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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: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Michal Hocko 2017-05-08 15:57:12 -07:00 committed by Linus Torvalds
parent a7c3e901a4
commit 1f5307b1e0
2 changed files with 20 additions and 11 deletions
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19
include/linux/vmalloc.h
View File

@ -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);

12
mm/vmalloc.c
View File

@ -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 @@ fail:
* 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