From: Kees Cook <keescook@chromium.org>
To: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2][next] x86/mm/pgtable: Fix -Wstringop-overflow warnings
Date: Wed, 11 May 2022 11:41:25 -0700 [thread overview]
Message-ID: <202205111140.21530A125@keescook> (raw)
In-Reply-To: <20220510141202.GA6878@embeddedor>
On Tue, May 10, 2022 at 09:12:02AM -0500, Gustavo A. R. Silva wrote:
> It doesn't seem to work... however, the following piece of code implies
> that pmds and u_pmds should be first preallocated through preallocate_pmds(),
> which cannot happen if (MAX_PREALLOCATED_PMDS != 0 && MAX_PREALLOCATED_USER_PMDS != 0)
This works, weirdly:
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 3481b35cb4ec..937a87b404c3 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -424,8 +424,8 @@ static inline void _pgd_free(pgd_t *pgd)
pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd;
- pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
- pmd_t *pmds[MAX_PREALLOCATED_PMDS];
+ pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS + 1];
+ pmd_t *pmds[MAX_PREALLOCATED_PMDS + 1];
pgd = _pgd_alloc();
--
Kees Cook
prev parent reply other threads:[~2022-05-11 18:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-09 19:45 [PATCH v2][next] x86/mm/pgtable: Fix -Wstringop-overflow warnings Gustavo A. R. Silva
2022-05-09 19:59 ` Kees Cook
2022-05-09 20:50 ` Gustavo A. R. Silva
2022-05-09 20:54 ` Kees Cook
2022-05-10 14:12 ` Gustavo A. R. Silva
2022-05-10 14:54 ` Gustavo A. R. Silva
2022-05-11 18:41 ` Kees Cook [this message]
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