[llvm-dev] some questions on libunwind

[Joerg Sonnenberger via llvm-dev]

On Mon, Dec 20, 2021 at 06:53:34PM +0800, PoYao Chang via llvm-dev wrote:
> > 2. nongnu implementation exposes a specialized unw_init_local2 for stack
> > capturing initiated at signal frame, but this function is not provided at
> > LLVM's world. According to the test cases in LLVM's repo, I inferred that
> > LLVM does not need user to specify the signal frame argument. Is this true?

The assumption is that the kernel/libc correctly registers or provides
CFI annotation for the signal frame and that it is therefore
unnecessary.

> > 3. Is there any previous discussion in LLVM side on the deadlock situation
> > of jemalloc and libunwind?

Make sure that jemalloc locks are unlocked before printing a stack
frame. There really isn't much libunwind can do at this point given that
DSOs can be concurrently loaded or unloaded all the time.

Joerg