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From: Peter Zijlstra <peterz@infradead.org>
To: "Thomas Weißschuh" <thomas.weissschuh@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Boqun Feng <boqun@kernel.org>, Waiman Long <longman@redhat.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Clark Williams <clrkwllms@kernel.org>,
	Kees Cook <kees@kernel.org>,
	linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev
Subject: Re: [PATCH v2 4/4] lib/vsprintf: Always check interrupt context restrictions
Date: Mon, 4 May 2026 15:00:44 +0200	[thread overview]
Message-ID: <20260504130044.GU3126523@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20260504-restricted-pointers-final-v2-4-4934933503e5@linutronix.de>

On Mon, May 04, 2026 at 12:47:20PM +0200, Thomas Weißschuh wrote:
> When kptr_restrict is set to '1' restricted pointers can not be used
> in IRQ context. As kptr_restrict can change at any time at runtime,
> this means that restricted pointers can not be used from IRQ context
> in general.
> 
> Add some assertions to detect misuse early, independently of the
> runtime configuration of the test system.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> ---
>  lib/vsprintf.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 021db95087fe..185bd9e61144 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -871,6 +871,10 @@ char *restricted_pointer(char *buf, char *end, const void *ptr,
>  
>  	guard(lock_map_acquire)(&vsprintf_restricted_pointer_map);
>  
> +	lockdep_assert(!in_hardirq());
> +	lockdep_assert(!in_serving_softirq());
> +	lockdep_assert(!in_nmi());
> +

did that want to be:

	lockdep_assert(in_task());

	?

  reply	other threads:[~2026-05-04 13:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-04 10:47 [PATCH v2 0/4] lib/vsprintf: Validate spinlock context during restricted pointer formatting Thomas Weißschuh
2026-05-04 10:47 ` [PATCH v2 1/4] locking/lockdep: Add a helper to validate the locking context without a lock Thomas Weißschuh
2026-05-04 10:47 ` [PATCH v2 2/4] locking/lockdep: Add a guard for lock_map_acquire() Thomas Weißschuh
2026-05-04 10:47 ` [PATCH v2 3/4] lib/vsprintf: Validate spinlock context during restricted pointer formatting Thomas Weißschuh
2026-05-04 10:47 ` [PATCH v2 4/4] lib/vsprintf: Always check interrupt context restrictions Thomas Weißschuh
2026-05-04 13:00   ` Peter Zijlstra [this message]
2026-05-04 13:02     ` Sebastian Andrzej Siewior
2026-05-04 13:20     ` Thomas Weißschuh

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