From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-98.freemail.mail.aliyun.com (out30-98.freemail.mail.aliyun.com [115.124.30.98]) (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 531353E6DD8; Wed, 8 Jul 2026 07:04:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.98 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783494310; cv=none; b=lwWG6HFUgqJDEzA44/9lHNAJ8rMjadZRHvtQjMqC/3P6eCsGazeXq0IK1EReubVaQ+fROxHemPGqso+6xGBS3V79WKkLuH6+LVRVWE6C1b3rjBiIXtZWZPhwZ+2uq48wgXcotKMUZEyctgEa5PNVHvMrYTnbCiIEh402P/ShwfE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783494310; c=relaxed/simple; bh=Kfrb3+5tYPOiLtvz4HJtKv6RKCL/qDqvGfR0DV4LxG4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Rfcs8RGURAXefMa4tLHfhjCfZMvU/USe4Q9FIWx5aykqchHhySf9DH1u5H3wqO8sm/jZ+zybsznFvm9rmGBXy98+XmvhHfgvMPv/AoewzB0wkVYAIBF93zIyMQQXaFJ4yo61wgjo2SQ7v7vBKRKfgEhZEsB98wfX1Xjx0F2opfE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=ldyH6F58; arc=none smtp.client-ip=115.124.30.98 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="ldyH6F58" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1783494285; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=VqOzBHcezIdJbCw9H20f4ApkMFhu+ojhnSlVxGo7tKM=; b=ldyH6F58hjVNhnMeZOfXhTo4aBYq11lEHFs+602BQUdrjf3OxaHRpFCr3mJwm120e22u8mM0r99KRz3T4Zxx4yALrToHw7sbXOdQfyR+AVEPXCUx84dzb/XwDOnj4gnJOkBOBjax/baNiaaKv7NoURMDXsSWTjKRVJ0E3cLHAo0= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R681e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037033178;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=34;SR=0;TI=SMTPD_---0X6gnBaq_1783493952; Received: from 30.246.161.237(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0X6gnBaq_1783493952 cluster:ay36) by smtp.aliyun-inc.com; Wed, 08 Jul 2026 14:59:14 +0800 Message-ID: <9228c07a-8879-41de-ba87-b9f879648ba8@linux.alibaba.com> Date: Wed, 8 Jul 2026 14:59:11 +0800 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 RESEND 4/7] riscv: stacktrace: introduce stack-bound tracking helpers To: Wang Han , 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, 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 References: <20260629072713.3273743-1-wanghan@linux.alibaba.com> <20260629072713.3273743-5-wanghan@linux.alibaba.com> From: Shuai Xue In-Reply-To: <20260629072713.3273743-5-wanghan@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/29/26 3:27 PM, Wang Han wrote: > A reliable unwinder needs to validate that every frame record it reads > is fully contained in a known kernel stack, and it needs to refuse to > walk back into a stack it has already left. Add the building blocks > for that: > > * struct stack_info / struct unwind_state in a new > asm/stacktrace/common.h, modelled on the arm64 reference > implementation. > * stackinfo_get_irq() / stackinfo_get_task() / stackinfo_get_overflow() > plus the corresponding on_*_stack() predicates in asm/stacktrace.h, > so callers can ask "is this object on stack X?" by stack kind > rather than open-coded address arithmetic. > * unwind_init_common(), unwind_find_stack() and > unwind_consume_stack() helpers that enforce the > forward-progress-only invariant required for reliability. > > No existing user is wired up to these helpers in this commit; the > unwinder switch comes in a follow-up. The header changes leave > on_thread_stack() with the same semantics as before, just expressed in > terms of the new helpers. > > Reviewed-by: Shuai Xue > Signed-off-by: Wang Han > --- > arch/riscv/include/asm/stacktrace.h | 65 ++++++++- > arch/riscv/include/asm/stacktrace/common.h | 159 +++++++++++++++++++++ > 2 files changed, 222 insertions(+), 2 deletions(-) > create mode 100644 arch/riscv/include/asm/stacktrace/common.h > > diff --git a/arch/riscv/include/asm/stacktrace.h b/arch/riscv/include/asm/stacktrace.h > index b1495a7e06ce..bc87c4940379 100644 > --- a/arch/riscv/include/asm/stacktrace.h > +++ b/arch/riscv/include/asm/stacktrace.h > @@ -3,8 +3,13 @@ > #ifndef _ASM_RISCV_STACKTRACE_H > #define _ASM_RISCV_STACKTRACE_H > > +#include > #include > +#include > + > +#include > #include > +#include > > struct stackframe { > unsigned long fp; > @@ -16,14 +21,70 @@ extern void notrace walk_stackframe(struct task_struct *task, struct pt_regs *re > extern void dump_backtrace(struct pt_regs *regs, struct task_struct *task, > const char *loglvl); > > -static inline bool on_thread_stack(void) > +/* > + * IRQ stack accessors > + */ > +static inline struct stack_info stackinfo_get_irq(void) > +{ > + unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr); From https://sashiko.dev/#/patchset/20260629072713.3273743-1-wanghan%40linux.alibaba.com Will this cause a link error when CONFIG_IRQ_STACKS is disabled? Looking at arch/riscv/kernel/irq.c, irq_stack_ptr is defined inside an #ifdef CONFIG_IRQ_STACKS block. Since stackinfo_get_irq() unconditionally references it here, it seems this might result in an undefined reference to irq_stack_ptr during linking. Should this accessor be conditionally compiled, or should it provide a fallback when CONFIG_IRQ_STACKS is not set? Thanks. Shuai