Date: Tue, 17 Feb 2026 20:17:33 +0000 From: Colin Percival <cperciva@tarsnap.com> To: Alan Somers <asomers@freebsd.org>, "Michael W. Lucas" <mwl@mwl.io> Cc: stable@freebsd.org Subject: Re: debugging 15.0-RELEASE kernel on 15.0p3? Message-ID: <0100019c6d403fd1-da0238e5-482d-4425-831a-e07fc73d1edc-000000@email.amazonses.com> In-Reply-To: <CAOtMX2gZSk8Zb4MPO6jXBYdp6ydGp_i-FDLo6g5qN7hKAc1L-A@mail.gmail.com> References: <aZTDdTAtZpdfzruf@mail.ratoperatedvehicle.com> <CAOtMX2gZSk8Zb4MPO6jXBYdp6ydGp_i-FDLo6g5qN7hKAc1L-A@mail.gmail.com>
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On 2/17/26 11:41, Alan Somers wrote: > On Tue, Feb 17, 2026 at 12:37 PM Michael W. Lucas <mwl@mwl.io> wrote: >> This host didn't have kernel debug symbols. I went to install them and >> discovered my host needed updates. Thoughtlessly, I grabbed the new >> kernel and the new symbols. >> >> Oops. You can't debug a 15.0 kernel on 15.0p3. >> >> bucket/var/crash;kgdb -n 0 >> kgdb: couldn't find a suitable kernel image >> >> I have a 15.0 boot environment I could boot into, if there's a way to >> install the debugging symbols? Or is there a way to pull the old >> kernel and debug symbols down on the current BE? >> >> On dch's advice I tried setting the pkg.conf URL: >> url: >> "pkg+https://cloudfront.aws.pkgbase.freebsd.org/FreeBSD:15:amd64/base_release_ >> 0/" >> but got: >> pkg: No SRV record found for the repo 'FreeBSD-base' That isn't going to work because pkg+https says "look up SRV records" and the cloudfront.aws.pkgbase.freebsd.org endpoint is *what the SRV record points at*. You could have used pkg+https://pkg.freebsd.org/, but that wasn't going to work anyway since the repo will give you the latest packages (aka the -p3 kernel). The older packages are actually still there, but there's no way for you to find them. > You can probably install the symbols from the DVD image. They're in > the kernel-dbg.txz dist set. That should work for you, since your > crash happened in 15.0. But the same technique wouldn't work if you > had crashed at, say, 15.0-p1. The DVD image is the way to go. Either from kernel-dbg.txz or from the pkgbase repo on the DVD image. But as Alan notes, this only works because you crashed on the original release. We should probably consider creating a separate stash of kernel debug packages so people can fetch a not-most-recent version if needed. I never thought about this until now. Oh, a third option is to boot up an EC2 15.0-RELEASE-p1 image ("base" or "cloud-init"; "small" doesn't have debug symbols). But I'm guessing you'd prefer to look at your panic locally. -- Colin Percival FreeBSD Release Engineering Lead & EC2 platform maintainer Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoidhome | help
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