linux-kernel - Re: [PATCH v4 11/39] unwind_user: Add user space unwinding API

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250124150211.4e252fc8@gandalf.local.home>
Date: Fri, 24 Jan 2025 15:02:11 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Josh Poimboeuf <jpoimboe@...nel.org>
Cc: x86@...nel.org, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar
 <mingo@...nel.org>, Arnaldo Carvalho de Melo <acme@...nel.org>,
 linux-kernel@...r.kernel.org, Indu Bhagat <indu.bhagat@...cle.com>, Mark
 Rutland <mark.rutland@....com>, Alexander Shishkin
 <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
 Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>, Adrian
 Hunter <adrian.hunter@...el.com>, linux-perf-users@...r.kernel.org, Mark
 Brown <broonie@...nel.org>, linux-toolchains@...r.kernel.org, Jordan Rome
 <jordalgo@...a.com>, Sam James <sam@...too.org>,
 linux-trace-kernel@...r.kernel.org, Andrii Nakryiko
 <andrii.nakryiko@...il.com>, Jens Remus <jremus@...ux.ibm.com>, Mathieu
 Desnoyers <mathieu.desnoyers@...icios.com>, Florian Weimer
 <fweimer@...hat.com>, Andy Lutomirski <luto@...nel.org>, Masami Hiramatsu
 <mhiramat@...nel.org>, Weinan Liu <wnliu@...gle.com>
Subject: Re: [PATCH v4 11/39] unwind_user: Add user space unwinding API

On Tue, 21 Jan 2025 18:31:03 -0800
Josh Poimboeuf <jpoimboe@...nel.org> wrote:

> +int unwind_user_next(struct unwind_user_state *state)
> +{
> +	struct unwind_user_frame _frame;
> +	struct unwind_user_frame *frame = &_frame;
> +	unsigned long cfa = 0, fp, ra = 0;
> +
> +	/* no implementation yet */
> +	-EINVAL;
> +}
> +
> +int unwind_user_start(struct unwind_user_state *state)
> +{
> +	struct pt_regs *regs = task_pt_regs(current);
> +
> +	memset(state, 0, sizeof(*state));
> +
> +	if (!current->mm || !user_mode(regs)) {
> +		state->done = true;
> +		return -EINVAL;
> +	}
> +
> +	state->type = UNWIND_USER_TYPE_NONE;
> +
> +	state->ip = instruction_pointer(regs);
> +	state->sp = user_stack_pointer(regs);
> +	state->fp = frame_pointer(regs);
> +
> +	return 0;
> +}
> +

I know this is just an introductory of the interface, but this should
really have kerneldoc attached to it, as I have no idea what these are
supposed to be doing. This patch is meaningless without it. The change log
is useless too.

-- Steve


> +int unwind_user(struct unwind_stacktrace *trace, unsigned int max_entries)
> +{
> +	struct unwind_user_state state;
> +
> +	trace->nr = 0;
> +
> +	if (!max_entries)
> +		return -EINVAL;
> +
> +	if (!current->mm)
> +		return 0;
> +
> +	for_each_user_frame(&state) {
> +		trace->entries[trace->nr++] = state.ip;
> +		if (trace->nr >= max_entries)
> +			break;
> +	}
> +
> +	return 0;
> +}