linux-kernel - Re: [PATCH v10 03/14] unwind_user: Add compat mode frame pointer support

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: <20250618134641.GJ1613376@noisy.programming.kicks-ass.net>
Date: Wed, 18 Jun 2025 15:46:41 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
	bpf@...r.kernel.org, x86@...nel.org,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Ingo Molnar <mingo@...nel.org>, Jiri Olsa <jolsa@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrii Nakryiko <andrii@...nel.org>,
	Indu Bhagat <indu.bhagat@...cle.com>,
	"Jose E. Marchesi" <jemarch@....org>,
	Beau Belgrave <beaub@...ux.microsoft.com>,
	Jens Remus <jremus@...ux.ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v10 03/14] unwind_user: Add compat mode frame pointer
 support

On Tue, Jun 10, 2025 at 08:54:24PM -0400, Steven Rostedt wrote:
> diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
> index 4fc550356b33..29e1f497a26e 100644
> --- a/kernel/unwind/user.c
> +++ b/kernel/unwind/user.c
> @@ -12,12 +12,32 @@ static struct unwind_user_frame fp_frame = {
>  	ARCH_INIT_USER_FP_FRAME
>  };
>  
> +static struct unwind_user_frame compat_fp_frame = {
> +	ARCH_INIT_USER_COMPAT_FP_FRAME
> +};
> +
>  static inline bool fp_state(struct unwind_user_state *state)
>  {
>  	return IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP) &&
>  	       state->type == UNWIND_USER_TYPE_FP;
>  }
>  
> +static inline bool compat_state(struct unwind_user_state *state)

Consistency would mandate this thing be called: compat_fp_state().

> +{
> +	return IS_ENABLED(CONFIG_HAVE_UNWIND_USER_COMPAT_FP) &&
> +	       state->type == UNWIND_USER_TYPE_COMPAT_FP;
> +}
> +
> +#define UNWIND_GET_USER_LONG(to, from, state)				\

Do we have to shout this?

> +({									\
> +	int __ret;							\
> +	if (compat_state(state))					\
> +		__ret = get_user(to, (u32 __user *)(from));		\
> +	else								\
> +		__ret = get_user(to, (unsigned long __user *)(from));	\
> +	__ret;								\
> +})
> +
>  int unwind_user_next(struct unwind_user_state *state)
>  {
>  	struct unwind_user_frame *frame;