The key difference that --enable-cxx-exceptions makes is that it results in libunwind having _Unwind_RaiseException (and likely other functions), which gets called during a C++ throw by __cxa_throw. Without libunwind, this symbol is provided by libgcc_s, whose implementation works correctly. For whatever reason, the one in libunwind, on aarch64, does not succeed in finding a handler and instead calls terminate (which is normal when there is no handler for an exception).
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to libunwind in Ubuntu. https://bugs.launchpad.net/bugs/1999104 Title: libunwind causes crashes on arm64 Status in libunwind package in Ubuntu: New Bug description: There is a bug in libunwind in both 18.04 and 20.04 on arm64 where when linked with libunwind instead of catching an exception, the program crashes. This was first seen on mcrouter, but attached is a small reproducer where `main_unwind` will crash. The libunwind shipping with 22.04 doesn't appear to have this problem, nor do unmodified upstream versions (including the 1.2.1 which is the 18.04 and 20.04 version). Attached is a small reproducer that demonstrates the problem. Ubuntu 22.04: ``` $ ./main int throws lib int caught main $ ./main_unwind int throws lib int caught main ``` Ubuntu 20.04: ``` $ ./main int throws lib int caught main $ ./main_unwind terminate called after throwing an instance of 'int' terminate called recursively Aborted (core dumped) ``` To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libunwind/+bug/1999104/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
