 (stack is 00000000034b6438..0000000078d1bcec) [ 867.843842] bpf_trampoline_6442468108_0+0x55/0x1000 ... That is because in __bpf_prog_exit_recur, the preempt_count_{sub,add} are called after prog->active is decreased. Fixing this by adding these two functions into btf ids deny list. Suggested-by: Steven Rostedt Signed-off-by: Yafang Cc: Masami Hiramatsu Cc: Steven Rostedt Cc: Jiri Olsa Acked-by: Hao Luo Link: https://lore.kernel.org/r/20230413025248.79764-1-laoar.shao@gmail.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 64600acbb4e76..f4b267082cbf9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -17579,6 +17579,10 @@ BTF_ID(func, migrate_enable) #if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU BTF_ID(func, rcu_read_unlock_strict) #endif +#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE) +BTF_ID(func, preempt_count_add) +BTF_ID(func, preempt_count_sub) +#endif BTF_SET_END(btf_id_deny) static bool can_be_sleepable(struct bpf_prog *prog) -- 2.39.2