Memory Leak (Regions)
The set of memory dumps that prompted to introduce Insufficient Memory pattern for stack trace database (page 57) also prompted to include a variant of Memory Leak pattern related to regions of virtual memory address space. We created this simple modeling application:
int _tmain(int argc, _TCHAR* argv[])
{
int i,j;
for (i = 1; i < 1000; ++i)
{
for (j = 1; j < 1000; ++j)
{
VirtualAlloc(NULL, 0x10000, MEM_RESERVE,
PAGE_EXECUTE_READWRITE);
}
getc(stdin);
}
return 0;
}
We allocated only reserved memory regions. Committing them would probably at some stage manifest Insufficient Memory patterns for committed memory (Volume 1, page 302) and physical memory (Volume 3, page 104). So we took a few consecutive memory dumps and saw the ever increasing number of regions allocated at greater and greater virtual addresses:
0:000> !address [...] * 0`04070000 0`04080000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`04080000 0`04090000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`04090000 0`040a0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`040a0000 0`040b0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`040b0000 0`040c0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`040c0000 0`040d0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`040d0000 0`040e0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`040e0000 0`040f0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`040f0000 0`04100000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`04100000 0`04110000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`04110000 0`04120000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`04120000 0`04130000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`04130000 0`04140000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`04140000 0`04260000 0`00120000 MEM_FREE PAGE_NOACCES S Free [...] 0:000> !address [...] * 0`2eec0000 0`2eed0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2eed0000 0`2eee0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2eee0000 0`2eef0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2eef0000 0`2ef00000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef00000 0`2ef10000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef10000 0`2ef20000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef20000 0`2ef30000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef30000 0`2ef40000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef40000 0`2ef50000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef50000 0`2ef60000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef60000 0`2ef70000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef70000 0`2ef80000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef80000 0`2ef90000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2ef90000 0`2efa0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2efa0000 0`2efb0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2efb0000 0`2efc0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2efc0000 0`2efd0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2efd0000 0`2efe0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2efe0000 0`2eff0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2eff0000 0`2f000000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2f000000 0`2f010000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`2f010000 0`2f170000 0`00160000 MEM_FREE PAGE_NOACCES S Free [...] 0:000> !address [...] * 0`697f0000 0`69800000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69800000 0`69810000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69810000 0`69820000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69820000 0`69830000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69830000 0`69840000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69840000 0`69850000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69850000 0`69860000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69860000 0`69870000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69870000 0`69880000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69880000 0`69890000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`69890000 0`698a0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`698a0000 0`699e0000 0`00140000 MEM_FREE PAGE_NOACCES S Free [...] 0:000> !address [...] * 0`c08c0000 0`c08d0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`c08d0000 0`c08e0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`c08e0000 0`c08f0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`c08f0000 0`c0900000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`c0900000 0`c0910000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`c0910000 0`c0920000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`c0920000 0`c0930000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 0`c0930000 0`c0960000 0`00030000 MEM_FREE PAGE_NOACCES S Free [...] 0:000> !address [...] * 1`3d6a0000 1`3d6b0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d6b0000 1`3d6c0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d6c0000 1`3d6d0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d6d0000 1`3d6e0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d6e0000 1`3d6f0000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d6f0000 1`3d700000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d700000 1`3d710000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d710000 1`3d720000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d720000 1`3d730000 0`00010000 MEM_PRIVATE MEM_RESERVE <unclassified> * 1`3d730000 1`3d7a0000 0`00070000 MEM_FREE PAGE_NOACCES S Free [...] 0:000> !address -summary --- Usage Summary ---------------- RgnCount ---- Total Size --- %ofBusy %ofTotal Free 15 7fe`c275e000 ( 7.995 Tb) 99.94% <unclassified> 80928 1`3d193000 ( 4.955 Gb) 99.86% 0.06% Image 28 0`0034b000 ( 3.293 Mb) 0.06% 0.00% Stack 6 0`00200000 ( 2.000 Mb) 0.04% 0.00% MemoryMappedFile 8 0`001af000 ( 1.684 Mb) 0.03% 0.00% TEB 2 0`00004000 ( 16.000 kb) 0.00% 0.00% PEB 1 0`00001000 ( 4.000 kb) 0.00% 0.00% --- Type Summary (for busy) ------ RgnCount ----------- Total Size -------- %ofBusy %ofTotal MEM_PRIVATE 80936 1`3d397000 ( 4.957 Gb) 99.90% 0.06% MEM_IMAGE 29 0`0034c000 ( 3.297 Mb) 0.06% 0.00% MEM_MAPPED 8 0`001af000 ( 1.684 Mb) 0.03% 0.00% --- State Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal MEM_FREE 15 7fe`c275e000 ( 7.995 Tb) 99.94% MEM_RESERVE 80926 1`3d438000 ( 4.957 Gb) 99.91% 0.06% MEM_COMMIT 47 0`0045a000 ( 4.352 Mb) 0.09% 0.00% --- Protect Summary (for commit) - RgnCount ----------- Total Size -------- %ofBusy %ofTotal PAGE_EXECUTE_READ 4 0`001ef000 ( 1.934 Mb) 0.04% 0.00% PAGE_READONLY 19 0`001de000 ( 1.867 Mb) 0.04% 0.00% PAGE_READWRITE 17 0`00080000 ( 512.000 kb) 0.01% 0.00% PAGE_WRITECOPY 5 0`00008000 ( 32.000 kb) 0.00% 0.00% PAGE_READWRITE|PAGE_GUARD 2 0`00005000 ( 20.000 kb) 0.00% 0.00% --- Largest Region by Usage ----------- Base Address -------- Region Size ---------- Free 1`3fac7000 7fd`bdc79000 ( 7.991 Tb) <unclassified> 0`7f0e0000 0`00f00000 ( 15.000 Mb) Image 0`77831000 0`00102000 ( 1.008 Mb) Stack 0`00170000 0`000fb000 (1004.000 kb) MemoryMappedFile 0`7efe5000 0`000fb000 (1004.000 kb) TEB 7ff`fffdc000 0`00002000 ( 8.000 kb) PEB 7ff`fffd3000 0`00001000 ( 4.000 kb)
Examination of such regions for Execution Residue (Volume 2, page 239) such as Module Hint (Volume 6, page 92) may point into further troubleshooting directions especially if live debugging is not possible.
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