From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, songmuchun@bytedance.com,
zhouchengming@bytedance.com, akpm@linux-foundation.org,
tglx@linutronix.de, kirill.shutemov@linux.intel.com,
jgg@nvidia.com, tj@kernel.org, dennis@kernel.org,
ming.lei@redhat.com
Subject: Re: [RFC PATCH 00/18] Try to free user PTE page table pages
Date: Wed, 18 May 2022 15:56:17 +0100 [thread overview]
Message-ID: <YoUJEZU9JcfMlhRO@casper.infradead.org> (raw)
In-Reply-To: <37055be1-05af-f7ef-c33e-27f90fa0f9ca@redhat.com>
On Wed, May 18, 2022 at 04:51:06PM +0200, David Hildenbrand wrote:
> yes, I talked about the involved challenges, especially, how malicious
> user space can trigger allocation of almost elusively page tables and
> essentially consume a lot of unmovable+unswappable memory and even store
> secrets in the page table structure.
There are a lot of ways for userspace to consume a large amount of
kernel memory. For example, one can open a file and set file locks on
alternate bytes. We generally handle this by accounting the memory to
the process and let the OOM killer, rlimits, memcg or other mechanism
take care of it. Just because page tables are (generally) reclaimable
doesn't mean we need to treat them specially.
next prev parent reply other threads:[~2022-05-18 14:56 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-29 13:35 Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 01/18] x86/mm/encrypt: add the missing pte_unmap() call Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 02/18] percpu_ref: make ref stable after percpu_ref_switch_to_atomic_sync() returns Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 03/18] percpu_ref: make percpu_ref_switch_lock per percpu_ref Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 04/18] mm: convert to use ptep_clear() in pte_clear_not_present_full() Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 05/18] mm: split the related definitions of pte_offset_map_lock() into pgtable.h Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 06/18] mm: introduce CONFIG_FREE_USER_PTE Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 07/18] mm: add pte_to_page() helper Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 08/18] mm: introduce percpu_ref for user PTE page table page Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 09/18] pte_ref: add pte_tryget() and {__,}pte_put() helper Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 10/18] mm: add pte_tryget_map{_lock}() helper Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 11/18] mm: convert to use pte_tryget_map_lock() Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 12/18] mm: convert to use pte_tryget_map() Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 13/18] mm: add try_to_free_user_pte() helper Qi Zheng
2022-04-30 13:35 ` Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 14/18] mm: use try_to_free_user_pte() in MADV_DONTNEED case Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 15/18] mm: use try_to_free_user_pte() in MADV_FREE case Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 16/18] pte_ref: add track_pte_{set, clear}() helper Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 17/18] x86/mm: add x86_64 support for pte_ref Qi Zheng
2022-04-29 13:35 ` [RFC PATCH 18/18] Documentation: add document " Qi Zheng
2022-04-30 13:19 ` Bagas Sanjaya
2022-04-30 13:32 ` Qi Zheng
2022-05-17 8:30 ` [RFC PATCH 00/18] Try to free user PTE page table pages Qi Zheng
2022-05-18 14:51 ` David Hildenbrand
2022-05-18 14:56 ` Matthew Wilcox [this message]
2022-05-19 4:03 ` Qi Zheng
2022-05-19 3:58 ` Qi Zheng
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