Commit graph

23 commits

Author SHA1 Message Date
Christopher Ferris
4ae266ccbd Add indicator that an elf is memory backed.
Modify the unwinder library to indicate that at least one of the stack
frames contains an elf file that is unreadable.

Modify debuggerd to display a note about the unreadable frame and a possible
way to fix it.

Bug: 129769339

Test: New unit tests pass.
Test: Ran an app that crashes and has an unreadable file and verified the
Test: message is displayed. Then setenforce 0 and verify the message is
Test: not displayed.
Change-Id: Ibc4fe1d117e9b5840290454e90914ddc698d3cc2
2019-04-18 15:37:52 -07:00
Christopher Ferris
d11ed86d65 Fix pc/function name for signal handler frame.
This refactors the step function slightly to split it up into
distinct pieces since the code needs to handle a signal handler
versus normal step slightly differently.

Add a new error for an invalid elf.

Modify libbacktrace code to handle new error code.

Bug: 130302288

Test: libbacktrace/libunwindstack unit tests.
Change-Id: I3fb9b00c02d2cf2cc5911541bba0346c6f39b8e6
2019-04-12 17:23:18 -07:00
David Srbecky
b9cc4fbb26 Revert "Check for data races when reading JIT/DEX entries."
This reverts commit 85b5fecec9.

Reason for revert: Breaks ART tests, reverting to investigate.

Change-Id: I1bb905407e87cbd4f832646651133a9caf6fcfc8
2019-04-05 18:23:32 +00:00
David Srbecky
85b5fecec9 Check for data races when reading JIT/DEX entries.
Update the entries only when the list is modified by the runtime.

Check that the list wasn't concurrently modified when being read.

Bug: 124287208
Test: libunwindstack_test
Test: art/test.py -b --host -r -t 137-cfi
Change-Id: I87ba70322053a01b3d5be1fdf6310e1dc21bb084
2019-03-29 14:01:32 +00:00
Christopher Ferris
7813345faa Add BuildId to frame information.
Update debuggerd to print BuildId information by default.

Bug: 120975492

Test: New unit tests pass.
Test: debuggerd -b <PID> shows build id information.
Test: tombstones include build id information.
Change-Id: I019b031113d0b77385516223c63455b868924440
2019-03-26 08:04:40 -07:00
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
Treehugger Robot
9f5e9978c2 Merge "Allow to move frames out of Unwinder." 2019-01-29 19:23:23 +00:00
Florian Mayer
1c993b76bf Allow to move frames out of Unwinder.
This saves a copy for every unwind we do in heapprofd.

Change-Id: Ife7aa1ce68831729d96ccd4c3e54ca531f98b6bc
2019-01-28 17:11:07 +00:00
Christopher Ferris
4aec66e810 Fix memory leak in UnwinderFromPid object.
Actually make the destructor virtual so that objects in
UnwinderFromPid get freed.

Also, explicitly make the DexFiles and JitDebug destructors virtual.

Bug: 123099840

Test: Ran UnwindTest.local_from_pid thousands of times.
Change-Id: I8bf11c0eb3587fa82f5f14f4723ea5c91da0fd46
2019-01-23 09:49:28 -08:00
Christopher Ferris
eb0772ff4a Add support for UnwinderFromPid object.
This object is able to be easily used from other code and can be used
to replace the libbacktrace calls in other parts of the platform.

Also, demangle the function names when calling FormatFrame.

Bug: 120606663

Test: Unit tests pass, debuggerd using this code directly passes unit
Test: tests.
Change-Id: Ifd8cf9bdd89174c1736810711d20e9f37f29b1bf
2019-01-16 15:13:25 -08:00
Christopher Ferris
a09c4a6ff2 Fix offsets when shared lib split across maps.
The linker was modified so that a shared library has a read-only
map, then a read-execute map to represent the whole shared library.
When backtraces are created, then the offsets are set incorrectly
for backtraces. For example, all backtraces wind up with an offset now,
and a shared library loaded out of an apk shows the wrong offset.

Changes:
- Fix the FormatFrame function which was putting the offset before the
  map name.
- Refactor the Maps and MapInfo classes to keep track of the previous map
  instead of all maps. This was the only map that was ever needed.
- Modify the unwind_for_offline tool to capture both the read-only and
  read-execute map when using the read-only segment option.

Bug: 120981155

Test: Updated unit tests pass.
Test: Unwinds on device don't show the offsets everywhere any more.
Change-Id: I75b3727221be9c20316dfdcd7a1c6d242d7ce948
2018-12-18 11:22:14 -08:00
Christopher Ferris
a2ec50bf57 Change the GetAdjustedRelPc to GetPcAdjustment.
This cleans up a bit of the Unwinder code to make it clear what's
going on.

Modify the offline unit tests to verify the pc and sp to make sure
that those values get computed correctly.

Test: Passes unit tests.
Test: Passes 137-cfi art tests.
Change-Id: I0787a1d77b8726d3defd08f31c7476f6798f8d0d
2018-02-21 20:16:39 -08:00
Christopher Ferris
e4b3a6aaa4 Add ability to skip function name resolution.
Bug: 73558129

Test: New unit tests pass.
Change-Id: I3a6b17d2590aacb367ab3e3a51cc85be73ad64eb
2018-02-20 17:10:23 -08:00
Christopher Ferris
e762f1f193 Check that dex pc is in a valid map.
Add new unit tests for dex pc being non-zero.

Bug: 73004673

Test: Ran unit tests.
Test: Ran art 137-cfi test on host for interpreter.
Change-Id: I09bbf96d0ed65fc1e5896e4ab2bc67867e3b7fdb
2018-02-06 15:00:04 -08:00
Christopher Ferris
d70ea5ea85 Move dex pc frame creation into libunwindstack.
Test: Compiles, all unit tests pass.
Test: Ran 137-cfi art test in interpreter and verified interpreter
Test: frames still show up.

Change-Id: Icea90194986faa733a873e8cf467fc2513eb5573
2018-01-31 14:19:42 -08:00
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
98984b41da Add support for getting a dex pc.
Changes:
- Change the register type from int16_t to uint32_t for the location data
  and the Eval processing. This is because the special dex pc is > 65535.
- Add the ability for Dwarf register location information to point to a
  register that is itself a Dwarf location register.
- Add dex_pc to the frame information.
- Modify the unwind tool to print the dex pc if non-zero.

This does not implement the printing of the dex information in anything
but the unwind tool. It's not the final form of this printing.

Bug: 72070049

Test: Ran new unit tests.
Test: Dumped stack while in interpreter running 137-cfi art test and
Test: verified dex pc is set to non-zero.
Change-Id: I6ce8a6b577fb4f92abacbd433b1f68977e272542
2018-01-17 19:18:00 -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
c3d79f7c07 Fix incorrect usage of relative pcs.
When stepping, it's necessary to use both the unaltered relative pc
and the adjusted relative pc. If the adjusted pc is not used, the
wrong unwind information can be used.

Added new offline unit tests that take real data and verifies that it
unwinds properly.

Fix a bug in the map code that would not properly parse map data for
a 64 bit process when done in a 32 bit process.

Fix bug in eh_frame processing that didn't adjust the pc correctly.
Fix unit tests related to the pc adjustment.

Bug: 69475565

Test: Passes libbacktrace/libunwindstack unit tests.
Test: Run debuggerd -b on processes on a hikey.
Change-Id: Ic501a1c4549c5f61d2742a7105c42a960f2c892b
2017-11-29 16:10:08 -08:00
Christopher Ferris
1cb84cea2f Add an interface for stopping in certain maps.
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
2017-10-24 15:45:59 -07:00
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
Christopher Ferris
b9de87f7ed Add a new unwind method on error.
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
2017-09-22 16:55:12 -07:00