* [PATCH] efi/x86: Free efi_pgd with free_pages()
@ 2020-11-10 16:39 Arvind Sankar
2020-11-10 21:43 ` Ard Biesheuvel
2020-11-17 17:47 ` [tip: efi/urgent] " tip-bot2 for Arvind Sankar
0 siblings, 2 replies; 3+ messages in thread
From: Arvind Sankar @ 2020-11-10 16:39 UTC (permalink / raw)
To: Ard Biesheuvel, linux-efi; +Cc: linux-kernel
Commit
d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
changed the PGD allocation to allocate PGD_ALLOCATION_ORDER pages, so in
the error path it should be freed using free_pages() rather than
free_page().
Commit
06ace26f4e6f ("x86/efi: Free efi_pgd with free_pages()")
fixed one instance of this, but missed another.
Move the freeing out-of-line to avoid code duplication and fix this bug.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Fixes: d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
---
arch/x86/platform/efi/efi_64.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 8f5759df7776..e1e8d4e3a213 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -78,28 +78,30 @@ int __init efi_alloc_page_tables(void)
gfp_mask = GFP_KERNEL | __GFP_ZERO;
efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
if (!efi_pgd)
- return -ENOMEM;
+ goto fail;
pgd = efi_pgd + pgd_index(EFI_VA_END);
p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
- if (!p4d) {
- free_page((unsigned long)efi_pgd);
- return -ENOMEM;
- }
+ if (!p4d)
+ goto free_pgd;
pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
- if (!pud) {
- if (pgtable_l5_enabled())
- free_page((unsigned long) pgd_page_vaddr(*pgd));
- free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
- return -ENOMEM;
- }
+ if (!pud)
+ goto free_p4d;
efi_mm.pgd = efi_pgd;
mm_init_cpumask(&efi_mm);
init_new_context(NULL, &efi_mm);
return 0;
+
+free_p4d:
+ if (pgtable_l5_enabled())
+ free_page((unsigned long)pgd_page_vaddr(*pgd));
+free_pgd:
+ free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
+fail:
+ return -ENOMEM;
}
/*
--
2.26.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] efi/x86: Free efi_pgd with free_pages()
2020-11-10 16:39 [PATCH] efi/x86: Free efi_pgd with free_pages() Arvind Sankar
@ 2020-11-10 21:43 ` Ard Biesheuvel
2020-11-17 17:47 ` [tip: efi/urgent] " tip-bot2 for Arvind Sankar
1 sibling, 0 replies; 3+ messages in thread
From: Ard Biesheuvel @ 2020-11-10 21:43 UTC (permalink / raw)
To: Arvind Sankar; +Cc: linux-efi, Linux Kernel Mailing List
On Tue, 10 Nov 2020 at 17:39, Arvind Sankar <nivedita@alum.mit.edu> wrote:
>
> Commit
> d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
> changed the PGD allocation to allocate PGD_ALLOCATION_ORDER pages, so in
> the error path it should be freed using free_pages() rather than
> free_page().
>
> Commit
> 06ace26f4e6f ("x86/efi: Free efi_pgd with free_pages()")
> fixed one instance of this, but missed another.
>
> Move the freeing out-of-line to avoid code duplication and fix this bug.
>
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> Fixes: d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
Thanks Arvind. I'll queue this as a fix.
> ---
> arch/x86/platform/efi/efi_64.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 8f5759df7776..e1e8d4e3a213 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -78,28 +78,30 @@ int __init efi_alloc_page_tables(void)
> gfp_mask = GFP_KERNEL | __GFP_ZERO;
> efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
> if (!efi_pgd)
> - return -ENOMEM;
> + goto fail;
>
> pgd = efi_pgd + pgd_index(EFI_VA_END);
> p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
> - if (!p4d) {
> - free_page((unsigned long)efi_pgd);
> - return -ENOMEM;
> - }
> + if (!p4d)
> + goto free_pgd;
>
> pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
> - if (!pud) {
> - if (pgtable_l5_enabled())
> - free_page((unsigned long) pgd_page_vaddr(*pgd));
> - free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
> - return -ENOMEM;
> - }
> + if (!pud)
> + goto free_p4d;
>
> efi_mm.pgd = efi_pgd;
> mm_init_cpumask(&efi_mm);
> init_new_context(NULL, &efi_mm);
>
> return 0;
> +
> +free_p4d:
> + if (pgtable_l5_enabled())
> + free_page((unsigned long)pgd_page_vaddr(*pgd));
> +free_pgd:
> + free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
> +fail:
> + return -ENOMEM;
> }
>
> /*
> --
> 2.26.2
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* [tip: efi/urgent] efi/x86: Free efi_pgd with free_pages()
2020-11-10 16:39 [PATCH] efi/x86: Free efi_pgd with free_pages() Arvind Sankar
2020-11-10 21:43 ` Ard Biesheuvel
@ 2020-11-17 17:47 ` tip-bot2 for Arvind Sankar
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot2 for Arvind Sankar @ 2020-11-17 17:47 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Arvind Sankar, Ard Biesheuvel, x86, linux-kernel
The following commit has been merged into the efi/urgent branch of tip:
Commit-ID: c2fe61d8be491ff8188edaf22e838f819999146b
Gitweb: https://git.kernel.org/tip/c2fe61d8be491ff8188edaf22e838f819999146b
Author: Arvind Sankar <nivedita@alum.mit.edu>
AuthorDate: Tue, 10 Nov 2020 11:39:19 -05:00
Committer: Ard Biesheuvel <ardb@kernel.org>
CommitterDate: Tue, 10 Nov 2020 19:18:11 +01:00
efi/x86: Free efi_pgd with free_pages()
Commit
d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
changed the PGD allocation to allocate PGD_ALLOCATION_ORDER pages, so in
the error path it should be freed using free_pages() rather than
free_page().
Commit
06ace26f4e6f ("x86/efi: Free efi_pgd with free_pages()")
fixed one instance of this, but missed another.
Move the freeing out-of-line to avoid code duplication and fix this bug.
Fixes: d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
Link: https://lore.kernel.org/r/20201110163919.1134431-1-nivedita@alum.mit.edu
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/platform/efi/efi_64.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 8f5759d..e1e8d4e 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -78,28 +78,30 @@ int __init efi_alloc_page_tables(void)
gfp_mask = GFP_KERNEL | __GFP_ZERO;
efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
if (!efi_pgd)
- return -ENOMEM;
+ goto fail;
pgd = efi_pgd + pgd_index(EFI_VA_END);
p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
- if (!p4d) {
- free_page((unsigned long)efi_pgd);
- return -ENOMEM;
- }
+ if (!p4d)
+ goto free_pgd;
pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
- if (!pud) {
- if (pgtable_l5_enabled())
- free_page((unsigned long) pgd_page_vaddr(*pgd));
- free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
- return -ENOMEM;
- }
+ if (!pud)
+ goto free_p4d;
efi_mm.pgd = efi_pgd;
mm_init_cpumask(&efi_mm);
init_new_context(NULL, &efi_mm);
return 0;
+
+free_p4d:
+ if (pgtable_l5_enabled())
+ free_page((unsigned long)pgd_page_vaddr(*pgd));
+free_pgd:
+ free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
+fail:
+ return -ENOMEM;
}
/*
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2020-11-10 16:39 [PATCH] efi/x86: Free efi_pgd with free_pages() Arvind Sankar
2020-11-10 21:43 ` Ard Biesheuvel
2020-11-17 17:47 ` [tip: efi/urgent] " tip-bot2 for Arvind Sankar
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