Re: [PATCH 0/4] vmcore-tasks: export per-task metadata to vmcoreinfo

From: Simon Horman <horms@kernel.org>
To: Mike Rapoport <rppt@kernel.org>
Cc: Pnina Feder <pnina.feder@mobileye.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Baoquan He <baoquan.he@linux.dev>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	Pratyush Yadav <pratyush@kernel.org>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Dave Young <ruirui.yang@linux.dev>,
	Jonathan Corbet <corbet@lwn.net>, Alexandre Ghiti <alex@ghiti.fr>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-doc@vger.kernel.org
Subject: Re: [PATCH 0/4] vmcore-tasks: export per-task metadata to vmcoreinfo
Date: Tue, 21 Jul 2026 12:13:30 +0100	[thread overview]
Message-ID: <20260721111330.GA1768252@horms.kernel.org> (raw)
In-Reply-To: <al4X300UObXawEIJ@kernel.org>

On Mon, Jul 20, 2026 at 03:43:11PM +0300, Mike Rapoport wrote:
> Hi Simon,
> 
> On Mon, Jul 20, 2026 at 10:19:27AM +0100, Simon Horman wrote:
> > On Tue, Jul 07, 2026 at 09:21:58AM +0300, Mike Rapoport wrote:
> > > On Tue, Jun 23, 2026 at 12:14:26AM +0300, Pnina Feder wrote:
> > > > This series extends vmcoreinfo with struct offsets and sizes needed by
> > > > the vmcore-tasks userspace tool to extract per-task state from a vmcore
> > > > dump without requiring kernel debug symbols (DWARF/BTF).
> > > > 
> > > > The vmcore-tasks tool reads /proc/vmcore (or a saved vmcore file) and
> > > > reconstructs, for each task:
> > > >   - task name, pid, state, flags
> > > >   - VMA list (start, end, flags, backing file)
> > > >   - user register state (saved on the kernel stack at kernel entry)
> > > >   - user-space backtrace with VMA/filename mapping
> > > >   - kernel dmesg buffer
> > > > 
> > > > This provides a lightweight post-mortem crash analysis capability for
> > > > production environments where full debug info (DWARF/BTF) is not
> > > > available.
> > > > 
> > > > The companion userspace tool is submitted to kexec-tools:
> > > >   https://lore.kernel.org/all/20260622205550.1087163-1-pnina.feder@mobileye.com/
> > > 
> > > Sorry for the delay, this fell between the cracks somehow.
> > > 
> > > The kernel side looks fine overall, but to merge it there should be an
> > > agreement from the userspace side maintainers that vmcore-tasks is
> > > something they are wishing to accept.
> > 
> > Hi Mike, all,
> > 
> > Sorry for the extended delay.
> > 
> > I will send some minor feedback to the user-space tool patchset
> > but overall, yes, this is something I would be happy to accept.
> > 
> > I don't want to create a chicken-and-egg type problem here.
> > But it's probably worth mentioning that usually features
> > hit the kernel before the corresponding code is accepted
> > into kexec-tools.
> 
> Sorry if I wasn't clear. 
> 
> I didn't mean that the feature should be merged into kexec-tools before
> merging the kernel bits. I just wanted to make sure there's no fundamental
> issue from kexec-tools perspective.

Thanks, it is clear :)

> > Let me know how you would like to proceed.
> 
> I'm going to wait for Baoquan's review and once that's done I'll pick up
> the kernel bits.

I see that conversation is now active.

Thanks to all.