From patchwork Fri Apr 1 00:58:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Gustavo A. R. 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R. Silva" To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH][next] x86/mm/pgtable: Fix Wstringop-overflow warnings Message-ID: <20220401005834.GA182932@embeddedor> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org 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 --- 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);