From: David Hildenbrand <david@redhat.com>
To: Matthew Wilcox <willy@infradead.org>,
Sean Christopherson <seanjc@google.com>,
Andi Kleen <ak@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
Dave Hansen <dave.hansen@intel.com>
Cc: linux-mm@kvack.org, x86@kernel.org
Subject: Re: [willy@infradead.org: Re: [syzbot] [mm?] BUG: Bad page map (7)]
Date: Mon, 11 Sep 2023 19:50:03 +0200 [thread overview]
Message-ID: <2d760884-051a-372c-a33d-a4bfe2f25675@redhat.com> (raw)
In-Reply-To: <ZP8q05EiU3jCs8al@casper.infradead.org>
> #ifndef set_ptes
> /**
> * set_ptes - Map consecutive pages to a contiguous range of addresses.
> @@ -231,7 +235,10 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
> if (--nr == 0)
> break;
> ptep++;
> - pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
> + if (__pte_needs_invert(pte_val(pte)))
> + pte = __pte(pte_val(pte) - (1UL << PFN_PTE_SHIFT));
> + else
> + pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
> }
Maybe we want some pte_advance() [or similar, you get the spirit] instead?
Leaking this inverted-pte logic into common code really does look nasty.
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2023-09-11 17:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-11 14:57 Matthew Wilcox
2023-09-11 17:50 ` David Hildenbrand [this message]
2023-09-13 21:28 ` Thomas Gleixner
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