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 X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D55F2C4338F for ; Thu, 12 Aug 2021 12:34:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A71EB60724 for ; Thu, 12 Aug 2021 12:34:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237050AbhHLMfQ (ORCPT ); Thu, 12 Aug 2021 08:35:16 -0400 Received: from smtp-relay-canonical-0.canonical.com ([185.125.188.120]:53704 "EHLO smtp-relay-canonical-0.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235563AbhHLMfP (ORCPT ); Thu, 12 Aug 2021 08:35:15 -0400 Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-0.canonical.com (Postfix) with ESMTPS id 7D2AA40C9C for ; Thu, 12 Aug 2021 12:34:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1628771689; bh=fXksQPpDuH6T7x4BT558ZGGix2k0x0Rejn/yRv3oga8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=IIhG2uAXgGCTKLClJVk//cM5thqXj+TdlzM2/jqpIYBYA1N791/3SJ2bnhMEN/zbW tjvF1ja4XkFs8xhGqhVwHwKt1t9WREiv7gTJaurgDysK1HueEF9TCAa3uDnU1b3kG2 f0d2M6EV5DxSVFoR3Y0fdFV9B2BUmyLnGbjaUhgEdbfYljrCcltdx/+3ZjhULjo5hD oTVVLSj+T+/9YG0YU8bHXBuxGJVHvzi6c0vLJxicDswgdgn4lF3zI84JvV/w1ELHs0 PCgB1yqQxOt8H0Zq+ZvmKkYMhCOLANJPKGB8s6kIXg6dylq9R33KKQCEe19fWFtYAY HSHE0fPBmsRJA== Received: by mail-wr1-f72.google.com with SMTP id d12-20020a056000186cb02901548bff164dso1770008wri.18 for ; Thu, 12 Aug 2021 05:34:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=fXksQPpDuH6T7x4BT558ZGGix2k0x0Rejn/yRv3oga8=; b=ZSmUEL6r/+/H3//BTeQ7zpRDTTcjNlzl95toB/UY4fup8Xbj5TlT0PhVOT9kZJRwTn KqVO3zWV1xUs1nyYg2z6riijNNJuXM08TmhhSmUcGf5ckQXtoH7vcSQnQLp1al/wAYfD aZBEzWCQRjcsQvOERp/dU9nQBnK3YM8HzoJ21WgT7MVF0GW8c1bHcxVluup0RJGUidz4 buMCqfsYN7QY5P4YWDq30cuJKz6bjL/Jkra6LHvMG6hVNLp1/e4K+VVUx+LixLZfQFH9 KXE9lhL7YmGvcp6FiBSeNyKzVZpb7gkypnhLyHOvYbOR3ZsT18S0QZutTvnfzZca+Ee7 pVmA== X-Gm-Message-State: AOAM532E5/lKIesKOIM5mnsVpGn91hUGb+npPb/dFzJcoDSbCLlFtpXr nTowjmeN+YWXlTb5IWN8nk1S//2P3FREtEi8+I+9KLj1CZG0MNl7l7o8YKGKwilgDm25o3ZdBIA lDdONPlqTuBbOfcU7H++hMxX+QDL2wQVOCPOUf8aVaQ== X-Received: by 2002:adf:f08e:: with SMTP id n14mr3655708wro.427.1628771688823; Thu, 12 Aug 2021 05:34:48 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyF/ZR5C1BtBNd4kJJCPmKateoDi+EtUFQPs23ytvlz7wdG1g2X3iPF4mV40XLyvZ9KL1CdDg== X-Received: by 2002:adf:f08e:: with SMTP id n14mr3655691wro.427.1628771688574; Thu, 12 Aug 2021 05:34:48 -0700 (PDT) Received: from localhost ([2a01:4b00:85fd:d700:1220:9591:5798:fefe]) by smtp.gmail.com with ESMTPSA id 129sm2646812wmz.26.2021.08.12.05.34.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Aug 2021 05:34:48 -0700 (PDT) From: Dimitri John Ledkov To: linux-kernel@vger.kernel.org Cc: Thadeu Lima de Souza Cascardo , Pierce Andjelkovic , Paul Walmsley , linux-riscv@lists.infradead.org Subject: [PATCH] RISC-V: prevent sbi_send_cpumask_ipi race with ftrace Date: Thu, 12 Aug 2021 13:34:33 +0100 Message-Id: <20210812123433.27871-1-dimitri.ledkov@canonical.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thadeu Lima de Souza Cascardo ftrace will patch instructions in sbi_send_cpumask_ipi, which is going to be used by flush_icache_range, leading to potential races and crashes like this: [ 0.000000] ftrace: allocating 38893 entries in 152 pages [ 0.000000] Oops - illegal instruction [#1] [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.11.0-1014-generic #14-Ubuntu [ 0.000000] epc: ffffffe00000920e ra : ffffffe000009384 sp : ffffffe001803d30 [ 0.000000] gp : ffffffe001a14240 tp : ffffffe00180f440 t0 : ffffffe07fe38000 [ 0.000000] t1 : ffffffe0019cd338 t2 : 0000000000000000 s0 : ffffffe001803d70 [ 0.000000] s1 : 0000000000000000 a0 : ffffffe0000095aa a1 : 0000000000000001 [ 0.000000] a2 : 0000000000000002 a3 : 0000000000000000 a4 : 0000000000000000 [ 0.000000] a5 : 0000000000000000 a6 : 0000000000000004 a7 : 0000000052464e43 [ 0.000000] s2 : 0000000000000002 s3 : 0000000000000001 s4 : 0000000000000000 [ 0.000000] s5 : 0000000000000000 s6 : 0000000000000000 s7 : 0000000000000000 [ 0.000000] s8 : ffffffe001a170c0 s9 : 0000000000000001 s10: 0000000000000001 [ 0.000000] s11: 00000000fffcc5d0 t3 : 0000000000000068 t4 : 000000000000000b [ 0.000000] t5 : ffffffe0019cd3e0 t6 : ffffffe001803cd8 [ 0.000000] status: 0000000200000100 badaddr: 000000000513f187 cause: 0000000000000002 [ 0.000000] ---[ end trace f67eb9af4d8d492b ]--- [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! [ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- Where ffffffe00000920e lies in the middle of sbi_send_cpumask_ipi. Reproduced on Unmatched board using Ubuntu kernels. See https://people.canonical.com/~xnox/lp1934548/ for sample images, kernels, debug symbols. BugLink: https://bugs.launchpad.net/bugs/1934548 Reported-by: Pierce Andjelkovic Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Dimitri John Ledkov cc: Paul Walmsley cc: linux-riscv@lists.infradead.org cc: stable@vger.kernel.org --- arch/riscv/kernel/sbi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 7402a417f38e..158199865c68 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -562,7 +562,7 @@ long sbi_get_mimpid(void) return __sbi_base_ecall(SBI_EXT_BASE_GET_MIMPID); } -static void sbi_send_cpumask_ipi(const struct cpumask *target) +static void notrace sbi_send_cpumask_ipi(const struct cpumask *target) { struct cpumask hartid_mask; -- 2.30.2