Pass text segment info to GetBase to handle Linux kernel ASLR case. #299
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When pprof symbolizes kernel addresses in vmlinux binary for a profile converted using https://github.com/google/perf_data_converter, the addresses need to be adjusted if kernel ASLR is in effect. So far the call to GetBase did not pass text segment info to GetBase which shortcircuited the code to merely return zero adjustment. This change fixes the call to GetBase to address that. The added test case is a simulation of what happens with vmlinux, but it should be pretty close. Including a vmlinux file into the test data does not appear practical due to the binary size. I verified that the test failed before the fix and passes after. Note that the fixed issue is specific to the kernel ASLR as user-mode ASRL-enabled binaries (i.e. built with -pie / -fpie) have ET_DYN type which takes a different code path in GetBase which did not have issues before this fix in practice.
Codecov Report
@@ Coverage Diff @@
## master #299 +/- ##
==========================================
- Coverage 65.85% 65.81% -0.04%
==========================================
Files 36 36
Lines 7388 7395 +7
==========================================
+ Hits 4865 4867 +2
- Misses 2128 2133 +5
Partials 395 395
Continue to review full report at Codecov.
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rauls5382
approved these changes
Jan 29, 2018
lannadorai
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Feb 13, 2018
…oogle#299) When pprof symbolizes kernel addresses in vmlinux binary for a profile converted using https://github.com/google/perf_data_converter, the addresses need to be adjusted if kernel ASLR is in effect. So far the call to GetBase did not pass text segment info to GetBase which shortcircuited the code to merely return zero adjustment. This change fixes the call to GetBase to address that. The added test case is a simulation of what happens with vmlinux, but it should be pretty close. Including a vmlinux file into the test data does not appear practical due to the binary size. I verified that the test failed before the fix and passes after. Note that the fixed issue is specific to the kernel ASLR as user-mode ASRL-enabled binaries (i.e. built with -pie / -fpie) have ET_DYN type which takes a different code path in GetBase which did not have issues before this fix in practice.
gmarin13
pushed a commit
to gmarin13/pprof
that referenced
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Dec 17, 2020
…oogle#299) When pprof symbolizes kernel addresses in vmlinux binary for a profile converted using https://github.com/google/perf_data_converter, the addresses need to be adjusted if kernel ASLR is in effect. So far the call to GetBase did not pass text segment info to GetBase which shortcircuited the code to merely return zero adjustment. This change fixes the call to GetBase to address that. The added test case is a simulation of what happens with vmlinux, but it should be pretty close. Including a vmlinux file into the test data does not appear practical due to the binary size. I verified that the test failed before the fix and passes after. Note that the fixed issue is specific to the kernel ASLR as user-mode ASRL-enabled binaries (i.e. built with -pie / -fpie) have ET_DYN type which takes a different code path in GetBase which did not have issues before this fix in practice.
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When pprof symbolizes kernel addresses in vmlinux binary for a profile
converted using https://github.com/google/perf_data_converter, the
addresses need to be adjusted if kernel ASLR is in effect. So far the
call to GetBase did not pass text segment info to GetBase which
shortcircuited the code to merely return zero adjustment. This change
fixes the call to GetBase to address that.
The added test case is an approximation of what happens with vmlinux,
but it should be pretty close. Including a vmlinux file into the test data
does not appear practical due to the binary size. I verified that the test
failed before the fix and passes after.
Note that the fixed issue is specific to the kernel ASLR as user-mode
ASRL-enabled binaries (i.e. built with -pie / -fpie) have ET_DYN type
which takes a different code path in GetBase which did not have issues
before this fix in practice.