#1250 validate that the obtained dlopen handle is same as the originally discovered lib in maps #1261
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…as the originally discovered lib in maps
krk
suggested changes
Apr 24, 2025
src/symbols_linux.cpp
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| // Also, dlopen() ensures the library is fully loaded. | ||
| // Main executable and ld-linux interpreter cannot be dlopen'ed, but dlerror() returns NULL for them on some systems. | ||
| void* handle = dlopen(lib.file, RTLD_LAZY | RTLD_NOLOAD); | ||
| bool valid_handle = false; |
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If handle is not null, it is valid. I would rename the variable to reflect intent: "handle is to a different instance of the shared object, compared to what was parsed from /maps".
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renamed to original_handle
Signed-off-by: Bara' Hasheesh <bara.hasheesh@gmail.com>
apangin
reviewed
Apr 24, 2025
src/symbols_linux.cpp
Outdated
| // Parse main executable regardless of dlopen result, since it cannot be unloaded. | ||
| bool is_main_exe = main_phdr >= lib.image_base && main_phdr < lib.map_end; | ||
| if (handle != NULL || dlerror() == NULL || is_main_exe) { | ||
| if (original_handle || dlerror() == NULL || is_main_exe) { |
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This is not correct: because of "dlerror() == NULL", condition will be still true, even if base address differs.
Fortunately, dlerror() should go away after Kerem's fix.
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That's correct
@krk change is required here
I will sync & resolve conflicts
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@apangin branch synced & conflicts handled
# Conflicts: # src/symbols_linux.cpp
krk
approved these changes
Apr 25, 2025
|
included here #1264 |
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Description
This fixes fixes one of the potential problems discovered in the #1250
This change detects if the library was reloaded to a different location & marks the handle as invalid
Note: This solution isn't complete & needs to change handling of
dlerror() == nullto only be valid forldlibraryRelated issues
#1250
Motivation and context
Reduce effect of race conditions to async profiler
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.