-
Type:
Task
-
Resolution: Done
-
Priority:
Major - P3
-
None
-
Affects Version/s: None
-
Component/s: None
-
Labels:
-
Server Development Platform
-
Fully Compatible
-
Dev Platform 2021-08-23, Dev Platform 2021-09-20, Dev Platform 2021-10-04, Dev Platform 2021-10-18, Dev Platform 2021-11-29
The toolchain gcc generated debug symbols can't be read entirely by the toolchain's llvm-symbolizer; there are line numbers missing and maybe other issues. This is possibly only affecting statically linked binaries as some shared library builds and possibly only mongod. Static mongos and shared libraries seem to be fine.
Using llvm-symbolizer-10 and above works. Drew tried 10 and I tried 12.
Copying some of Drew's research from Slack for context:
Running various versions of llvm-symbolizer
andrew@acm-workstation:~/asdf/dist-test/bin$ time llvm-symbolizer-7 --obj=./mongod <<< 0x2D5A0F0 mongo::LockRequestList::push_back(mongo::LockRequest*) ??:0:0 real 0m0.905s user 0m0.828s sys 0m0.061s andrew@acm-workstation:~/asdf/dist-test/bin$ time llvm-symbolizer-8 --obj=./mongod <<< 0x2D5A0F0 mongo::LockRequestList::push_back(mongo::LockRequest*) ??:0:0 real 0m0.905s user 0m0.816s sys 0m0.073s andrew@acm-workstation:~/asdf/dist-test/bin$ time llvm-symbolizer-9 --obj=./mongod <<< 0x2D5A0F0 mongo::LockRequestList::push_back(mongo::LockRequest*) ??:0:0 real 0m0.889s user 0m0.810s sys 0m0.060s andrew@acm-workstation:~/asdf/dist-test/bin$ time llvm-symbolizer-10 --obj=./mongod <<< 0x2D5A0F0 mongo::LockRequestList::push_back(mongo::LockRequest*) /data/mci/49914e6e89befead31fc1fecb83f2a54/src/src/mongo/db/concurrency/lock_request_list.h:74:25 real 0m7.524s user 0m7.100s sys 0m0.404s
Checking the debug symbols format with dwarfdump:
# mongod # $ dwarfdump -ka ./mongod.debug dwarfdump ERROR: Failure reading CU header or DIE, corrupt DWARF: DW_DLE_READ_ERROR(419). Read failed, corrupt object. Attempting to continue. dwarfdump ERROR: attempting to print .debug_info: DW_DLE_READ_ERROR(419). Read failed, corrupt object (419) attempting to continue. dwarfdump ERROR: dwarf_get_aranges: DW_DLE_READ_ERROR(419). Read failed, corrupt object # mongos *** DWARF CHECK: DW_TAG_enumeration_type -> DW_AT_encoding: check the tag-attr combination *** CU Name = src/mongo/s/mongos.cpp CU Producer = GNU C++17 8.5.0 -march=sandybridge -mtune=generic -mprefer-vector-width=128 -ggdb -O2 -std=c++17 -fsized-deallocation -fasynchronous-unwind-tables -fno-omit-frame-pointer -fno-strict-aliasing -fstack-protector-strong -fno-builtin-memcmp -fPIE DIE OFF = 0x00000036 GOFF = 0x00000036, Low PC = 0x00000000, High PC = unknown DW_AT_encoding DW_ATE_signed *** DWARF CHECK: DW_TAG_enumeration_type -> DW_AT_encoding: check the tag-attr combination ***
readelf seems to work for both mongod and mongos with both showing debug symbols and source files.