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

Mike Rapoport <[email protected]> Mon, 20 Jul 2026 15:43:11 +0300
Newsgroups org.kernel.vger.linux-mips,org.infradead.lists.kexec,org.infradead.lists.linux-riscv,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
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/[email protected]/
> > 
> > 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.

> 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.

-- 
Sincerely yours,
Mike.