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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 E2638C433DF for ; Tue, 2 Jun 2020 05:30:37 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9A4EB206A2 for ; Tue, 2 Jun 2020 05:30:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9A4EB206A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49bgcC4kGzzDqXJ for ; Tue, 2 Jun 2020 15:30:35 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (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 lists.ozlabs.org (Postfix) with ESMTPS id 49bgVd0qqhzDqQm for ; Tue, 2 Jun 2020 15:25:45 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 49bgVc0ql9z9sSg; Tue, 2 Jun 2020 15:25:43 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 2f26ed1764b42a8c40d9c48441c73a70d805decf In-Reply-To: <20200529061446.2773-1-dja@axtens.net> To: Daniel Axtens , linuxppc-dev@lists.ozlabs.org, npiggin@gmail.com From: Michael Ellerman Subject: Re: [PATCH] powerpc/64/syscall: Disable sanitisers for C syscall entry/exit code Message-Id: <49bgVc0ql9z9sSg@ozlabs.org> Date: Tue, 2 Jun 2020 15:25:43 +1000 (AEST) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ajd@linux.ibm.com, Daniel Axtens Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, 2020-05-29 at 06:14:46 UTC, Daniel Axtens wrote: > syzkaller is picking up a bunch of crashes that look like this: > > Unrecoverable exception 380 at c00000000037ed60 (msr=8000000000001031) > Oops: Unrecoverable exception, sig: 6 [#1] > LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries > Modules linked in: > CPU: 0 PID: 874 Comm: syz-executor.0 Not tainted 5.7.0-rc7-syzkaller-00016-gb0c3ba31be3e #0 > NIP: c00000000037ed60 LR: c00000000004bac8 CTR: c000000000030990 > REGS: c0000000555a7230 TRAP: 0380 Not tainted (5.7.0-rc7-syzkaller-00016-gb0c3ba31be3e) > MSR: 8000000000001031 CR: 48222882 XER: 20000000 > CFAR: c00000000004bac4 IRQMASK: 0 > GPR00: c00000000004bb68 c0000000555a74c0 c0000000024b3500 0000000000000005 > GPR04: 0000000000000000 0000000000000000 c00000000004bb88 c008000000910000 > GPR08: 00000000000b0000 c00000000004bac8 0000000000016000 c000000002503500 > GPR12: c000000000030990 c000000003190000 00000000106a5898 00000000106a0000 > GPR16: 00000000106a5890 c000000007a92000 c000000008180e00 c000000007a8f700 > GPR20: c000000007a904b0 0000000010110000 c00000000259d318 5deadbeef0000100 > GPR24: 5deadbeef0000122 c000000078422700 c000000009ee88b8 c000000078422778 > GPR28: 0000000000000001 800000000280b033 0000000000000000 c0000000555a75a0 > NIP [c00000000037ed60] __sanitizer_cov_trace_pc+0x40/0x50 > LR [c00000000004bac8] interrupt_exit_kernel_prepare+0x118/0x310 > Call Trace: > [c0000000555a74c0] [c00000000004bb68] interrupt_exit_kernel_prepare+0x1b8/0x310 (unreliable) > [c0000000555a7530] [c00000000000f9a8] interrupt_return+0x118/0x1c0 > --- interrupt: 900 at __sanitizer_cov_trace_pc+0x0/0x50 > ...... > > That looks like the KCOV helper accessing memory that's not safe to > access in the interrupt handling context. > > Do not instrument the new syscall entry/exit code with KCOV, GCOV or > UBSAN. > > Cc: Nicholas Piggin > Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in C") > Signed-off-by: Daniel Axtens Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/2f26ed1764b42a8c40d9c48441c73a70d805decf cheers