Skip to content

Fix AsyncLocalCompat to work the same on dotnet core#27

Closed
bcuff wants to merge 1 commit intoDataDog:masterfrom
scopely:async-local-fix
Closed

Fix AsyncLocalCompat to work the same on dotnet core#27
bcuff wants to merge 1 commit intoDataDog:masterfrom
scopely:async-local-fix

Conversation

@bcuff
Copy link
Copy Markdown

@bcuff bcuff commented Dec 19, 2017

No description provided.

@palazzem palazzem added this to the 0.1.2 milestone Jan 15, 2018
@palazzem palazzem added the area:tracer The core tracer library (Datadog.Trace, does not include OpenTracing, native code, or integrations) label Jan 15, 2018
@palazzem palazzem requested a review from bmermet January 15, 2018 23:20
@palazzem palazzem removed this from the 0.1.2 milestone Jan 19, 2018
@bmermet
Copy link
Copy Markdown
Contributor

bmermet commented Jan 22, 2018

Hi @bcuff,

I apologize for taking so much time to get back to you. Good catch here, indeed the two implementations don't behave identically but i'd rather fix it the other way around and make the .net framework implementation behave like the .net core one. This class is meant to be instantiated only once and that way it makes sure that two instances of the class do not have side effect on one another.

To achieve that I think we could simply remove the name parameter from the constructor and instead generate a random id and use it to perform LogicalSetData and LogicalGetData.

What do you think?

@bcuff
Copy link
Copy Markdown
Author

bcuff commented Jan 22, 2018

sure that works. I'll close this.

@bcuff bcuff closed this Jan 22, 2018
@bcuff bcuff deleted the async-local-fix branch January 22, 2018 16:06
@bmermet
Copy link
Copy Markdown
Contributor

bmermet commented Feb 1, 2018

#37 addresses this issue

@bcuff
Copy link
Copy Markdown
Author

bcuff commented Feb 1, 2018

👍

andrewlock pushed a commit that referenced this pull request Jul 26, 2024
…5808)

## Summary of changes

Prevent deadlock betwen signal-based profilers (walltime/manual cpu
profilers) and non-signal based profilers (exception, contention....)

## Reason for change

When an exception occurs, the thread can be interrupted by a
signal-based profiler (walltime/manual cpu). It can be interrupted while
holding the lock used to update the `dl-iterate-phdr` cache.

```
Thread 18 (LWP 995):
#0  __syscall_cp_c (nr=202, u=140244538814536, v=128, w=-1, x=0, y=0, z=0) at ./arch/x86_64/syscall_arch.h:61
#1  0x00007f8dba343ccd in __futex4_cp (to=0x0, val=-1, op=128, addr=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at src/thread/__timedwait.c:24
#2  __timedwait_cp (addr=addr@entry=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>, val=val@entry=-1, clk=clk@entry=0, at=at@entry=0x0, priv=priv@entry=128) at src/thread/__timedwait.c:52
#3  0x00007f8dba343d74 in __timedwait (addr=addr@entry=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>, val=-1, clk=clk@entry=0, at=at@entry=0x0, priv=128) at src/thread/__timedwait.c:68
#4  0x00007f8dba3463e6 in __pthread_rwlock_timedrdlock (at=<optimized out>, rw=<optimized out>) at src/thread/pthread_rwlock_timedrdlock.c:18
#5  __pthread_rwlock_timedrdlock (rw=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>, at=0x0) at src/thread/pthread_rwlock_timedrdlock.c:3
#6  0x00007f8d398f3ca8 in std::__glibcxx_rwlock_rdlock (__rwlock=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/shared_mutex:73
#7  std::__shared_mutex_pthread::lock_shared (this=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/shared_mutex:224
#8  std::shared_mutex::lock_shared (this=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/shared_mutex:421
#9  std::shared_lock<std::shared_mutex>::shared_lock (this=0x7f4ca05a2ac0, __m=...) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/shared_mutex:722
#10 LibrariesInfoCache::DlIteratePhdrImpl (this=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>, callback=0x7f8d3997d900 <_Ux86_64_dwarf_callback>, data=0x7f4ca05a2b20) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/LibrariesInfoCache.cpp:104
#11 0x00007f8d3997e4ee in _Ux86_64_dwarf_find_proc_info (as=0x7f8d39eb2a00 <local_addr_space>, ip=140246691112115, pi=0x7f4ca05a3170, need_unwind_info=1, arg=0x7f4ca05a3411) at /project/obj/libunwind-prefix/src/libunwind/src/dwarf/Gfind_proc_info-lsb.c:807
#12 0x00007f8d3997e690 in fetch_proc_info (c=0x7f4ca05a3018, ip=140246691112115) at /project/obj/libunwind-prefix/src/libunwind/src/dwarf/Gparser.c:473
#13 0x00007f8d3998113d in find_reg_state (sr=0x7f4ca05a2dc0, c=0x7f4ca05a3018) at /project/obj/libunwind-prefix/src/libunwind/src/dwarf/Gparser.c:1024
#14 _Ux86_64_dwarf_step (c=c@entry=0x7f4ca05a3018) at /project/obj/libunwind-prefix/src/libunwind/src/dwarf/Gparser.c:1069
#15 0x00007f8d3997d13a in _Ux86_64_step (cursor=0x7f4ca05a3018) at /project/obj/libunwind-prefix/src/libunwind/src/x86_64/Gstep.c:75
#16 0x00007f8d398f55c8 in LinuxStackFramesCollector::CollectStackManually (this=this@entry=0x7f8d392dc6d0, ctx=ctx@entry=0x7f4ca05a3880) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/LinuxStackFramesCollector.cpp:288
#17 0x00007f8d398f53dc in LinuxStackFramesCollector::CollectCallStackCurrentThread (this=this@entry=0x7f8d392dc6d0, ctx=ctx@entry=0x7f4ca05a3880) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/LinuxStackFramesCollector.cpp:227
#18 0x00007f8d398f4672 in LinuxStackFramesCollector::CollectStackSampleSignalHandler (signal=<optimized out>, info=<optimized out>, context=0x7f4ca05a3880) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/LinuxStackFramesCollector.cpp:373
#19 0x00007f8d398fb871 in ProfilerSignalManager::CallCustomHandler (this=0x7f8d39eaf928 <ProfilerSignalManager::Get(int)::signalManagers+1944>, signal=10, info=0x7f4ca05a39b0, context=0x7f4ca05a3880) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/ProfilerSignalManager.cpp:197
#20 ProfilerSignalManager::SignalHandler (signal=10, info=0x7f4ca05a39b0, context=0x7f4ca05a3880) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/ProfilerSignalManager.cpp:188
#21 <signal handler called>
#22 __pthread_rwlock_unlock (rw=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at src/thread/pthread_rwlock_unlock.c:5
#23 0x00007f8d398f3bf9 in std::__glibcxx_rwlock_unlock (__rwlock=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/shared_mutex:77
#24 std::__shared_mutex_pthread::unlock (this=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/shared_mutex:208
#25 std::shared_mutex::unlock (this=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/shared_mutex:417
#26 std::unique_lock<std::shared_mutex>::unlock (this=0x7f4ca05a3e20) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/bits/unique_lock.h:194
#27 std::unique_lock<std::shared_mutex>::~unique_lock (this=0x7f4ca05a3e20) at /usr/lib/gcc/x86_64-alpine-linux-musl/10.3.1/../../../../include/c++/10.3.1/bits/unique_lock.h:103
#28 LibrariesInfoCache::UpdateCache (this=0x7f8d39eaf048 <LibrariesInfoCache::Get()::Instance>) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/LibrariesInfoCache.cpp:88
#29 0x00007f8d398f4e59 in LinuxStackFramesCollector::CollectStackSampleImplementation (this=0x7f8d3b91bc90, pThreadInfo=0x7f4ca06b9900, pHR=0x7f8d3a63c510, selfCollect=true) at /p--Type <RET> for more, q to quit, c to continue without paging--
roject/profiler/src/ProfilerEngine/Datadog.Profiler.Native.Linux/LinuxStackFramesCollector.cpp:100
#30 0x00007f8d399637ba in StackFramesCollectorBase::CollectStackSample (this=0x7f8d3b91bc90, pThreadInfo=0x7f4ca06b9900, pHR=0x7f4ca05a3fdc) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native/StackFramesCollectorBase.cpp:185
#31 0x00007f8d3992acb9 in ExceptionsProvider::OnExceptionThrown (this=0x7f8d392a7160, thrownObjectId=139969739182080) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native/ExceptionsProvider.cpp:149
#32 0x00007f8d39917045 in CorProfilerCallback::ExceptionThrown (this=0x7f8d392c0d20, thrownObjectId=139969739182080) at /project/profiler/src/ProfilerEngine/Datadog.Profiler.Native/CorProfilerCallback.cpp:1734
```
## Implementation details

- move the call which updates the cache after acquiring the thread lock
- call Update before sending signal

## Test coverage

## Other details
<!-- Fixes #{issue} -->

<!-- ⚠️ Note: where possible, please obtain 2 approvals prior to
merging. Unless CODEOWNERS specifies otherwise, for external teams it is
typically best to have one review from a team member, and one review
from apm-dotnet. Trivial changes do not require 2 reviews. -->
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

area:tracer The core tracer library (Datadog.Trace, does not include OpenTracing, native code, or integrations)

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants