lower_half/mmap64.c: mmaps[]: add sentinel #351
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| for (int i = 0; i < numRegions; i++) { | ||
| for (int i = 0; i < numMmapRegions; i++) { | ||
| memset(&mmaps[i], 0, sizeof(mmaps[i])); | ||
| mmaps[i].addr = MAP_FAILED; // Mark those mmaps past numMmapRegions, for GDB |
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memset should take care of setting all the variables to 0x0. We do not need to set MAP_FAILED separately. Also, the comment does not reflect the code. The loop is only till numMmapRegions, not past that.
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Did you mean to add MAP_FAILED after the for loop? The value of i would then be numMmapRegions.
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| for (int i = 0; i < numRegions; i++) { | ||
| for (int i = 0; i < numMmapRegions; i++) { | ||
| memset(&mmaps[i], 0, sizeof(mmaps[i])); | ||
| mmaps[i].addr = MAP_FAILED; // Mark those mmaps past numMmapRegions, for GDB |
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Did you mean to add MAP_FAILED after the for loop? The value of i would then be numMmapRegions.
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@JainTwinkle, Thanks for the comment about:
Good catch! I've now changed it to set the 'addr' to MAP_FAILED for all mmaps elements. Since 'numMmapRegions' is 0 at the end, I could set it just for the zero-th element. But it's safer to set it for all 'mmaps' elements. |
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This adds a sentinel (MAP_FAILED) to the mmaps[] array, and then checks for it in the mpi_plugin.cpp:DMTCP_EVENT_PRECHECKPOINT.
It also renames numRegions to numMmapRegions in lower_half, and improves the documentation in mmap64.c where we reserve a large mmap'ed region for mmap64.c,, starting at 0x2aab00000000;.