Commit 9099daed authored by Catalin Marinas's avatar Catalin Marinas Committed by Linus Torvalds
Browse files

mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping 

Some of the kmemleak_*() callbacks in memblock, bootmem, CMA convert a
physical address to a virtual one using __va().  However, such physical
addresses may sometimes be located in highmem and using __va() is
incorrect, leading to inconsistent object tracking in kmemleak.

The following functions have been added to the kmemleak API and they take
a physical address as the object pointer.  They only perform the
corresponding action if the address has a lowmem mapping:

kmemleak_alloc_phys
kmemleak_free_part_phys
kmemleak_not_leak_phys
kmemleak_ignore_phys

The affected calling places have been updated to use the new kmemleak
API.

Link: http://lkml.kernel.org/r/1471531432-16503-1-git-send-email-catalin.marinas@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reported-by: default avatarVignesh R <vigneshr@ti.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0549a3c0

Documentation/dev-tools/kmemleak.rst

+9 −0
Original line number Diff line number Diff line
@@ -162,6 +162,15 @@ See the include/linux/kmemleak.h header for the functions prototype. 
- ``kmemleak_alloc_recursive`` - as kmemleak_alloc but checks the recursiveness

- ``kmemleak_free_recursive``	 - as kmemleak_free but checks the recursiveness



The following functions take a physical address as the object pointer

and only perform the corresponding action if the address has a lowmem

mapping:



- ``kmemleak_alloc_phys``

- ``kmemleak_free_part_phys``

- ``kmemleak_not_leak_phys``

- ``kmemleak_ignore_phys``



Dealing with false positives/negatives

--------------------------------------

include/linux/kmemleak.h

+18 −0
Original line number Diff line number Diff line
@@ -38,6 +38,11 @@ extern void kmemleak_not_leak(const void *ptr) __ref; 
extern void kmemleak_ignore(const void *ptr) __ref;

extern void kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) __ref;

extern void kmemleak_no_scan(const void *ptr) __ref;

extern void kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,

				gfp_t gfp) __ref;

extern void kmemleak_free_part_phys(phys_addr_t phys, size_t size) __ref;

extern void kmemleak_not_leak_phys(phys_addr_t phys) __ref;

extern void kmemleak_ignore_phys(phys_addr_t phys) __ref;



static inline void kmemleak_alloc_recursive(const void *ptr, size_t size,

					    int min_count, unsigned long flags,
@@ -106,6 +111,19 @@ static inline void kmemleak_erase(void **ptr) 
static inline void kmemleak_no_scan(const void *ptr)

{

}

static inline void kmemleak_alloc_phys(phys_addr_t phys, size_t size,

				       int min_count, gfp_t gfp)

{

}

static inline void kmemleak_free_part_phys(phys_addr_t phys, size_t size)

{

}

static inline void kmemleak_not_leak_phys(phys_addr_t phys)

{

}

static inline void kmemleak_ignore_phys(phys_addr_t phys)

{

}



#endif	/* CONFIG_DEBUG_KMEMLEAK */

mm/bootmem.c

+3 −3
Original line number Diff line number Diff line
@@ -155,7 +155,7 @@ void __init free_bootmem_late(unsigned long physaddr, unsigned long size) 
{

	unsigned long cursor, end;



	kmemleak_free_part(__va(physaddr), size);

	kmemleak_free_part_phys(physaddr, size);



	cursor = PFN_UP(physaddr);

	end = PFN_DOWN(physaddr + size);
@@ -399,7 +399,7 @@ void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr, 
{

	unsigned long start, end;



	kmemleak_free_part(__va(physaddr), size);

	kmemleak_free_part_phys(physaddr, size);



	start = PFN_UP(physaddr);

	end = PFN_DOWN(physaddr + size);
@@ -420,7 +420,7 @@ void __init free_bootmem(unsigned long physaddr, unsigned long size) 
{

	unsigned long start, end;



	kmemleak_free_part(__va(physaddr), size);

	kmemleak_free_part_phys(physaddr, size);



	start = PFN_UP(physaddr);

	end = PFN_DOWN(physaddr + size);

mm/cma.c

+1 −1
Original line number Diff line number Diff line
@@ -336,7 +336,7 @@ int __init cma_declare_contiguous(phys_addr_t base, 
		 * kmemleak scans/reads tracked objects for pointers to other

		 * objects but this address isn't mapped and accessible

		 */

		kmemleak_ignore(phys_to_virt(addr));

		kmemleak_ignore_phys(addr);

		base = addr;

	}

mm/kmemleak.c

+47 −0
Original line number Diff line number Diff line
@@ -90,6 +90,8 @@ 
#include <linux/cache.h>

#include <linux/percpu.h>

#include <linux/hardirq.h>

#include <linux/bootmem.h>

#include <linux/pfn.h>

#include <linux/mmzone.h>

#include <linux/slab.h>

#include <linux/thread_info.h>
@@ -1121,6 +1123,51 @@ void __ref kmemleak_no_scan(const void *ptr) 
}

EXPORT_SYMBOL(kmemleak_no_scan);



/**

 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical

 *			 address argument

 */

void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,

			       gfp_t gfp)

{

	if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)

		kmemleak_alloc(__va(phys), size, min_count, gfp);

}

EXPORT_SYMBOL(kmemleak_alloc_phys);



/**

 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a

 *			     physical address argument

 */

void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)

{

	if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)

		kmemleak_free_part(__va(phys), size);

}

EXPORT_SYMBOL(kmemleak_free_part_phys);



/**

 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical

 *			    address argument

 */

void __ref kmemleak_not_leak_phys(phys_addr_t phys)

{

	if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)

		kmemleak_not_leak(__va(phys));

}

EXPORT_SYMBOL(kmemleak_not_leak_phys);



/**

 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical

 *			  address argument

 */

void __ref kmemleak_ignore_phys(phys_addr_t phys)

{

	if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)

		kmemleak_ignore(__va(phys));

}

EXPORT_SYMBOL(kmemleak_ignore_phys);



/*

 * Update an object's checksum and return true if it was modified.

 */

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