On Fri, Dec 19, 2025 at 3:41 PM Mike Rapoport <[email protected]> wrote: > > On Thu, Dec 18, 2025 at 10:08:54PM -0500, Pasha Tatashin wrote: > > If the previous kernel enabled KHO but did not call kho_finalize() > > (e.g., CONFIG_LIVEUPDATE=n or userspace skipped the finalization step), > > the 'preserved-memory-map' property in the FDT remains empty/zero. > > > > Previously, kho_populate() would succeed regardless of the memory map's > > state, reserving the incoming scratch regions in memblock. However, > > kho_memory_init() would later fail to deserialize the empty map. By that > > time, the scratch regions were already registered, leading to partial > > initialization and subsequent list corruption (double-free) during > > kho_init(). > > > > Move the validation of the preserved memory map earlier into > > kho_populate(). If the memory map is empty/NULL: > > 1. Abort kho_populate() immediately with -ENOENT. > > 2. Do not register or reserve the incoming scratch memory, allowing the new > > kernel to reclaim those pages as standard free memory. > > 3. Leave the global 'kho_in' state uninitialized. > > > > Consequently, kho_memory_init() sees no active KHO context > > (kho_in.mem_chunks_phys is 0) and falls back to kho_reserve_scratch(), > > allocating fresh scratch memory as if it were a standard cold boot. > > > > Fixes: de51999e687c ("kho: allow memory preservation state updates after > > finalization") > > Reported-by: Ricardo <[email protected]> > > I believe Ricardo has a real email ;-)
Oops :-) > > > Closes: > > https://lore.kernel.org/all/[email protected] > > Signed-off-by: Pasha Tatashin <[email protected]> > > --- > > Changes v2: > > - Removed phys_to_virt() from kho_populate(). > > > > kernel/liveupdate/kexec_handover.c | 39 ++++++++++++++++-------------- > > 1 file changed, 21 insertions(+), 18 deletions(-) > > > > diff --git a/kernel/liveupdate/kexec_handover.c > > b/kernel/liveupdate/kexec_handover.c > > index 9dc51fab604f..6ba554208c81 100644 > > --- a/kernel/liveupdate/kexec_handover.c > > +++ b/kernel/liveupdate/kexec_handover.c > > @@ -460,27 +460,23 @@ static void __init deserialize_bitmap(unsigned int > > order, > > } > > } > > > > -/* Return true if memory was deserizlied */ > > -static bool __init kho_mem_deserialize(const void *fdt) > > +/* Returns head of preserved physical memory chunks pointer from FDT */ > > +static phys_addr_t __init kho_get_mem_chunks_phys(const void *fdt) > > Let's s/mem_chunks/mem_map/ everywhere please. > And the comment would become > > /* Returns physical address of the preserved memory map from FDT */ Sure, I will send version 3 soon. > > Other than that > > Reviewed-by: Mike Rapoport (Microsoft) <[email protected]> Thanks, Pasha
