Re: git: 64a73d1b6dc9 - main - amd64/*sigtramp.S: re-enable some cfi annotations for special registers

On Wed, Sep 23, 2026 at 10:26:12AM +0200, Herbert J. Skuhra wrote:
> On Wed, 23 Sep 2026 10:17:37 +0200, Konstantin Belousov wrote:
> > 
> > On Wed, Sep 23, 2026 at 09:37:06AM +0200, Herbert J. Skuhra wrote:
> > > On Mon, 21 Sep 2026 20:26:56 +0200, Konstantin Belousov wrote:
> > > > 
> > > > The branch main has been updated by kib:
> > > > 
> > > > URL: https://cgit.FreeBSD.org/src/commit/?id=64a73d1b6dc93d92daea1e2d0603fda1dddadf4a
> > > > 
> > > > commit 64a73d1b6dc93d92daea1e2d0603fda1dddadf4a
> > > > Author:     Konstantin Belousov <kib@FreeBSD.org>
> > > > AuthorDate: 2026-09-19 09:46:19 +0000
> > > > Commit:     Konstantin Belousov <kib@FreeBSD.org>
> > > > CommitDate: 2026-09-21 18:25:38 +0000
> > > > 
> > > >     amd64/*sigtramp.S: re-enable some cfi annotations for special registers
> > > >     
> > > >     Also explicitly specify .cfi_sections to emit the cfi bytecode into the
> > > >     loadable .eh_frame section.
> > > >     
> > > >     Reviewed by:    mchoo
> > > >     Sponsored by:   The FreeBSD Foundation
> > > >     MFC after:      1 week
> > > >     Differential revision:  https://reviews.freebsd.org/D59838
> > > > ---
> > > >  sys/amd64/amd64/sigtramp.S     | 44 ++++++++++++++++++++++++++----------------
> > > >  sys/amd64/ia32/ia32_sigtramp.S | 19 ++++++++++++------
> > > >  2 files changed, 40 insertions(+), 23 deletions(-)
> > > 
> > > After this commit I get:
> > > 
> > > Sep 23 09:18:52 srv01 kernel: pid 79694 (tmux), jid 0, uid 1001: exited on signal 11 (core dumped)
> > > Sep 23 09:18:56 srv01 sshd-session[78306]: error: mm_reap: child terminated by signal 11
> > > Sep 23 09:18:57 srv01 kernel: pid 78765 (sshd-session), jid 0, uid 1001: exited on signal 11 (no core dump - sugid process denied by kern.sugid_coredump)
> > > Sep 23 09:18:57 srv01 kernel: pid 70073 (sshd), jid 0, uid 0: exited on signal 11 (no core dump - sugid process denied by kern.sugid_coredump)
> > > 
> > > This is a (K)VM.
> > 
> > How did you determined that the commit is the problem?
> > The change you cited did not modified a single executable instruction.
> 
> 1. git bisect
> 2. Running main-n289555-c7b67985633c with 64a73d1b6dc9
> reverted resolves the issue (no more core dumps).
As I said, the revision did not change any executable pathes in the code.
More, it only adjusted the stack unwinding info for the signal frames.