linux-kernel - Re: [tip: x86/mm] x86/mm/tlb: Update mm

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] [day] [month] [year] [list]

Message-ID: <20241119125432.GF2328@noisy.programming.kicks-ass.net>
Date: Tue, 19 Nov 2024 13:54:32 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: linux-kernel@...r.kernel.org
Cc: linux-tip-commits@...r.kernel.org, Rik van Riel <riel@...riel.com>,
	Ingo Molnar <mingo@...nel.org>, Dave Hansen <dave.hansen@...el.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Mel Gorman <mgorman@...e.de>, x86@...nel.org
Subject: Re: [tip: x86/mm] x86/mm/tlb: Update mm_cpumask lazily

On Tue, Nov 19, 2024 at 11:27:35AM -0000, tip-bot2 for Rik van Riel wrote:
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index d17518c..8b66a55 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -1825,11 +1825,18 @@ static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm)
>  	return temp_state;
>  }
>  
> +__ro_after_init struct mm_struct *poking_mm;
> +__ro_after_init unsigned long poking_addr;
> +
>  static inline void unuse_temporary_mm(temp_mm_state_t prev_state)
>  {
>  	lockdep_assert_irqs_disabled();
> +
>  	switch_mm_irqs_off(NULL, prev_state.mm, current);
>  
> +	/* Clear the cpumask, to indicate no TLB flushing is needed anywhere */
> +	cpumask_clear_cpu(raw_smp_processor_id(), mm_cpumask(poking_mm));

Oh bugger, this is really unfortunate.

Let me try and fix this.