Commit Graph

13 Commits

Author SHA1 Message Date
Yong Li fbca300097 Fix GetGlobalVariableOffset with tagged pointer in aarch64
Tagged pointer for aarch64 since Android R would lead top byte to have
random values. For example of a symbol from libart.so in a hwasan
enabled device in Android R:

1490: 8800000000b094a0   144 OBJECT  GLOBAL 24 __dex_debug_descriptor

We need to mask off the top byte so that the address range comparison
would work as intended.

Test: Ran new unit test

Signed-off-by: Yong Li <yongl0722@gmail.com>
Change-Id: Ia8c638e16baff57740c569e9eaf9cfd1f5bd3fad
2020-04-27 21:07:50 +00:00
Christopher Ferris 8726d3a448 Fix handling of possible bad gnu_debugdata_size.
Rather than use a std::vector for backing memory, allocate the memory
using a new with nothrow, and in MemoryBuffer use realloc. Since
the size field is coming from the elf, it could be corrupted or
intentionally crafted to cause problems.

In addition, add some other protections to make sure that overflows
don't occur.

Bug: 146215949

Test: Ran unit tests with jemalloc and scudo to verify that they
Test: both behave the same way.
Change-Id: If14243ce382ba5403a6bacd0ec673452c6b7c3be
2019-12-19 16:48:15 -08:00
Christopher Ferris df683b7439 Fix support finding global variables.
The code was not properly getting the variable addresses and using
the offset and address fields of the .data section.

Fix all of that, and update the tests.

Bug: 145162678

Test: Unit tests pass.
Test: ./art/test/run-test --dex2oat-jobs 4 --host --prebuild --compact-dex-level fast --jit --no-relocate --runtime-option -Xcheck:jni  137-cfi
Test: ./art/test/testrunner/testrunner.py -t 137 --host
Change-Id: Ic61c4487334fd2273cda9c56eb1a3b525a03edb7
2019-12-03 17:35:00 -08:00
Christopher Ferris 819f13116e Handle when bias is different in elf headers.
The original code assumed that the load bias in the program headers
would be exactly the same as in eh_frame/eh_frame_hdr/debug_frame.

This isn't guaranteed, so add a section bias for use when creating
a DwarfSection. In addtion, make the load bias and section bias
a signed value. There is no reason that this value needs to be positive,
so don't force it to be.

Add a new offline test that has a different load bias in eh_frame than
in the executable load.

Add additional unit tests to verify the load bias values are set properly.

Clean up the tests in ElfInterfaceTest, making all tests names follow the
same convention.

Bug: 141888859
Bug: 142094469

Test: New units and old unit tests pass on host and taimen.
Change-Id: Ib878123ab5545f0f315c749cfe0d27b012d873ee
2019-10-08 17:36:06 +00:00
Christopher Ferris 02a6c448c3 Add support for displaying soname in an apk.
Changes:
- Change GetSoname to always returns a std::string.
- Added new unit tests for the soname printing.
- Modify the GetElf() function to save the same elf when we see rosegment
  linkers that split the read-only and read-write across a map. This
  avoids creating multiple elf objects for each map.
- Fixed a few offline unwind tests.

Bug: 29218999

Test: Unit tests pass.
Change-Id: Iad7c38b5c2957a8c5fd4ba94ebec335bafcad57d
2019-03-13 17:07:46 -07:00
Christopher Ferris bf373edc3c Add caching of build id in MapInfo object.
Change the GetBuildID function to return a std::string.
Added benchmark to check how long it takes to get the build id from
a file versus an elf object.
Added a way to get an elf without passing in a valid process_memory and
added tests for this.

Test: New unit tests.
Change-Id: I3029019767e0181c758d611fe635bc1bf72d6e8e
2019-01-17 20:14:00 -08:00
Florian Mayer da459e56f7 Read .note.gnu.build-id.
This will be used by heapprofd to allow us to correlate build ids with
memory leaks in libraries and binaries.

Test: m
Test: host libunwindstack_test
Test: run unwind_info against my phone's libc.so (32/64) and compare
      to readelf Build ID output.

Bug: 120186412

Change-Id: I3cefd6cce9a8733509bf35b7175eb0f967783477
2018-12-05 14:13:30 +00:00
Christopher Ferris 4cc36d2b43 Fix handling of load bias values.
It turns out that for the dwarf information, if a FDE indicates it's pc
relative, then pc has to be incremented by the load bias. If not, then
it should not be incremented.

Previously, the code always subtracted load bias values from pcs, and assumed
that all fdes were incremented by load bias values. The new code actually
reads the fdes and adjusted the pcs in the fde and in the eh frame hdr so
that load bias values are already handled properly.

In addition, add dumping of arm exidx values in unwind_reg_info. This allowed
verifying that the debug frame in those elf files was being handled properly.

Added a new unit test that only has a debug frame that has a non-zero load
bias and has fde entries that do not have pc relative encoding.

Fix a couple of other small bugs.

Bug: 109824792

Test: All libbacktrace/libunwindstack unit tests pass.
Test: Ran ART 137-cfi test and 004-ThreadStress.
Test: Verify that displaying the fde start and end pc actually match the
Test: real data for fde that have pc relative set, and that don't.
Test: Verified that the unwind information for arm exidx matches the
Test: debug frame data.

Change-Id: I707555286b5cb05df9f25489e8c5ede753cfe0fb
2018-06-11 18:53:55 -07:00
Christopher Ferris 2fcf4cf13e Add error propagation into Unwinder/Elf objects.
The backtrace offline code uses these error codes to diagnose errors.
In addtion, I've had cases where seeing these errors would help diagnose
failures.

This also allows us to add a few features to indicate why an unwind
terminated (such as max frames exceeded).

Bug: 65682279

Test: Updated unit tests pass.
Change-Id: If82b5092698e8a194016d670efff1320f9b44d50
2018-01-24 17:50:46 -08:00
Christopher Ferris 150db124f3 Add ability to read jit gdb data.
Changes:
- New JitDebug class to handle all of the jit gdb interface.
- Add unit tests for all, along with new offline test using debug data.
- Add new Memory type called MemoryOfflineParts that has multiple
  MemoryOffline objects to support the offline test.
- Update the tools to use the JitDebug object.
- Modify libbacktrace to use the JitDebug, but only looking in libart.so
  and libartd.so.
- Change the Format32Bits to Is32Bit since it's more accurate and I use
  it in a different context where original name didn't make sense.
- Add a new function to find global variables in an elf file
  (GetGlobalVariable).
- Add a new function to determine if a pc is valid for this elf (IsValidPc).

Bug: 68396769

Test: Ran new unit tests. Added new offline test that uses jit debug data.
Test: Ran art test that generates jit data and verified a crash unwinds
Test: through the jit data.
Change-Id: I6e7ee2f5bab2242028a06feece156dff21c0a974
2018-01-12 11:18:42 -08:00
Christopher Ferris e7b6624c3f Fix issues in libunwindstack.
- Add a load_bias field in MapInfo so that it can be loaded offline,
  and also so it can be cached.
- Add an Add function to the Maps class so that it's possible to manually
  create a map.
- Remove the OfflineMaps class since I haven't found a reason for this to
  exist.
- Add a pointer to the gnu debugdata compressed section in the interface
  itself and modify the step path to try eh_frame, then debug_frame, then
  gnu_debugdata. This way arm can add exidx as the last step behind
  gnu_debugdata. Add an offline test to verify the order of unwind.
- Fix x86_64_ucontext_t since it was a different size on 32 bit and 64 bit
  systems.

Test: Pass new unit tests.
Change-Id: I978b70d6c244bd307c62a29886d24c1a8cb2af23
2017-12-15 11:17:45 -08:00
Christopher Ferris e69f470933 Multiple bugfixes, small restructuring.
- Move the load bias stored out of ElfInterface into Elf. For the compressed
  sections, the load bias was not the same as the data from the uncompressed
  section.
- Move the initialization of the compressed section into Init. It was too easy
  to forget to call the init of the compressed section.
- Do not automatically add in load bias to the pc before calling ElfInterface
  code. Do all of the pc manipulations in the Elf object.
- Change the interface GetFunctionName code to pass in the load_bias instead
  of modifying the pc inside the code.
- Modify the Step function to pass in the elf offset, not add it to the pc.
  It is necessary to have two different relative values when executing the
  Step: a pc that is relative to the beginning of the elf for the reading data
  the actual instructions when trying to determine if this is in a signal
  frame, and a pc that is relative to the map for finding the appropriate
  unwind information.
- Add a feature to Unwinder so that an unwind can be stopped if it ends up
  in map that has a specified suffix. This is so that the ART unwinding
  code doesn't require skipping the compressed section. Instead, stop at
  if trying to unwind through a known suffix code that means the code is
  in java code. This is important because the compressed section data is
  not only used by the jave compiled code, so that will continue to work.
- Fix tests for restructuring, add new tests for new functionality.

Test: Ran art test 137-cfi using new unwinder as default.
Test: Ran new unit tests.
Change-Id: I42e658c64c5e14f698ba34944a3043afac967884
2017-10-20 11:15:32 -07:00
Christopher Ferris f6f691b63c Update the Unwinder object and add tests.
Changes:
- Remove unused GetReturnAddressFromDefault function and tests.
- Modify the unwinder to stop when a pc/sp in a device map.
- Modify the unwinder to skip initial frames based on map names.
- Unit tests that exercise all of the paths in the unwinder code.
- Move the test Elf/ElfInterface objects into their own file.
- Update RegsFake to handle extra cases.
- Modify libbacktrace code to use this unwinder.

The new unwinder does not implement the ignore frame functionality since
this is not used very often and is better implemented using a skip frames
in named libraries functionality.

Test: Ran new unit tests, ran backtrace tests.
Change-Id: Ifd65e9acd66ac5e2d0e04bd32a9ad870b54610ff
2017-10-04 14:40:14 -07:00