Normally, platform-specific note types in the toolchain are prefixed
with the platform name. Because we're exposing the NT_TYPE_MEMTAG and
synthesizing the note in the toolchain in an upcoming patch
(https://reviews.llvm.org/D118948), it's been requested that we change
the name to include the platform prefix.
While NT_TYPE_IDENT and NT_TYPE_KUSER aren't known about or synthesized
by the toolchain, update those references as well for consistency.
Bug: N/A
Test: Build Android
Change-Id: I7742e4917ae275d59d7984991664ea48028053a1
For a 32-bit userspace, `struct LinkedListEntry` takes 8 bytes for
storing the two pointers, a default block allocator size alignment of
16-bytes would waste 50% of memory. By changing the alignment to size
of a pointer, it saves >1MB memory postboot on wembley device.
Bug: http://b/206889551
Test: bionic-unit-tests
Change-Id: Ie92399c9bb3971f631396ee09bbbfd7eb17dc1a7
Bug: http://b/197147102
Bug: http://b/214080353
With https://reviews.llvm.org/D77491, clang got stricter when issuing
diagnostics regarding builtin functions.
https://reviews.llvm.org/D112024 adds a diagnose_as_builtin attribute
which lets it diagnose builtins even though their signature is slightly
different. This patch adds diagnose_as_builtin attribute as needed.
Versioner is built with an older clang so it doesn't recognize this
attribute. So this is added with a preprocessor check on clang
versions. We can remove the version check once versioner gets updated
shortly after the compiler update.
Test: mmma bionic/tests with clang-r445002
Change-Id: I3d0d63ecdbea0cffe97eb5110e2d9f2a7595a38e
This change is to allocate `head_` and `tail_` outside of LinkedList
and only keep a readonly pointer there. By doing this, all updates
of the list touches memory other than the LinkedList itself, thus
preventing copy-on-write pages being allocated in child processes
when the list changes.
The other approach is to make the LinkedList a singly-linked list,
however, that approach would cause a full list traversal to add
one item to the list. And preliminary number shows there are ~60K
calls to `soinfo::add_secondary_namespace` during Android bootup
on a wembley device, where a singly-linked approach could be
hurting performance.
NOTE: the header is allocated and initialized upon first use instead
of being allocated in the constructor, the latter ends up in crash.
This is likely caused by static initialization order in the linker,
e.g. g_soinfo_list_allocator is a static object, and if this linked
list is embedded into some other static objects, there's no guarantee
the allocator will be available.
Bug: http://b/206889551
Test: bionic-unit-tests
Change-Id: Ic6f053881f85f9dc5d249bb7d7443d7a9a7f214f
Bug: http://b/214080353
The wrong alignment to aligned_alloc() is deliberate. Silence the
warning around the test.
Test: build with clang-r445002
Change-Id: I73bad7775423c908c2bbe1c550e8ce5aeede129d
The first time should_trace() returns true, bionic_trace_begin() calls
open() on trace_marker.
The problem is that open() can call bionic_trace_begin(). We've observed
this happening, for example when:
* fdtrack is enabled. dlopen("libfdtrack.so") can be used to enable
fdtrack on a process.
* ThreadA is busy unwinding inside fdtrack and is holding an fdtrack
internal mutex.
* ThreadB calls bionic_trace_begin() for the first time since the
property "debug.atrace.tags.enableflags" contains ATRACE_TAG_BIONIC.
* ThreadB calls open("/sys/kernel/tracing/trace_marker"). Since fdtrack
is enabled, ThreadB tries to do unwinding as well.
* ThreadB, inside fdtrack's unwinding tries to grab the same mutex that
ThreadA is holding.
* Mutex contention is reported using bionic_systrace, therefore
bionic_trace_begin() is called again on ThreadB.
* ThreadB tries to grab g_lock in bionin_systrace.cpp, but that's
already held by ThreadB itself, earlier on the stack. Therefore
ThreadB is stuck.
I managed to reproduce the above scenario by manually pausing ThreadA
inside unwinding with a debugger and letting ThreadB hitting
bionic_trace_begin() for the first time.
We could avoid using g_lock while calling open() (either by releasing
g_lock and reacquiring it later, or by using atomics), but
bionic_trace_begin() would try to call open() again. In my tests, open()
does not call bionic_trace_begin() a third time, because fdtrack has
reentrancy protection, but there might be another code path inside open
that calls bionic_trace_begin again (it could be racy or only happen in
certain configurations).
This commit fixes the problem by implementing reentrancy protection in
bionic_systrace.
Sample callstack from ThreadA deadlocked before the fix:
```
* frame #0: 0x0000007436db077c libc.so`syscall at syscall.S:41
frame #1: 0x0000007436db0ba0 libc.so`bionic_trace_begin(char const*) [inlined] __futex(ftx=0x000000743737a548, op=<unavailable>, value=2, timeout=0x0000000000000000, bitset=-1) at bionic_futex.h:45:16
frame #2: 0x0000007436db0b8c libc.so`bionic_trace_begin(char const*) [inlined] __futex_wait_ex(ftx=0x000000743737a548, value=2) at bionic_futex.h:66:10
frame #3: 0x0000007436db0b78 libc.so`bionic_trace_begin(char const*) [inlined] Lock::lock(this=0x000000743737a548) at bionic_lock.h:67:7
frame #4: 0x0000007436db0b74 libc.so`bionic_trace_begin(char const*) [inlined] should_trace() at bionic_systrace.cpp:38:10
frame #5: 0x0000007436db0b74 libc.so`bionic_trace_begin(message="Contending for pthread mutex") at bionic_systrace.cpp:59:8
frame #6: 0x0000007436e193e4 libc.so`NonPI::MutexLockWithTimeout(pthread_mutex_internal_t*, bool, timespec const*) [inlined] NonPI::NormalMutexLock(mutex=0x0000007296cae9f0, shared=0, use_realtime_clock=false, abs_timeout_or_null=0x0000000000000000) at pthread_mutex.cpp:592:17
frame #7: 0x0000007436e193c8 libc.so`NonPI::MutexLockWithTimeout(mutex=0x0000007296cae9f0, use_realtime_clock=false, abs_timeout_or_null=0x0000000000000000) at pthread_mutex.cpp:719:16
frame #8: 0x0000007436e1912c libc.so`::pthread_mutex_lock(mutex_interface=<unavailable>) at pthread_mutex.cpp:839:12 [artificial]
frame #9: 0x00000071a4e5b290 libfdtrack.so`std::__1::mutex::lock() [inlined] std::__1::__libcpp_mutex_lock(__m=<unavailable>) at __threading_support:256:10
frame #10: 0x00000071a4e5b28c libfdtrack.so`std::__1::mutex::lock(this=<unavailable>) at mutex.cpp:31:14
frame #11: 0x00000071a4e32634 libfdtrack.so`unwindstack::Elf::Step(unsigned long, unwindstack::Regs*, unwindstack::Memory*, bool*, bool*) [inlined] std::__1::lock_guard<std::__1::mutex>::lock_guard(__m=0x0000007296cae9f0) at __mutex_base:104:27
frame #12: 0x00000071a4e32618 libfdtrack.so`unwindstack::Elf::Step(this=0x0000007296cae9c0, rel_pc=66116, regs=0x0000007266ca0470, process_memory=0x0000007246caa130, finished=0x0000007ff910efb4, is_signal_frame=0x0000007ff910efb0) at Elf.cpp:206:31
frame #13: 0x00000071a4e2b3b0 libfdtrack.so`unwindstack::LocalUnwinder::Unwind(this=0x00000071a4ea1528, frame_info=<unavailable>, max_frames=34) at LocalUnwinder.cpp:102:22
frame #14: 0x00000071a4e2a3ec libfdtrack.so`fd_hook(event=<unavailable>) at fdtrack.cpp:119:18
frame #15: 0x0000007436dbf684 libc.so`::__open_2(pathname=<unavailable>, flags=<unavailable>) at open.cpp:72:10
frame #16: 0x0000007436db0a04 libc.so`bionic_trace_begin(char const*) [inlined] open(pathname=<unavailable>, flags=524289) at fcntl.h:63:12
frame #17: 0x0000007436db09f0 libc.so`bionic_trace_begin(char const*) [inlined] get_trace_marker_fd() at bionic_systrace.cpp:49:25
frame #18: 0x0000007436db09c0 libc.so`bionic_trace_begin(message="pthread_create") at bionic_systrace.cpp:63:25
```
Bug: 213642769
Change-Id: I10d331859045cb4a8609b007f5c6cf2577ff44df
Update the path to the helper binary, and run the test on non-MTE
hardware with the expectation that the bug is not detected.
Test: bionic-unit-tests
Bug: none
Change-Id: I34eb4dc46d0bacd83824d307398f7891d4806686
Unfortunately we have discovered that some applications in the wild
are using PAC instructions incorrectly. To keep those applications
working on PAC enabled devices, disable PAC in application processes
for now.
Bug: 212660282
Change-Id: I3030c47be9d02a27505bd4775c1982a20755758c
This was probably the least worst choice at the time, but we have toybox
readelf now, which is a much lighter-weight dependency (that we already
have for some other tests).
This is also one less use of the *renderscript* LLVM, which we'll be
wanting to finally delete soon.
Test: treehugger
Change-Id: I0e05b8f139ec6e6a425b575368f3d514b8b1cc64
There's potential here to maybe lose some/all of builtins.cpp, but I'll
look at that separately later.
Test: treehugger
Change-Id: I2c2bc1d0753affdd214daeb09fa1ac7cd73db347
It's not clear this was ever needed, it doesn't seem to make any
difference now, and these are the defaults for the obsolete renderscript
LLVM anyway, so... yeah.
This was noticed because it was causing some of our tests to be built as
C++11 rather than [the current default of] C++17.
Test: treehugger
Change-Id: I7d72b3fd58e9cf9a02048b0298eee845d19307f7
