The process_vm_read function is much faster than ptrace, but sometimes
that will not work on a remote process. Modify the libunwindstack
MemoryRemote object to figure out which one it can use.
Wrote new unit test to verify this checking behavior.
Modify libbacktrace so that the read from libunwind is used instead of
using the default ptrace calls.
Add some benchmarks to libbacktrace to compare the two different methods.
Test: Ran unit tests libbacktrace/libunwindstack/debuggerd.
Test: Ran debuggerd -b <SYSTEM_SERVER_PID>
Test: Ran debuggerd -b <MEDIACODEC PID>
Test: Ran debuggerd -b <RANDOM_PID>
Test: Used crasher to create tombstones and verified stack data is
Test: dumped properly.
Change-Id: If75ca238289532dd8e1de430d569cabb2523380a
Add an ArchEnum to express the arch of the Elf objects and Reg objects.
Split out the regs code into per arch pieces and generic parts.
Also, split out the header files for each arch.
Do not break out the test code yet, there isn't enough and it doesn't
help to maintain the tests.
Test: libunwindstack/libbacktrace/debuggerd unit tests pass.
Test: Running debuggerd -b <PIDS> yields valid data on bullhead.
Change-Id: If61f6c730c9ff2249f986b41de8c4d62f7158325
When doing a remote unwind, and there is a crash in the unwind stack
code or in libbacktrace, the old version would skip those frames.
This makes debugging crashes in those libraries a bit difficult.
Bug: 68820611
Test: Ran unit tests.
Test: kill -3 a zygote process and verify no frames in
Test: libunwindstack.so/libbacktrace.so.
Test: Forced a crash in libunwindstack.so and verified the tombstone
Test: contains the full crash.
Change-Id: I297e5b3775c87c0dddf57ebb423bd72ba1baf193
If libbacktrace is statically linked into a library that interposes
libc, exit-time destructors can lead to a segfault upon exit if static
variables are used after their destruction.
Remove the one use of a static variable (with inconsequential
performance impact of less than 1us per backtrace), and enable
-Wexit-time-destructors to ensure this stays fixed in the future.
Test: mma
Change-Id: Icdaf1cf1c1f166cf501d9ecd1983c44e4305f7e9
Correct for the number of skipped frames when unwinding with
libunwindstack.
Test: backtrace_test32 --gtest_filter="unwind_frame_skip_*"
Change-Id: I9528977104fde3c4ec792a6db1ada24ed571b867
Also, change the std::set parameters to std::vector. As jmgao points out,
a small std::set is not really the best choice for performance reasons.
Test: All unit tests pass, enabled the new unwinder and did a kill -3 on
Test: an android process.
Change-Id: I81227d7b79a9b7cf1d54fb0e3331d3cf4d4d3c4f
Also move the Backtrace::CreateNew function into the same place as ::Create
in preparation for the switch to the new unwinder as the base.
Test: Verify that names are demangled properly.
Change-Id: I6274cd43ea52210523e1e1ce23af5b22f62f4573
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
If a function crashes by jumping into unexecutable code, the old method
could not unwind through that. Add a fallback method to set the pc from
the default return address location.
In addition, add a new finished check for steps. This will provide a method
to indicate that this step is the last step. This prevents cases where
the fallback method might be triggered incorrectly.
Update the libbacktrace code to unwind using the new methodology.
Update the unwind tool to use the new unwind methodology.
Add a new option to crasher that calls through a null function.
Create a new object, Unwinder, that encapsulates the a basic unwind. For now,
libbacktrace will still use the custom code.
Added new unit tests to cover the new cases. Also add a test that
crashes calling a nullptr as a function, and then has call frames in
the signal stack.
Bug: 65842173
Test: Pass all unit tests, verify crasher dumps properly.
Change-Id: Ia18430ab107e9f7bdf0e14a9b74710b1280bd7f4
New function to create the process memory object. This allows for
a future where different remote process memory objects could be created
depending on the way remote memory can be created. Even different local
memory objects that access memory without doing any checks.
It also allows MemoryRange objects to share one single process memory object
and could help if the process memory object caches data.
Small changes to MapInfo::CreateMemory to when some errors are detected.
- Always check if the map is a device map, instead of only if the name
is not empty.
- Check if a memory map is readable before creating the memory from process
memory.
Bug: 23762183
Test: Ran unit tests, unwound on device using the new code.
Change-Id: I12a93c2dc19639689a528ec41c67bfac74d431b3
There are no actual users of the machine type output parameter to
Regs::RemoteGet. The concrete implementations of Regs know what machine
type they represent anyway, so provide an accessor to query.
Test: treehugger
Test: libunwindstack tests on 32/64-bit host, hikey960
Change-Id: Ia25910531d36c41b2b6919f154cfa914aae63117
Also add a comment to the GetElf function to indicate that it never returns
nullptr.
Also needed to add this library to the a million and one places that the vndk
has hard-coded this data.
Bug: 23762183
Test: Built, nothing uses the new code.
Test: However, I did run backtrace_test using this code, and all tests pass.
Change-Id: Ib270665dcb7a7607075e36d88be76dbde6e2faa8
(cherry picked from commit dc4104b720)
Also add a comment to the GetElf function to indicate that it never returns
nullptr.
Bug: 23762183
Test: Built, nothing uses the new code.
Test: However, I did run backtrace_test using this code, and all tests pass.
Change-Id: I252b9c2497e2d3d94347dd6e506170bf50cbfe16
Christopher Ferris