Re: [PATCH 0/8] unwind, arm64: add sframe unwinder for kernel

Song Liu <[email protected]> Thu, 13 Feb 2025 12:46:08 -0800

Newsgroups	org.kernel.vger.linux-toolchains,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-kernel,org.kernel.vger.live-patching
Message-ID	<CAPhsuW7bo4efVYb8uPkQ1v9TE95_CQ6+G3q4kVyt-8g-3JD6Cw@mail.gmail.com>

On Thu, Feb 13, 2025 at 12:38 AM Puranjay Mohan <[email protected]> wrote:
[...]
>
> P.S. - The livepatch doesn't have copy_process() but only copy_signal(),
> yours had copy_process() somehow.

In my build, copy_signal is inlined to copy_process, unless I add noinline.
If I do add noinline, the issue will not reproduce.

I tried more combinations. The issue doesn't reproduce if I either
1) add noinline to copy_signal, so we are not patching the whole
   copy_process function;
or
2) Switch compiler from gcc 14.2.1 to gcc 11.5.0.

So it appears something in gcc 14.2.1 is causing live patch to fail
for copy_process().

Thanks,
Song

[...]