Protect patching with an open handle #1264
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…as the originally discovered lib in maps
Signed-off-by: Bara' Hasheesh <[email protected]>
# Conflicts: # src/symbols_linux.cpp
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Tested that after this PR the test in asprof-reproducers does not fail anymore, and fails in |
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Also tested the crash in the stress test by @Baraa-Hasheesh, and could not reproduce the issue anymore after this PR |
Co-authored-by: Bara' Hasheesh <[email protected]> Signed-off-by: Francesco Andreuzzi <[email protected]>
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Let's add minimal reproducers as cpp unit tests. |
@krk Adapted test from @Baraa-Hasheesh's repo |
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src/symbols_linux.cpp
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| // Protect library from unloading while parsing in-memory ELF program headers. | ||
| // Also, dlopen() ensures the library is fully loaded. | ||
| _lib_handle = dlopen(stripped_name, RTLD_LAZY | RTLD_NOLOAD); | ||
| _valid = isValidHandle(cc, _lib_handle); |
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Not the best name, IMO.
Any non-null handle is valid, but what we really check here is whether it is the same shared library that was seen at CodeCache creation time.
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checkHandleConsistencyisHandleConsistent
I'll think about it, let me know if you have any preference
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@apangin all comments addressed |
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100 commits, 140 comments, 5 contributors. That was an epic PR. Thanks everyone involved! |
Description
In this PR I introduce additional protection during patches. The main change is a new function
isSafeToPatch, which combines the checks introduced in #1261, #1263, #1243, and can be used in other parts of the code likeMallocTracer.Thanks @Baraa-Hasheesh for the discussion and feedback on the code.
Related issues
#1250, #1256
Motivation and context
Keeping an open handle makes sure we the library cannot be unloaded while the patch is being made, thus providing additional protection against the failures in the linked issues.
How has this been tested?
make testBy submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.