lazy ksymbols: fix address search #283
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What about to sort |
In addition to that possibility, I think that, in the future, we can refactor a bit by moving some of the parsing logic into a function. |
NDStrahilevitz
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geyslan
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Jan 5, 2023
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Could you explain better in the git log what was the fix you did with this commit? Also, you recommended a PR in tracee to use lazy symbols, if it is broken it is better to update that PR as well (asking for the author to include this fix). Thanks! |
rafaeldtinoco
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In commit 3ea9231, a new KernelSymbolsTable implementation was added which uses lazy querying and parsing of a stored string copy of the /proc/kallsyms file. In order to keep efficiency of non cached queries, binary search was used for querying symbols by address, since the file mostly stores the symbols in order of addresses. However, on kernels compiled with CONFIG_KALLSYMS_ALL=y, symbols from other sections may be present in a non ordered place. This wasn't taken in consideration in initial implementations, and so a query by address could have failed despite existing. These symbols usually appear near the end of the file, so a reverse linear search is added after a failed binary search.
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ksymbols may sometimes not be sorted at the edges, usually for non system symbols. As such searching by binary search may fail. Add a reverse linear search at the end to catch these symbols.