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Commitbfd12cc

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committed
Make useful infrastructure from aset.c generally available.
An upcoming patch introduces a new type of memory context. To avoidduplicating debugging infrastructure within aset.c, move useful piecesto memdebug.[ch].While touching aset.c, fix printf format code in AllocFree* debugmacros.Author: Tomas VondraReviewed-By: Andres FreundDiscussion:https://postgr.es/m/b3b2245c-b37a-e1e5-ebc4-857c914bc747@2ndquadrant.com
1 parent1513dbe commitbfd12cc

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4 files changed

+144
-114
lines changed

4 files changed

+144
-114
lines changed

‎src/backend/utils/mmgr/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -12,6 +12,6 @@ subdir = src/backend/utils/mmgr
1212
top_builddir = ../../../..
1313
include$(top_builddir)/src/Makefile.global
1414

15-
OBJS = aset.o dsa.o freepage.o mcxt.o portalmem.o
15+
OBJS = aset.o dsa.o freepage.o mcxt.omemdebug.oportalmem.o
1616

1717
include$(top_srcdir)/src/backend/common.mk

‎src/backend/utils/mmgr/aset.c

Lines changed: 2 additions & 113 deletions
Original file line numberDiff line numberDiff line change
@@ -41,46 +41,6 @@
4141
*chunks as chunks. Anything "large" is passed off to malloc(). Change
4242
*the number of freelists to change the small/large boundary.
4343
*
44-
*
45-
*About CLOBBER_FREED_MEMORY:
46-
*
47-
*If this symbol is defined, all freed memory is overwritten with 0x7F's.
48-
*This is useful for catching places that reference already-freed memory.
49-
*
50-
*About MEMORY_CONTEXT_CHECKING:
51-
*
52-
*Since we usually round request sizes up to the next power of 2, there
53-
*is often some unused space immediately after a requested data area.
54-
*Thus, if someone makes the common error of writing past what they've
55-
*requested, the problem is likely to go unnoticed ... until the day when
56-
*there *isn't* any wasted space, perhaps because of different memory
57-
*alignment on a new platform, or some other effect. To catch this sort
58-
*of problem, the MEMORY_CONTEXT_CHECKING option stores 0x7E just beyond
59-
*the requested space whenever the request is less than the actual chunk
60-
*size, and verifies that the byte is undamaged when the chunk is freed.
61-
*
62-
*
63-
*About USE_VALGRIND and Valgrind client requests:
64-
*
65-
*Valgrind provides "client request" macros that exchange information with
66-
*the host Valgrind (if any). Under !USE_VALGRIND, memdebug.h stubs out
67-
*currently-used macros.
68-
*
69-
*When running under Valgrind, we want a NOACCESS memory region both before
70-
*and after the allocation. The chunk header is tempting as the preceding
71-
*region, but mcxt.c expects to able to examine the standard chunk header
72-
*fields. Therefore, we use, when available, the requested_size field and
73-
*any subsequent padding. requested_size is made NOACCESS before returning
74-
*a chunk pointer to a caller. However, to reduce client request traffic,
75-
*it is kept DEFINED in chunks on the free list.
76-
*
77-
*The rounded-up capacity of the chunk usually acts as a post-allocation
78-
*NOACCESS region. If the request consumes precisely the entire chunk,
79-
*there is no such region; another chunk header may immediately follow. In
80-
*that case, Valgrind will not detect access beyond the end of the chunk.
81-
*
82-
*See also the cooperating Valgrind client requests in mcxt.c.
83-
*
8444
*-------------------------------------------------------------------------
8545
*/
8646

@@ -296,10 +256,10 @@ static const unsigned char LogTable256[256] =
296256
*/
297257
#ifdefHAVE_ALLOCINFO
298258
#defineAllocFreeInfo(_cxt,_chunk) \
299-
fprintf(stderr, "AllocFree: %s: %p, %d\n", \
259+
fprintf(stderr, "AllocFree: %s: %p, %zu\n", \
300260
(_cxt)->header.name, (_chunk), (_chunk)->size)
301261
#defineAllocAllocInfo(_cxt,_chunk) \
302-
fprintf(stderr, "AllocAlloc: %s: %p, %d\n", \
262+
fprintf(stderr, "AllocAlloc: %s: %p, %zu\n", \
303263
(_cxt)->header.name, (_chunk), (_chunk)->size)
304264
#else
305265
#defineAllocFreeInfo(_cxt,_chunk)
@@ -345,77 +305,6 @@ AllocSetFreeIndex(Size size)
345305
returnidx;
346306
}
347307

348-
#ifdefCLOBBER_FREED_MEMORY
349-
350-
/* Wipe freed memory for debugging purposes */
351-
staticvoid
352-
wipe_mem(void*ptr,size_tsize)
353-
{
354-
VALGRIND_MAKE_MEM_UNDEFINED(ptr,size);
355-
memset(ptr,0x7F,size);
356-
VALGRIND_MAKE_MEM_NOACCESS(ptr,size);
357-
}
358-
#endif
359-
360-
#ifdefMEMORY_CONTEXT_CHECKING
361-
staticvoid
362-
set_sentinel(void*base,Sizeoffset)
363-
{
364-
char*ptr= (char*)base+offset;
365-
366-
VALGRIND_MAKE_MEM_UNDEFINED(ptr,1);
367-
*ptr=0x7E;
368-
VALGRIND_MAKE_MEM_NOACCESS(ptr,1);
369-
}
370-
371-
staticbool
372-
sentinel_ok(constvoid*base,Sizeoffset)
373-
{
374-
constchar*ptr= (constchar*)base+offset;
375-
boolret;
376-
377-
VALGRIND_MAKE_MEM_DEFINED(ptr,1);
378-
ret=*ptr==0x7E;
379-
VALGRIND_MAKE_MEM_NOACCESS(ptr,1);
380-
381-
returnret;
382-
}
383-
#endif
384-
385-
#ifdefRANDOMIZE_ALLOCATED_MEMORY
386-
387-
/*
388-
* Fill a just-allocated piece of memory with "random" data. It's not really
389-
* very random, just a repeating sequence with a length that's prime. What
390-
* we mainly want out of it is to have a good probability that two palloc's
391-
* of the same number of bytes start out containing different data.
392-
*
393-
* The region may be NOACCESS, so make it UNDEFINED first to avoid errors as
394-
* we fill it. Filling the region makes it DEFINED, so make it UNDEFINED
395-
* again afterward. Whether to finally make it UNDEFINED or NOACCESS is
396-
* fairly arbitrary. UNDEFINED is more convenient for AllocSetRealloc(), and
397-
* other callers have no preference.
398-
*/
399-
staticvoid
400-
randomize_mem(char*ptr,size_tsize)
401-
{
402-
staticintsave_ctr=1;
403-
size_tremaining=size;
404-
intctr;
405-
406-
ctr=save_ctr;
407-
VALGRIND_MAKE_MEM_UNDEFINED(ptr,size);
408-
while (remaining-->0)
409-
{
410-
*ptr++=ctr;
411-
if (++ctr>251)
412-
ctr=1;
413-
}
414-
VALGRIND_MAKE_MEM_UNDEFINED(ptr-size,size);
415-
save_ctr=ctr;
416-
}
417-
#endif/* RANDOMIZE_ALLOCATED_MEMORY */
418-
419308

420309
/*
421310
* Public routines

‎src/backend/utils/mmgr/memdebug.c

Lines changed: 93 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,93 @@
1+
/*-------------------------------------------------------------------------
2+
*
3+
* memdebug.c
4+
* Declarations used in memory context implementations, not part of the
5+
* public API of the memory management subsystem.
6+
*
7+
*
8+
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
9+
* Portions Copyright (c) 1994, Regents of the University of California
10+
*
11+
* src/backend/utils/memdebug.c
12+
*
13+
*
14+
*About CLOBBER_FREED_MEMORY:
15+
*
16+
*If this symbol is defined, all freed memory is overwritten with 0x7F's.
17+
*This is useful for catching places that reference already-freed memory.
18+
*
19+
*About MEMORY_CONTEXT_CHECKING:
20+
*
21+
*Since we usually round request sizes up to the next power of 2, there
22+
*is often some unused space immediately after a requested data area.
23+
*Thus, if someone makes the common error of writing past what they've
24+
*requested, the problem is likely to go unnoticed ... until the day when
25+
*there *isn't* any wasted space, perhaps because of different memory
26+
*alignment on a new platform, or some other effect. To catch this sort
27+
*of problem, the MEMORY_CONTEXT_CHECKING option stores 0x7E just beyond
28+
*the requested space whenever the request is less than the actual chunk
29+
*size, and verifies that the byte is undamaged when the chunk is freed.
30+
*
31+
*
32+
*About USE_VALGRIND and Valgrind client requests:
33+
*
34+
*Valgrind provides "client request" macros that exchange information with
35+
*the host Valgrind (if any). Under !USE_VALGRIND, memdebug.h stubs out
36+
*currently-used macros.
37+
*
38+
*When running under Valgrind, we want a NOACCESS memory region both before
39+
*and after the allocation. The chunk header is tempting as the preceding
40+
*region, but mcxt.c expects to able to examine the standard chunk header
41+
*fields. Therefore, we use, when available, the requested_size field and
42+
*any subsequent padding. requested_size is made NOACCESS before returning
43+
*a chunk pointer to a caller. However, to reduce client request traffic,
44+
*it is kept DEFINED in chunks on the free list.
45+
*
46+
*The rounded-up capacity of the chunk usually acts as a post-allocation
47+
*NOACCESS region. If the request consumes precisely the entire chunk,
48+
*there is no such region; another chunk header may immediately follow. In
49+
*that case, Valgrind will not detect access beyond the end of the chunk.
50+
*
51+
*See also the cooperating Valgrind client requests in mcxt.c.
52+
*
53+
*-------------------------------------------------------------------------
54+
*/
55+
56+
#include"postgres.h"
57+
58+
#include"utils/memdebug.h"
59+
60+
#ifdefRANDOMIZE_ALLOCATED_MEMORY
61+
62+
/*
63+
* Fill a just-allocated piece of memory with "random" data. It's not really
64+
* very random, just a repeating sequence with a length that's prime. What
65+
* we mainly want out of it is to have a good probability that two palloc's
66+
* of the same number of bytes start out containing different data.
67+
*
68+
* The region may be NOACCESS, so make it UNDEFINED first to avoid errors as
69+
* we fill it. Filling the region makes it DEFINED, so make it UNDEFINED
70+
* again afterward. Whether to finally make it UNDEFINED or NOACCESS is
71+
* fairly arbitrary. UNDEFINED is more convenient for SlabRealloc(), and
72+
* other callers have no preference.
73+
*/
74+
void
75+
randomize_mem(char*ptr,size_tsize)
76+
{
77+
staticintsave_ctr=1;
78+
size_tremaining=size;
79+
intctr;
80+
81+
ctr=save_ctr;
82+
VALGRIND_MAKE_MEM_UNDEFINED(ptr,size);
83+
while (remaining-->0)
84+
{
85+
*ptr++=ctr;
86+
if (++ctr>251)
87+
ctr=1;
88+
}
89+
VALGRIND_MAKE_MEM_UNDEFINED(ptr-size,size);
90+
save_ctr=ctr;
91+
}
92+
93+
#endif/* RANDOMIZE_ALLOCATED_MEMORY */

‎src/include/utils/memdebug.h

Lines changed: 48 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -31,4 +31,52 @@
3131
#defineVALGRIND_MEMPOOL_CHANGE(context,optr,nptr,size)do {} while (0)
3232
#endif
3333

34+
35+
#ifdefCLOBBER_FREED_MEMORY
36+
37+
/* Wipe freed memory for debugging purposes */
38+
staticinlinevoid
39+
wipe_mem(void*ptr,size_tsize)
40+
{
41+
VALGRIND_MAKE_MEM_UNDEFINED(ptr,size);
42+
memset(ptr,0x7F,size);
43+
VALGRIND_MAKE_MEM_NOACCESS(ptr,size);
44+
}
45+
46+
#endif/* CLOBBER_FREED_MEMORY */
47+
48+
#ifdefMEMORY_CONTEXT_CHECKING
49+
50+
staticinlinevoid
51+
set_sentinel(void*base,Sizeoffset)
52+
{
53+
char*ptr= (char*)base+offset;
54+
55+
VALGRIND_MAKE_MEM_UNDEFINED(ptr,1);
56+
*ptr=0x7E;
57+
VALGRIND_MAKE_MEM_NOACCESS(ptr,1);
58+
}
59+
60+
staticinlinebool
61+
sentinel_ok(constvoid*base,Sizeoffset)
62+
{
63+
constchar*ptr= (constchar*)base+offset;
64+
boolret;
65+
66+
VALGRIND_MAKE_MEM_DEFINED(ptr,1);
67+
ret=*ptr==0x7E;
68+
VALGRIND_MAKE_MEM_NOACCESS(ptr,1);
69+
70+
returnret;
71+
}
72+
73+
#endif/* MEMORY_CONTEXT_CHECKING */
74+
75+
#ifdefRANDOMIZE_ALLOCATED_MEMORY
76+
77+
voidrandomize_mem(char*ptr,size_tsize);
78+
79+
#endif/* RANDOMIZE_ALLOCATED_MEMORY */
80+
81+
3482
#endif/* MEMDEBUG_H */

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