From: "Gustavo A. R. Silva" <gustavoars@kernel.org>
To: 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>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
linux-hardening@vger.kernel.org
Subject: [PATCH][next] x86/mm/pgtable: Fix Wstringop-overflow warnings
Date: Thu, 31 Mar 2022 19:58:34 -0500 [thread overview]
Message-ID: <20220401005834.GA182932@embeddedor> (raw)
Fix the following -Wstringop-overflow warnings when building with GCC-11:
.arch/x86/mm/pgtable.c: In function ‘pgd_alloc’:
arch/x86/mm/pgtable.c:437:13: warning: ‘preallocate_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
437 | if (preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:437:13: note: referencing argument 2 of type ‘pmd_t **’
arch/x86/mm/pgtable.c:225:12: note: in a call to function ‘preallocate_pmds.constprop’
225 | static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
| ^~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:440:13: warning: ‘preallocate_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
440 | if (preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:440:13: note: referencing argument 2 of type ‘pmd_t **’
arch/x86/mm/pgtable.c:225:12: note: in a call to function ‘preallocate_pmds.constprop’
225 | static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
| ^~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:462:9: warning: ‘free_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
462 | free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:462:9: note: referencing argument 2 of type ‘pmd_t **’
arch/x86/mm/pgtable.c:213:13: note: in a call to function ‘free_pmds.constprop’
213 | static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
| ^~~~~~~~~
arch/x86/mm/pgtable.c:455:9: warning: ‘pgd_prepopulate_user_pmd’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
455 | pgd_prepopulate_user_pmd(mm, pgd, u_pmds);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:455:9: note: referencing argument 3 of type ‘pmd_t **’
arch/x86/mm/pgtable.c:320:13: note: in a call to function ‘pgd_prepopulate_user_pmd’
320 | static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
| ^~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:464:9: warning: ‘free_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
464 | free_pmds(mm, pmds, PREALLOCATED_PMDS);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/mm/pgtable.c:464:9: note: referencing argument 2 of type ‘pmd_t **’
arch/x86/mm/pgtable.c:213:13: note: in a call to function ‘free_pmds.constprop’
213 | static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
| ^~~~~~~~~
by using pointer notation instead of array notation as a workaround for
the above GCC warnings.
This helps with the ongoing efforts to globally enable
-Wstringop-overflow.
Link: https://github.com/KSPP/linux/issues/181
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
arch/x86/mm/pgtable.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 3481b35cb4ec..aecaebf3c3d0 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -210,7 +210,7 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
#define MAX_PREALLOCATED_USER_PMDS 0
#endif /* CONFIG_X86_PAE */
-static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
+static void free_pmds(struct mm_struct *mm, pmd_t **pmds, int count)
{
int i;
@@ -222,7 +222,7 @@ static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
}
}
-static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
+static int preallocate_pmds(struct mm_struct *mm, pmd_t **pmds, int count)
{
int i;
bool failed = false;
@@ -318,7 +318,7 @@ static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
#ifdef CONFIG_PAGE_TABLE_ISOLATION
static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
- pgd_t *k_pgd, pmd_t *pmds[])
+ pgd_t *k_pgd, pmd_t **pmds)
{
pgd_t *s_pgd = kernel_to_user_pgdp(swapper_pg_dir);
pgd_t *u_pgd = kernel_to_user_pgdp(k_pgd);
--
2.27.0
next reply other threads:[~2022-04-01 0:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-01 0:58 Gustavo A. R. Silva [this message]
2022-04-01 13:12 ` [PATCH][next] x86/mm/pgtable: Fix Wstringop-overflow warnings Peter Zijlstra
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