From: Pasha Tatashin <pasha.tatashin@soleen.com>
To: David Hildenbrand <david@redhat.com>
Cc: Ruihan Li <lrh2000@pku.edu.cn>,
linux-mm@kvack.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>,
Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
syzbot+fcf1a817ceb50935ce99@syzkaller.appspotmail.com,
stable@vger.kernel.org
Subject: Re: [PATCH v2 4/4] mm: page_table_check: Ensure user pages are not slab pages
Date: Tue, 16 May 2023 10:14:26 -0400 [thread overview]
Message-ID: <CA+CK2bAcnEm+2mUM0EbkeDZzRSS8qUWzi0nQhnHpb9+=b1Sf-w@mail.gmail.com> (raw)
In-Reply-To: <c60d3aa9-f8cd-6c78-3004-8017d7c95443@redhat.com>
> >> Acked-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> >>
> >> I would also update order in mm/memory.c
> >> static int validate_page_before_insert(struct page *page)
> >> {
> >> if (PageAnon(page) || PageSlab(page) || page_has_type(page))
> >>
> >> It is not strictly a bug there, as it works by accident, but
> >> PageSlab() should go before PageAnon(), because without checking if
> >> this is PageSlab() we should not be testing for PageAnon().
> >
> > Right. Perhaps it would be better to send another patch for this
> > separately.
Yes, as a separate from this series patch would work.
>
> Probably not really worth it IMHO. With PageSlab() we might have
> PageAnon() false-positives. Either will take the same path here ...
That is correct, it works by accident, but it is not a good idea to
keep a broken logic at least because it may be copied into other
places.
prev parent reply other threads:[~2023-05-16 14:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230515130958.32471-1-lrh2000@pku.edu.cn>
2023-05-15 13:09 ` [PATCH v2 1/4] usb: usbfs: Enforce page requirements for mmap Ruihan Li
2023-05-15 14:07 ` Alan Stern
2023-05-17 6:22 ` Christoph Hellwig
2023-05-15 13:09 ` [PATCH v2 2/4] usb: usbfs: Use consistent mmap functions Ruihan Li
2023-05-15 16:07 ` David Laight
2023-05-16 11:42 ` Ruihan Li
2023-05-15 13:09 ` [PATCH v2 3/4] mm: page_table_check: Make it dependent on EXCLUSIVE_SYSTEM_RAM Ruihan Li
2023-05-15 16:36 ` Pasha Tatashin
2023-05-16 12:55 ` David Hildenbrand
2023-05-15 13:09 ` [PATCH v2 4/4] mm: page_table_check: Ensure user pages are not slab pages Ruihan Li
2023-05-15 16:28 ` Pasha Tatashin
2023-05-16 11:51 ` Ruihan Li
2023-05-16 12:54 ` David Hildenbrand
2023-05-16 14:14 ` Pasha Tatashin [this message]
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