From: Thomas Gleixner <tglx@linutronix.de>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: 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>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Baoquan He <bhe@redhat.com>, Ard Biesheuvel <ardb@kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
Sean Christopherson <seanjc@google.com>,
linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
Kai Huang <kai.huang@intel.com>
Subject: Re: [PATCHv2 1/4] x86/mm/ident_map: Fix virtual address wrap to zero
Date: Thu, 15 Aug 2024 12:57:49 +0200 [thread overview]
Message-ID: <87wmkim4sy.ffs@tglx> (raw)
In-Reply-To: <5iijyqzxd3ccranzvmfgvf3mvkesfbjsuggtuppa5wf6z444dd@ft5h2m6u2ggw>
On Thu, Aug 15 2024 at 12:15, Kirill A. Shutemov wrote:
> On Wed, Aug 14, 2024 at 09:25:35PM +0200, Thomas Gleixner wrote:
>> On Wed, Aug 14 2024 at 15:46, Kirill A. Shutemov wrote:
>> > Calculation of 'next' virtual address doesn't protect against wrapping
>> > to zero. It can result in page table corruption and hang. The
>> > problematic case is possible if user sets high x86_mapping_info::offset.
>>
>> So this should have a Fixes tag, right?
>
> Well, I guess we can add
>
> Fixes: e4630fdd4763 ("x86/power/64: Always create temporary identity mapping correctly")
>
> but the bug is not triggirable with current upstream code.
>
> It only wraps to zero if you touch top PGD entry. There's no such users in
> upstream. Only hibernate_64.c uses x86_mapping_info::offset and it works
> on direct mapping range which is not top PGD entry.
Fair enough, but please mention that in the change log.
next prev parent reply other threads:[~2024-08-15 10:57 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-14 12:46 [PATCHv2 0/4] x86: Reduce code duplication on page table initialization Kirill A. Shutemov
2024-08-14 12:46 ` [PATCHv2 1/4] x86/mm/ident_map: Fix virtual address wrap to zero Kirill A. Shutemov
2024-08-14 14:22 ` Tom Lendacky
2024-08-14 19:25 ` Thomas Gleixner
2024-08-15 9:15 ` Kirill A. Shutemov
2024-08-15 10:57 ` Thomas Gleixner [this message]
2024-08-14 12:46 ` [PATCHv2 2/4] x86/acpi: Replace manual page table initialization with kernel_ident_mapping_init() Kirill A. Shutemov
2024-08-14 15:55 ` Tom Lendacky
2024-08-14 12:46 ` [PATCHv2 3/4] x86/64/kexec: Map original relocate_kernel() in init_transition_pgtable() Kirill A. Shutemov
2024-08-15 6:15 ` Baoquan He
2024-08-15 9:18 ` Kirill A. Shutemov
2024-08-14 12:46 ` [PATCHv2 4/4] x86/64/kexec: Rewrite init_transition_pgtable() with kernel_ident_mapping_init() Kirill A. Shutemov
2024-08-14 16:02 ` Tom Lendacky
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