2021-10-21 07:11:00

by Mike Rapoport

[permalink] [raw]
Subject: [PATCH v2 2/2] memblock: exclude MEMBLOCK_NOMAP regions from kmemleak

From: Mike Rapoport <[email protected]>

Vladimir Zapolskiy reports:

commit a7259df76702 ("memblock: make memblock_find_in_range method private")
invokes a kernel panic while running kmemleak on OF platforms with nomaped
regions:

Unable to handle kernel paging request at virtual address fff000021e00000
[...]
scan_block+0x64/0x170
scan_gray_list+0xe8/0x17c
kmemleak_scan+0x270/0x514
kmemleak_write+0x34c/0x4ac

The memory allocated from memblock is registered with kmemleak, but if it
is marked MEMBLOCK_NOMAP it won't have linear map entries so an attempt to
scan such areas will fault.

Ideally, memblock_mark_nomap() would inform kmemleak to ignore
MEMBLOCK_NOMAP memory, but it can be called before kmemleak interfaces
operating on physical addresses can use __va() conversion.

Make sure that functions that mark allocated memory as MEMBLOCK_NOMAP take
care of informing kmemleak to ignore such memory.

Link: https://lore.kernel.org/all/[email protected]
Link: https://lore.kernel.org/all/[email protected]
Fixes: a7259df76702 ("memblock: make memblock_find_in_range method private")
Reported-by: Vladimir Zapolskiy <[email protected]>
Signed-off-by: Mike Rapoport <[email protected]>
---
drivers/acpi/tables.c | 3 +++
drivers/of/of_reserved_mem.c | 2 ++
mm/memblock.c | 3 +++
3 files changed, 8 insertions(+)

diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index f9383736fa0f..71419eb16e09 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -21,6 +21,7 @@
#include <linux/earlycpio.h>
#include <linux/initrd.h>
#include <linux/security.h>
+#include <linux/kmemleak.h>
#include "internal.h"

#ifdef CONFIG_ACPI_CUSTOM_DSDT
@@ -601,6 +602,8 @@ void __init acpi_table_upgrade(void)
*/
arch_reserve_mem_area(acpi_tables_addr, all_tables_size);

+ kmemleak_ignore_phys(acpi_tables_addr);
+
/*
* early_ioremap only can remap 256k one time. If we map all
* tables one time, we will hit the limit. Need to map chunks
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 59c1390cdf42..9da8835ba5a5 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -21,6 +21,7 @@
#include <linux/sort.h>
#include <linux/slab.h>
#include <linux/memblock.h>
+#include <linux/kmemleak.h>

#include "of_private.h"

@@ -46,6 +47,7 @@ static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
err = memblock_mark_nomap(base, size);
if (err)
memblock_free(base, size);
+ kmemleak_ignore_phys(base);
}

return err;
diff --git a/mm/memblock.c b/mm/memblock.c
index 184dcd2e5d99..dab804b09d62 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -932,6 +932,9 @@ int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
* covered by the memory map. The struct page representing NOMAP memory
* frames in the memory map will be PageReserved()
*
+ * Note: if the memory being marked %MEMBLOCK_NOMAP was allocated from
+ * memblock, the caller must inform kmemleak to ignore that memory
+ *
* Return: 0 on success, -errno on failure.
*/
int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
--
2.28.0


2021-10-21 08:08:38

by Vladimir Zapolskiy

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] memblock: exclude MEMBLOCK_NOMAP regions from kmemleak

Hi Mike,

On 10/21/21 10:09 AM, Mike Rapoport wrote:
> From: Mike Rapoport <[email protected]>
>
> Vladimir Zapolskiy reports:
>
> commit a7259df76702 ("memblock: make memblock_find_in_range method private")
> invokes a kernel panic while running kmemleak on OF platforms with nomaped
> regions:
>
> Unable to handle kernel paging request at virtual address fff000021e00000
> [...]
> scan_block+0x64/0x170
> scan_gray_list+0xe8/0x17c
> kmemleak_scan+0x270/0x514
> kmemleak_write+0x34c/0x4ac
>
> The memory allocated from memblock is registered with kmemleak, but if it
> is marked MEMBLOCK_NOMAP it won't have linear map entries so an attempt to
> scan such areas will fault.
>
> Ideally, memblock_mark_nomap() would inform kmemleak to ignore
> MEMBLOCK_NOMAP memory, but it can be called before kmemleak interfaces
> operating on physical addresses can use __va() conversion.
>
> Make sure that functions that mark allocated memory as MEMBLOCK_NOMAP take
> care of informing kmemleak to ignore such memory.
>
> Link: https://lore.kernel.org/all/[email protected]
> Link: https://lore.kernel.org/all/[email protected]
> Fixes: a7259df76702 ("memblock: make memblock_find_in_range method private")
> Reported-by: Vladimir Zapolskiy <[email protected]>
> Signed-off-by: Mike Rapoport <[email protected]>

this change variant also solves the reported problem, thank you.

Tested-by: Vladimir Zapolskiy <[email protected]>

--
Best wishes,
Vladimir

2021-10-21 08:33:31

by Catalin Marinas

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] memblock: exclude MEMBLOCK_NOMAP regions from kmemleak

On Thu, Oct 21, 2021 at 10:09:29AM +0300, Mike Rapoport wrote:
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index f9383736fa0f..71419eb16e09 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -21,6 +21,7 @@
> #include <linux/earlycpio.h>
> #include <linux/initrd.h>
> #include <linux/security.h>
> +#include <linux/kmemleak.h>
> #include "internal.h"
>
> #ifdef CONFIG_ACPI_CUSTOM_DSDT
> @@ -601,6 +602,8 @@ void __init acpi_table_upgrade(void)
> */
> arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
>
> + kmemleak_ignore_phys(acpi_tables_addr);
> +
> /*
> * early_ioremap only can remap 256k one time. If we map all
> * tables one time, we will hit the limit. Need to map chunks
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 59c1390cdf42..9da8835ba5a5 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -21,6 +21,7 @@
> #include <linux/sort.h>
> #include <linux/slab.h>
> #include <linux/memblock.h>
> +#include <linux/kmemleak.h>
>
> #include "of_private.h"
>
> @@ -46,6 +47,7 @@ static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
> err = memblock_mark_nomap(base, size);
> if (err)
> memblock_free(base, size);
> + kmemleak_ignore_phys(base);
> }
>
> return err;

More of a nitpick as there's no kmemleak scanning to race with during
early boot: I'd normally call kmemleak_ignore_phys() before marking it
nomap. Either way:

Reviewed-by: Catalin Marinas <[email protected]>

2021-10-22 12:24:15

by David Hildenbrand

[permalink] [raw]
Subject: Re: [PATCH v2 2/2] memblock: exclude MEMBLOCK_NOMAP regions from kmemleak

On 21.10.21 09:09, Mike Rapoport wrote:
> From: Mike Rapoport <[email protected]>
>
> Vladimir Zapolskiy reports:
>
> commit a7259df76702 ("memblock: make memblock_find_in_range method private")
> invokes a kernel panic while running kmemleak on OF platforms with nomaped
> regions:
>
> Unable to handle kernel paging request at virtual address fff000021e00000
> [...]
> scan_block+0x64/0x170
> scan_gray_list+0xe8/0x17c
> kmemleak_scan+0x270/0x514
> kmemleak_write+0x34c/0x4ac
>
> The memory allocated from memblock is registered with kmemleak, but if it
> is marked MEMBLOCK_NOMAP it won't have linear map entries so an attempt to
> scan such areas will fault.
>
> Ideally, memblock_mark_nomap() would inform kmemleak to ignore
> MEMBLOCK_NOMAP memory, but it can be called before kmemleak interfaces
> operating on physical addresses can use __va() conversion.
>
> Make sure that functions that mark allocated memory as MEMBLOCK_NOMAP take
> care of informing kmemleak to ignore such memory.
>
> Link: https://lore.kernel.org/all/[email protected]
> Link: https://lore.kernel.org/all/[email protected]
> Fixes: a7259df76702 ("memblock: make memblock_find_in_range method private")
> Reported-by: Vladimir Zapolskiy <[email protected]>
> Signed-off-by: Mike Rapoport <[email protected]>
> ---
> drivers/acpi/tables.c | 3 +++
> drivers/of/of_reserved_mem.c | 2 ++
> mm/memblock.c | 3 +++
> 3 files changed, 8 insertions(+)
>
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index f9383736fa0f..71419eb16e09 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -21,6 +21,7 @@
> #include <linux/earlycpio.h>
> #include <linux/initrd.h>
> #include <linux/security.h>
> +#include <linux/kmemleak.h>
> #include "internal.h"
>
> #ifdef CONFIG_ACPI_CUSTOM_DSDT
> @@ -601,6 +602,8 @@ void __init acpi_table_upgrade(void)
> */
> arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
>
> + kmemleak_ignore_phys(acpi_tables_addr);
> +
> /*
> * early_ioremap only can remap 256k one time. If we map all
> * tables one time, we will hit the limit. Need to map chunks
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 59c1390cdf42..9da8835ba5a5 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -21,6 +21,7 @@
> #include <linux/sort.h>
> #include <linux/slab.h>
> #include <linux/memblock.h>
> +#include <linux/kmemleak.h>
>
> #include "of_private.h"
>
> @@ -46,6 +47,7 @@ static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
> err = memblock_mark_nomap(base, size);
> if (err)
> memblock_free(base, size);
> + kmemleak_ignore_phys(base);
> }
>
> return err;
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 184dcd2e5d99..dab804b09d62 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -932,6 +932,9 @@ int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
> * covered by the memory map. The struct page representing NOMAP memory
> * frames in the memory map will be PageReserved()
> *
> + * Note: if the memory being marked %MEMBLOCK_NOMAP was allocated from
> + * memblock, the caller must inform kmemleak to ignore that memory
> + *
> * Return: 0 on success, -errno on failure.
> */
> int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size)
>

Reviewed-by: David Hildenbrand <[email protected]>

--
Thanks,

David / dhildenb