On Mon, Dec 29, 2025 at 4:09 PM Pratyush Yadav <[email protected]> wrote: > > On Wed, Dec 24 2025, Fadouse wrote: > > > Hi Evangelos, Mike, Pasha, Pratyush, > > > > I independently hit a crash in the LUO/memfd restore path with > > CONFIG_DEFERRED_STRUCT_PAGE_INIT=y, on a local build based on dd9b004b7ff3 > > (x86_64 QEMU, 6.19.0-rc1 timeframe). > > How? config KEXEC_HANDOVER depends on !DEFERRED_STRUCT_PAGE_INIT. So you > shouldn't even be able to enable KHO or LUO with > CONFIG_DEFERRED_STRUCT_PAGE_INIT=y. Are you sure it is enabled?
I think, Fadouse reported a bug with this patch applied, not an upstream bug. Pasha > > > > > In my reproducer, stage1 preserves a memfd via LUO and kexecs into stage2; > > stage2 calls LIVEUPDATE_SESSION_FINISH without retrieving files. I observed > > a reliable crash in adjust_managed_page_count() from kho_restore_page(). > > > > Minimal excerpt: > > > > stage2: start > > stage2: retrieved session fd=4 > > BUG: unable to handle page fault for address: 0000000000001410 > > RIP: adjust_managed_page_count+0x29/0x40 > > Call Trace: > > kho_restore_page+0x18a/0x1c0 > > kho_restore_folio+0xe/0x60 > > memfd_luo_finish+0xe6/0x160 > > luo_file_finish+0x188/0x240 > > luo_session_finish+0x2c/0x80 > > luo_session_ioctl+0xf5/0x170 > > __x64_sys_ioctl+0x91/0xe0 > > > > Applying the patch in <[email protected]> makes the > > issue no longer reproduce for me. > > > > I can share full logs and the small two-stage initramfs reproducer if > > needed. > > > > Thanks, > > YanXin Li > > > > Tested-by: YanXin Li <[email protected]> > > > [...] > > -- > Regards, > Pratyush Yadav
