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by zX41ZdbW 1087 days ago
The best way I've found is - patching LLVM's libunwind to make it fully async-signal safe, and sending the stack trace to another thread for symbolization. This is implemented in ClickHouse.
1 comments
einpoklum 1087 days ago
1. Can you link to that?

2. Have these changes been offered as patch for libunwind or boost::stacktrace?

link
zX41ZdbW 1087 days ago
https://github.com/ClickHouse/libunwind/

There were multiple steps:

1. Avoid using malloc/free inside libunwind.

2. Avoid using FDECache that required a mutex.

3. Avoid using dl_iterate_phdr (a mutex inside libc).

4. Protection from dereferencing wrong pointers due to incorrect unwind tables.

Most of the changes were integrated to libunwind, but not everything. Example: https://bugs.llvm.org/show_bug.cgi?id=48186

link