Please backport fix for bugs.debian.org/827015
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
libunwind (Debian) |
Fix Released
|
Unknown
|
|||
libunwind (Ubuntu) |
Fix Released
|
Medium
|
Unassigned | ||
Trusty |
Triaged
|
Medium
|
Unassigned | ||
Xenial |
Triaged
|
Medium
|
Unassigned |
Bug Description
[Impact]
When a C++ exception is thrown with libunwind linked in, the signal mask is corrupted.
For MongoDB, if the CPU profiler is enabled (which requires linking libunwind), any exception that is raised within the server may cause random signals to become unblocked on a thread. If SIGTERM becomes unblocked on any thread but the main thread, the server won't exit cleanly (this is particularly evident when running the MongoDB test suite, which starts/stops servers repeatedly).
This also seems to impact Pyston: https:/
[Test Case]
I've attached the test case from the upstream Debian bug (https:/
$ g++ sigtest.cpp -lpthread
$ ./a.out
Signals blocked: 1 (Hangup) 65 (Unknown signal 65)
Throw exception
Signals blocked: 1 (Hangup) 65 (Unknown signal 65)
$ g++ sigtest.cpp -lpthread -lunwind
$ ./a.out
Signals blocked: 1 (Hangup) 65 (Unknown signal 65)
Throw exception
Signals blocked: 7 (Bus error) 8 (Floating point exception) 10 (User defined signal 1) 12 (User defined signal 2) 13 (Broken pipe) 15 (Terminated) 17 (Child exited) 20 (Stopped)21 (Stopped (tty input)) 25 (File size limit exceeded) 26 (Virtual timer expired) 27 (Profiling timer expired) 28 (Window changed) 29 (I/O possible) 30 (Power failure) 31 (Bad system call) 32 (Unknown signal 32) 33 (Unknown signal 33) 34 (Real-time signal 0) 35 (Real-time signal 1) 36 (Real-time signal 2) 37 (Real-time signal 3) 38 (Real-time signal 4) 39 (Real-time signal 5) 40 (Real-time signal 6) 41 (Real-time signal 7) 42 (Real-time signal 8) 43 (Real-time signal 9) 44 (Real-time signal 10) 45 (Real-time signal 11) 46 (Real-time signal 12) 47 (Real-time signal 13) 65 (Unknown signal 65)
[Regression Potential]
This fix is already present in bionic and Debian testing, and has been for a couple months. The upstream fix has existed for over a year.
description: | updated |
Changed in libunwind (Debian): | |
status: | Unknown → Fix Released |
description: | updated |
Changed in libunwind (Ubuntu): | |
status: | New → Triaged |
importance: | Undecided → Medium |
status: | Triaged → Fix Released |
Changed in libunwind (Ubuntu Xenial): | |
status: | New → Triaged |
Changed in libunwind (Ubuntu Trusty): | |
importance: | Undecided → Medium |
Changed in libunwind (Ubuntu Xenial): | |
importance: | Undecided → Medium |
Changed in libunwind (Ubuntu Trusty): | |
status: | New → Triaged |
Thanks for taking your time to report this issue and help making Ubuntu better.
Could you take a look at the steps for Stable Release Updates ( https:/ /wiki.ubuntu. com/StableRelea seUpdates# Procedure) and update the description? :)