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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 73052C44500 for ; Mon, 29 Jun 2026 07:28:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=QiCw3hdqkp26lcFPcOaRRc3k9IbcuyG0S5yJNMolRL8=; b=E5e1b2HuIMsowC aQXuVpFNb3wGOHeHi85Wc5YSlzaiwod7dEsCFDMUnREhKYJ94xjerdJtfZbvpsrH10jLF15dSMTp1 3ZpWtwXKhWSedMqkWDpSkorGtucr0I+3opAr/coKkgrzEGF64MI/q0oObKcb/5RbIZNEHNf2rX9AS 2DGS9f4uE9d40vqJZHHZgkDu07VIaEkGPhIAWhAB4AVFvzaHOzHxFYPSujNQ6f065ixKKPR4gpxDf kVkTOEsxtUNgYO2XIGMjHSUgdH3QRqGPwK1c5KCgBR4wzliyW1a9x/oF8y9/4N8iNYJ/AhfoBWzhH qVR0GqlIzuDoTADnukDg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1we6Px-0000000DtIv-2nUu; Mon, 29 Jun 2026 07:28:33 +0000 Received: from out30-119.freemail.mail.aliyun.com ([115.124.30.119]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1we6Pv-0000000DtGv-1Nku for linux-riscv@lists.infradead.org; Mon, 29 Jun 2026 07:28:32 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1782718109; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=m8pnWfAyIRGdD3GPjP0E4M3+tZYcgxHxMKpoX0zv1+E=; b=XNG1i9SaaYehHww1yZyh4ZPEBj/r+lza2/UYNvqY3iox7m9p4FqP+joG0REy0Xt53+E04LGmngGDsYjxeVNnldrncZomcuihYmrCIBx3GCbLZjgEsQUxbgxpFuc5tvVGKWa1uCtUdNiAa4dZQ4vJW7dsdrP2LZchsV4Td0oguIw= X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam011083073210;MF=wanghan@linux.alibaba.com;NM=1;PH=DS;RN=34;SR=0;TI=SMTPD_---0X5oo1Kd_1782718104; Received: from wanghan-Workstation..(mailfrom:wanghan@linux.alibaba.com fp:SMTPD_---0X5oo1Kd_1782718104 cluster:ay36) by smtp.aliyun-inc.com; Mon, 29 Jun 2026 15:28:27 +0800 From: Wang Han To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Alexandre Ghiti , linux-riscv@lists.infradead.org, Oleg Nesterov , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Shuah Khan , oliver.yang@linux.alibaba.com, xueshuai@linux.alibaba.com, zhuo.song@linux.alibaba.com, jkchen@linux.alibaba.com, Marcos Paulo de Souza , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, live-patching@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v4 RESEND 2/7] riscv: stacktrace: disable KASAN and KCOV instrumentation for stacktrace.o Date: Mon, 29 Jun 2026 15:27:08 +0800 Message-ID: <20260629072713.3273743-3-wanghan@linux.alibaba.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260629072713.3273743-1-wanghan@linux.alibaba.com> References: <20260629072713.3273743-1-wanghan@linux.alibaba.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260629_002831_551323_6F2A7195 X-CRM114-Status: UNSURE ( 8.83 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org KASAN records stack traces for every alloc/free, which means it walks the unwinder very frequently. Instrumenting the stack trace collection code itself adds substantial overhead and makes the traces themselves noisier. KCOV instruments every basic-block edge. The unwinder is a hot path, especially with KASAN enabled, so KCOV instrumentation has the same kind of cost and noise problem here. Mark stacktrace.o as not KASAN- or KCOV-instrumented, matching the x86 treatment of its stack unwinding code. RISC-V keeps the relevant unwinder code in stacktrace.o, so a single translation-unit annotation covers the equivalent scope. This is a prerequisite preference for the upcoming reliable unwinder, but the change is valid on its own. Signed-off-by: Wang Han --- arch/riscv/kernel/Makefile | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index cabb99cadfb6..c565a72a36f3 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -44,6 +44,12 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_sbi_ecall.o = $(CC_FLAGS_FTRACE) endif +# When KASAN is enabled, a stack trace is recorded for every alloc/free, which +# can significantly impact performance. Avoid instrumenting the stack trace +# collection code to minimize this impact. +KASAN_SANITIZE_stacktrace.o := n +KCOV_INSTRUMENT_stacktrace.o := n + always-$(KBUILD_BUILTIN) += vmlinux.lds obj-y += head.o -- 2.43.0 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv