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From: Thomas Gleixner <tglx@kernel.org>
To: David Stevens <stevensd@google.com>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Will Deacon <willdeacon@google.com>,
	Quentin Perret <qperret@google.com>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>, Xin Li <xin@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@kernel.org>,
	Lorenzo Stoakes <ljs@kernel.org>,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>,
	Vlastimil Babka <vbabka@kernel.org>,
	Mike Rapoport <rppt@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Michal Hocko <mhocko@suse.com>,
	Uladzislau Rezki <urezki@gmail.com>, Kees Cook <kees@kernel.org>
Cc: David Stevens <stevensd@google.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 10/13] fork: Store task pointer in unpopulated stack ptes
Date: Sat, 27 Jun 2026 00:46:35 +0200	[thread overview]
Message-ID: <87wlvkhqd0.ffs@fw13> (raw)
In-Reply-To: <20260424191456.2679717-11-stevensd@google.com>

On Fri, Apr 24 2026 at 12:14, David Stevens wrote:
> Store the task pointer in the ptes of the unpopulated pages of dynamic
> stacks, to allow the vm_struct pointer to be retrieved without relying
> on any locks or current.

You fail to explain why you can't use current. Changelogs have to
describe the WHY and not the WHAT.

>  
> -bool is_vmalloc_addr(const void *x)
> +noinstr bool is_vmalloc_addr(const void *x)
>  {
>  	unsigned long addr = (unsigned long)kasan_reset_tag(x);

noinstr is not enough here unless this depends on !KASAN because
kasan_reset_tag() is a 'static inline' which CLANG happily puts out of
line into the instrumentable section...



  reply	other threads:[~2026-06-26 22:46 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-24 19:14 [PATCH v2 00/13] Dynamic Kernel Stacks David Stevens
2026-04-24 19:14 ` [PATCH v2 01/13] fork: Remove assumption that vm_area->nr_pages equals to THREAD_SIZE David Stevens
2026-04-24 19:14 ` [PATCH v2 02/13] fork: Don't assume fully populated stack during reuse David Stevens
2026-04-24 19:14 ` [PATCH v2 03/13] fork: Move vm_stack to the beginning of the stack David Stevens
2026-04-24 19:14 ` [PATCH v2 04/13] fork: separate vmap stack allocation and free calls David Stevens
2026-04-24 19:14 ` [PATCH v2 05/13] mm/vmalloc: Add a get_vm_area_node() and vmap_pages_range() public functions David Stevens
2026-04-24 19:14 ` [PATCH v2 06/13] fork: Move vmap stack freeing to work queue David Stevens
2026-04-24 19:14 ` [PATCH v2 07/13] fork: Dynamic Kernel Stacks David Stevens
2026-04-24 19:14 ` [PATCH v2 08/13] task_stack.h: Add stack_not_used() support for dynamic stack David Stevens
2026-04-24 19:14 ` [PATCH v2 09/13] fork: Dynamic Kernel Stack accounting David Stevens
2026-04-24 19:14 ` [PATCH v2 10/13] fork: Store task pointer in unpopulated stack ptes David Stevens
2026-06-26 22:46   ` Thomas Gleixner [this message]
2026-04-24 19:14 ` [PATCH v2 11/13] x86/entry/fred: encode frame pointer on entry David Stevens
2026-04-24 19:14 ` [PATCH v2 12/13] x86: Add support for dynamic kernel stacks via FRED David Stevens
2026-06-26 22:39   ` Thomas Gleixner
2026-06-27  4:05     ` David Stevens
2026-04-24 19:14 ` [PATCH v2 13/13] x86: Add support for dynamic kernel stacks via IST David Stevens
2026-04-24 19:41 ` [PATCH v2 00/13] Dynamic Kernel Stacks Dave Hansen
2026-04-24 21:35   ` Pasha Tatashin
2026-04-24 22:21     ` Dave Hansen
2026-04-24 22:49       ` David Stevens
2026-04-24 22:26     ` David Laight
2026-04-24 23:06       ` Pasha Tatashin
2026-06-19  0:29       ` Dave Hansen
2026-06-19 19:56         ` Zach O'Keefe
2026-06-20  5:25         ` David Stevens
2026-06-20 23:22           ` Dave Hansen
2026-04-25  9:19   ` H. Peter Anvin
2026-04-27 16:17     ` Dave Hansen
2026-06-18 14:50       ` Zach O'Keefe
2026-06-18 18:53         ` Dave Hansen
2026-06-18 22:28           ` H. Peter Anvin
2026-06-19  0:40             ` David Stevens
2026-06-19  0:44               ` H. Peter Anvin
2026-06-19 12:45           ` Thomas Gleixner
2026-06-19 19:20             ` Zach O'Keefe
2026-06-19 21:59               ` Thomas Gleixner
2026-06-20  5:02                 ` David Stevens
2026-06-20 21:59                   ` Thomas Gleixner
2026-06-20 19:33                 ` Zach O'Keefe
2026-06-20 19:44                   ` H. Peter Anvin
2026-06-20 20:01                     ` Zach O'Keefe
2026-06-20 23:34                   ` Thomas Gleixner
2026-06-22 23:00                     ` Zach O'Keefe
2026-06-23  7:50                       ` David Hildenbrand (Arm)
2026-06-23  9:10                         ` David Laight
2026-06-23  9:19                           ` David Hildenbrand (Arm)
2026-06-23 21:58                       ` Thomas Gleixner
2026-06-25 11:56         ` Andrew Cooper
2026-06-25 21:38           ` H. Peter Anvin
2026-06-26  8:16         ` David Laight
2026-04-27 16:31     ` Pasha Tatashin

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