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Commit 1f5307b1 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
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mm, vmalloc: properly track vmalloc users 

__vmalloc_node_flags used to be static inline but this has changed by
"mm: introduce kv[mz]alloc helpers" because kvmalloc_node needs to use
it as well and the code is outside of the vmalloc proper.  I haven't
realized that changing this will lead to a subtle bug though.  The
function is responsible to track the caller as well.  This caller is
then printed by /proc/vmallocinfo.  If __vmalloc_node_flags is not
inline then we would get only direct users of __vmalloc_node_flags as
callers (e.g.  v[mz]alloc) which reduces usefulness of this debugging
feature considerably.  It simply doesn't help to see that the given
range belongs to vmalloc as a caller:

  0xffffc90002c79000-0xffffc90002c7d000   16384 vmalloc+0x16/0x18 pages=3 vmalloc N0=3
  0xffffc90002c81000-0xffffc90002c85000   16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3
  0xffffc90002c8d000-0xffffc90002c91000   16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3
  0xffffc90002c95000-0xffffc90002c99000   16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3

We really want to catch the _caller_ of the vmalloc function.  Fix this
issue by making __vmalloc_node_flags static inline again.

Link: http://lkml.kernel.org/r/20170502134657.12381-1-mhocko@kernel.org


Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a7c3e901

include/linux/vmalloc.h

+19 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/list.h>

#include <linux/llist.h>

#include <asm/page.h>		/* pgprot_t */

#include <asm/pgtable.h>	/* PAGE_KERNEL */

#include <linux/rbtree.h>



struct vm_area_struct;		/* vma defining user mapping in mm_types.h */
@@ -80,7 +81,25 @@ extern void *__vmalloc_node_range(unsigned long size, unsigned long align, 
			unsigned long start, unsigned long end, gfp_t gfp_mask,

			pgprot_t prot, unsigned long vm_flags, int node,

			const void *caller);

#ifndef CONFIG_MMU

extern void *__vmalloc_node_flags(unsigned long size, int node, gfp_t flags);

#else

extern void *__vmalloc_node(unsigned long size, unsigned long align,

			    gfp_t gfp_mask, pgprot_t prot,

			    int node, const void *caller);



/*

 * We really want to have this inlined due to caller tracking. This

 * function is used by the highlevel vmalloc apis and so we want to track

 * their callers and inlining will achieve that.

 */

static inline void *__vmalloc_node_flags(unsigned long size,

					int node, gfp_t flags)

{

	return __vmalloc_node(size, 1, flags, PAGE_KERNEL,

					node, __builtin_return_address(0));

}

#endif



extern void vfree(const void *addr);

extern void vfree_atomic(const void *addr);

mm/vmalloc.c

+1 −11
Original line number Diff line number Diff line
@@ -1649,9 +1649,6 @@ void *vmap(struct page **pages, unsigned int count, 
}

EXPORT_SYMBOL(vmap);



static void *__vmalloc_node(unsigned long size, unsigned long align,

			    gfp_t gfp_mask, pgprot_t prot,

			    int node, const void *caller);

static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,

				 pgprot_t prot, int node)

{
@@ -1794,7 +1791,7 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, 
 *	with mm people.

 *

 */

static void *__vmalloc_node(unsigned long size, unsigned long align,

void *__vmalloc_node(unsigned long size, unsigned long align,

			    gfp_t gfp_mask, pgprot_t prot,

			    int node, const void *caller)

{
@@ -1809,13 +1806,6 @@ void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) 
}

EXPORT_SYMBOL(__vmalloc);



void *__vmalloc_node_flags(unsigned long size,

					int node, gfp_t flags)

{

	return __vmalloc_node(size, 1, flags, PAGE_KERNEL,

					node, __builtin_return_address(0));

}



/**

 *	vmalloc  -  allocate virtually contiguous memory

 *	@size:		allocation size