A race condition occurs when one thread takes more than a second to get
scheduled to handle the signal we send to ask it to dump its stack.
When this happens, the main thread will continue on, close the fd, and
then ask the next thread to dump, but the slow thread will then wake up
and try to write to the new thread's fd, or trigger an assertion in
__linker_enable_fallback_allocator.
Do a few things to make this less bad:
- encode both target tid and fd in the shared atomic, so that we know
who each fd is for
- switch __linker_enable_fallback_allocator to return success instead
of aborting, and bail out if it's already in use
- write to the output fd right when we get to it, instead of doing it
whenever the dumping code decides to, to reduce the likelihood that
the timeout expires
Test: debuggerd_test
Change-Id: Ife0f6dae388b601e7f991605f14d7a0274013f6b
Commit 3e235911 in bionic switched LP32's sigaction implementation over
to using the rt_sigaction syscall, matching LP64. Update our seccomp
policy to match.
Bug: http://b/73119572
Test: debuggerd_test32
Change-Id: I0a662a1c874298d434468d2dcdb4ebf9f276110c
Use the art dex file library to read the dex data.
Add unit tests for the UnwindDexFile code.
Bug: 72070049
Test: All unit tests continue to pass.
Test: Dumped the backtrace of the 137-cfi test while running in interpreter
Test: mode and verified that the stack trace is correct. Did this on host
Test: and for arm/arm64.
Change-Id: Ia6f343318c5dd6968a954015a7d59fdf101575b0
The stack dump was not printing leading zeros for data after the
change to remove uintptr_t types from the libbacktrace API.
Bug: 65682279
Test: Created an arm tombstone and an arm64 tombstone and verified
Test: that the stack data has leading zeros.
Change-Id: I1fbec2c4fa7c8b0fab18894c5628d18c5a580299
In order to support the offline unwinding properly, get rid of the
usage of non-fixed type uintptr_t from all API calls.
In addition, completely remove the old local and remote unwinding code
that used libunwind.
The next step will be to move the offline unwinding to the new unwinder.
Bug: 65682279
Test: Ran unit tests for libbacktrace/debuggerd.
Test: Ran debuggerd -b on a few arm and arm64 processes.
Test: Ran crasher and crasher64 and verified tombstones look correct.
Change-Id: Ib0c6cee3ad6785a102b74908a3d8e5e93e5c6b33
Set and restore PR_SET_PTRACER when performing a dump, so that when
Android is running on a kernel that has the Yama LSM enabled (and the
value of ptrace_scope is > 0), crash_dump can attach to processes and
print nice, symbolized stack traces.
Bug: 70992745
Test: kill -6 `pidof surfaceflinger` && logcat -d -b crash
# in both sailfish and Chrome OS
Change-Id: If4646442c6000fdcc69cf4ab95fdc71ae74baaaf
The abort message was accidentally relocated to be printed below the
registers, backtrace, and stack, which isn't very helpful. Move it back
to its rightful place.
Test: treehugger
Change-Id: I8aa5b63e58081f27ccdb42481fed8d9eb3a892a4
When a process crashes, both ActivityManager and init will try to kill
its process group when they notice. The recent change to minimize the
amount of time a process is paused results in crash dumps being killed
before they finish as a result of this. Since anything that needs to be
low-latency is probably not going to be too happy if it crashes, just
wait for completion whenever we're processing a real crash.
Bug: http://b/70343110
Test: debuggerd_test
Change-Id: I894bb06efd264b1ba005df06f7326a72f4b767bb
Add some helper macros that perform regex string matching to
<android-base/test_utils.h>.
Test: libbase_test32/64 on host
Change-Id: I1b0f03dc73f8b4fdfb8ac6c75d59ef421e0e9640
Add a benchmark to measure how long we pause a process when dumping.
Bug: http://b/62112103
Test: manually ran it
Change-Id: Iceec2f722915b0ae26144c86dcbeb35793f963da
Reduce the amount of time that a process remains paused by pausing its
threads, fetching their registers, and then performing unwinding on a
copy of its address space. This also works around a kernel change
that's in 4.9 that prevents ptrace from reading memory of processes
that we don't have immediate permissions to ptrace (even if we
previously ptraced them).
Bug: http://b/62112103
Bug: http://b/63989615
Test: treehugger
Change-Id: I7b9cc5dd8f54a354bc61f1bda0d2b7a8a55733c4
Add a static GetLoadBias method to the Elf object that only reads just
enough to get the load bias.
Add a method to MapInfo that gets the load bias. First attempt to get
it if the elf object already exists. If no elf object was created, use
the new static method to get the load bias.
In BacktraceMap, add a custom iterator so that when code dereferences
a map element, that's when the load bias will be retrieved if it hasn't
already been set.
Bug: 69871050
Test: New unit tests, verify tombstones have non-zero load bias values for
Test: libraries with a non-zero load bias.
Change-Id: I125f4abc827589957fce2f0df24b0f25d037d732
Always check to see if the fallback handler has been called and is
not trying to dump a specific thread.
Bug: 69110957
Test: Verified on a system where the prctl value changes, that before the
Test: change it dumps multiple tombstones, and after the change it
Test: works as expected.
Test: Ran debuggerd unit tests.
Test: Dumped process using debuggerd -b <PID> and debuggerd <PID>.
Change-Id: Id98bbe96cced9335f7c3e17088bb4ab2ad2e7a64
Nobody is looking at the mismatches, and it can cause problems
with tombstone parsers.
Also, fix the dump_header_info test and remove unused properties_fake.cpp.
Test: Ran unit tests, verified tombstones still work.
Change-Id: I4261646016b4e84b26a5aee72f3227f1ce48ec9a
This is needed if they will ever handle ro. properties that have
values longer than 92 characters.
Bug: 23102347
Bug: 34954705
Test: read and write properties with value length > 92 characters
Change-Id: I44aa135c97ec010f12162c30f743387810ae2c5d
Update the tests to match new output (and stop pluralizing '1 entries').
Test: `debuggerd_test{32,64} --gtest_filter="TombstoneTest.*" on hikey960
Change-Id: I16b0335715303252fad3a35d6a053a50fefdac30
Tombstones (especially ones with lots of VMAs) are regularly truncated.
We can at least show the number of VMAs, though, for anyone interested
in knowing whether they got close to the default 64Ki limit.
Bug: http://b/66911122
Test: ran crasher, examined tombstone
Change-Id: I286db66f28f132307d573dbe5164efc969dc6ddc
Apply the same fix from c2e98f63 to intercept_manager.cpp.
Bug: http://b/64543673
Test: debuggerd_test
Change-Id: Ibfb919e059fa62f8336cfc1426d03ef015590136
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
Android.bp assumed only an armv7-a-neon core needs to set HAS_VFP_D32.
In fact, an armv8 core also has 32 double-word floating point registers
for A32 and T32 ISAs (AArch32 or 32-bit armv8).
Bug: 65568426
Test: lunch aosp_arm64; emulator # on oc-mr1-dev; boot to home screen.
Check crashglue.o actually uses VFP_D16-31 for 32-bit armv8 core.
Change-Id: I34584a27fa24a55bb4809ccd7f99a8122971df0e
The order of arguments is wrong - we're passing flags=static_cast<unsigned>(-1)
and backlog=LEV_OPT_CLOSE_ON_FREE (which is 2).
On versions of libevent prior to 2.1.8, this ends up accidentally setting
OPT_LEAVE_SOCKETS_BLOCKING, OPT_CLOSE_ON_EXEC, OPT_REUSABLE and OPT_THREADSAFE
and limiting our backlog to two. These unintentional changes are relatively
benign; we never make our sockets block, we never exec, we never reuse
sockets and the additional locking overhead should be negligible. The
backlog of two might be a problem in theory, but there haven't been any
reports of issues caused by it.
Things get worse on 2.1.8 - that version introduces several new flags,
one of which is OPT_DISABLED. This disables the new listener by default,
which means that our event loop returns early because it has no active listeners
for any of its events.
Bug: 64543673
Test: Manual.
Change-Id: I9954bc7fe1af761de1a950d935dd2e6ce7e2c5f5
Move libdebuggerd headers into their own directory for namespacing,
move some includes to the top of their implementing files, delete some
dead code.
Test: mma, treehugger
Change-Id: Ie4c44e32e2ab3bc678092899d257fd4ed634aa34
Instead of printing a useless "ptrace attach failed: strerror(EPERM)"
message, print the name and pid of a competing tracer when we fail to
attach because a process is already being ptraced.
Bug: http://b/31531918
Test: debuggerd_test32, debuggerd_test64 on aosp_angler
Test: strace -p `pidof surfaceflinger`; debuggerd -b surfaceflinger
Change-Id: Ifd3f80fe03de30ff38c0e0068560a7b12875f29d
