From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-131.freemail.mail.aliyun.com (out30-131.freemail.mail.aliyun.com [115.124.30.131]) (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 3698B3382F9; Wed, 3 Jun 2026 01:23:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780449798; cv=none; b=fnTE+6rXEWml7Bpmi+gVMjr1W+cm9y00DWJgp+PjydaQ+GUO92uE+2XFWqd0XIaVZaRHBXdpMOWkkSxAmIvCe130R2mkg/ie8BpYJ/qpfFRvFxgZm1ZdxpAUhTjNKAnjYezy2tK58jxXun6niTuOoZfsso8Hgra9DdVyYyd+ND4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780449798; c=relaxed/simple; bh=OUNnNBmYkrpRZR+iYgT2ZVhB2ELR6BFLJRgUu4+IxB8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MNdJSfpuujmKLtKEBR+qHOIG6t1Mf0AargJKNxerJLp4RmEpF2ig+lSLReDgQNSE7j4fEFSm1jXKOcg1CKeUYawHeCE/UlpQhgGw7Ae27xeiHgBSuaBfozRMu64cX9j6NH0tIfHf65gYyxIH0nvG+X2WY0kwZjVJ40pj3ivmhsM= 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=v0T79xHV; arc=none smtp.client-ip=115.124.30.131 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="v0T79xHV" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1780449793; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=aOvj40vd9kLAuQk7SPrErsDX1z7W+8ls3a4xdTv8HMg=; b=v0T79xHV3oyjexi2kUcB99zuD5zwCChUQcTVtyIWMr3NH9jrcttg/i8bENMBpmTU4ojqs99qJ/DiYt0y4XpxpAlOlFzc2eksLaM+X+El8GqP1IacuXySYZAUxwZT3NYi9uHv04Tye7ITyKr1UuDvozuqDldk3ota9UN4GRvw/S0= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R361e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037009110;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=34;SR=0;TI=SMTPD_---0X45kknw_1780449789; Received: from 30.246.177.175(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0X45kknw_1780449789 cluster:ay36) by smtp.aliyun-inc.com; Wed, 03 Jun 2026 09:23:11 +0800 Message-ID: <461a727f-e2cd-4192-9e19-16172500053c@linux.alibaba.com> Date: Wed, 3 Jun 2026 09:23:08 +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 v2 5/8] riscv: stacktrace: introduce stack-bound tracking helpers To: Wang Han , Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Steven Rostedt , Alexandre Ghiti , Masami Hiramatsu , Mark Rutland , Catalin Marinas , Chen Pei , Andy Chiu , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Deepak Gupta , Puranjay Mohan , Conor Dooley , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Shuah Khan , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , oliver.yang@linux.alibaba.com, zhuo.song@linux.alibaba.com, jkchen@linux.alibaba.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, live-patching@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-perf-users@vger.kernel.org References: <20260527123530.2593918-1-wanghan@linux.alibaba.com> <20260528082310.1994388-6-wanghan@linux.alibaba.com> From: Shuai Xue In-Reply-To: <20260528082310.1994388-6-wanghan@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/28/26 4:23 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. > > 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); > + unsigned long high = low + IRQ_STACK_SIZE; > + > + return (struct stack_info) { > + .low = low, > + .high = high, > + }; > +} > + > +static inline bool on_irq_stack(unsigned long sp, unsigned long size) > +{ > + struct stack_info info = stackinfo_get_irq(); > + > + return stackinfo_on_stack(&info, sp, size); > +} > + > +/* > + * Task stack accessors > + */ > +static inline struct stack_info stackinfo_get_task(const struct task_struct *tsk) > { > - return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1)); > + unsigned long low = (unsigned long)task_stack_page(tsk); > + unsigned long high = low + THREAD_SIZE; > + > + return (struct stack_info) { > + .low = low, > + .high = high, > + }; > +} > + > +static inline bool on_task_stack(const struct task_struct *tsk, > + unsigned long sp, unsigned long size) > +{ > + struct stack_info info = stackinfo_get_task(tsk); > + > + return stackinfo_on_stack(&info, sp, size); > } > > +/* > + * Cast is necessary since current->stack is an opaque ptr. > + */ > +#define on_thread_stack() (on_task_stack(current, current_stack_pointer, 1)) > > +/* > + * Overflow stack accessors > + */ > #ifdef CONFIG_VMAP_STACK > DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack); > + > +static inline struct stack_info stackinfo_get_overflow(void) > +{ > + unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack); > + unsigned long high = low + OVERFLOW_STACK_SIZE; > + > + return (struct stack_info) { > + .low = low, > + .high = high, > + }; > +} > #endif /* CONFIG_VMAP_STACK */ > > #endif /* _ASM_RISCV_STACKTRACE_H */ > diff --git a/arch/riscv/include/asm/stacktrace/common.h b/arch/riscv/include/asm/stacktrace/common.h > new file mode 100644 > index 000000000000..87d6d40672f3 > --- /dev/null > +++ b/arch/riscv/include/asm/stacktrace/common.h > @@ -0,0 +1,159 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * RISC-V common stack unwinder types and helpers. > + * > + * See: arch/arm64/include/asm/stacktrace/common.h for the reference > + * implementation. > + * > + * Copyright (C) 2024 Nit: The new common.h carries "Copyright (C) 2024", but this is a 2026 submission. Reviewed-by: Shuai Xue Thanks. Shuai