From: Oliver Upton <oliver.upton@linux.dev>
To: Gavin Shan <gshan@redhat.com>, Marc Zyngier <maz@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Shaoqin Huang <shahuang@redhat.com>,
Ricardo Koller <ricarkol@google.com>,
Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>,
Arnd Bergmann <arnd@arndb.de>,
kvmarm@lists.linux.dev, Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, Zenghui Yu <yuzenghui@huawei.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
James Morse <james.morse@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: kvm: avoid overflow in integer division
Date: Thu, 18 May 2023 17:45:47 +0000 [thread overview]
Message-ID: <168443190240.3857986.13123115778800174028.b4-ty@linux.dev> (raw)
In-Reply-To: <20230517202352.793673-1-arnd@kernel.org>
On Wed, 17 May 2023 22:23:39 +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The newly added kvm_mmu_split_nr_page_tables() function uses DIV_ROUND_DOWN_ULL()
> to divide 64-bit addresses, but this requires a 32-bit divisior, and PUD_SIZE
> may exceed that when 64KB pages are used:
>
> arch/arm64/kvm/mmu.c: In function 'kvm_mmu_split_nr_page_tables':
> include/linux/math.h:42:64: error: conversion from 'long unsigned int' to 'u32' {aka 'unsigned int'} changes value from '68719476736' to '0' [-Werror=overflow]
> 42 | DIV_ROUND_DOWN_ULL((unsigned long long)(ll) + (d) - 1, (d))
> | ^~~
> include/linux/math.h:39:47: note: in definition of macro 'DIV_ROUND_DOWN_ULL'
> 39 | #define DIV_ROUND_DOWN_ULL(ll, d) div_u64(ll, d)
> | ^
> arch/arm64/kvm/mmu.c:95:22: note: in expansion of macro 'DIV_ROUND_UP_ULL'
> 95 | n += DIV_ROUND_UP_ULL(range, PUD_SIZE);
> | ^~~~~~~~~~~~~~~~
>
> [...]
Applied to kvmarm/next, thanks!
[1/1] arm64: kvm: avoid overflow in integer division
https://git.kernel.org/kvmarm/kvmarm/c/14c3555f055d
--
Best,
Oliver
prev parent reply other threads:[~2023-05-18 17:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-17 20:23 Arnd Bergmann
2023-05-18 7:30 ` Marc Zyngier
2023-05-18 12:14 ` Arnd Bergmann
2023-05-18 17:45 ` Oliver Upton [this message]
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