On Mon, Nov 24 2025, [email protected] wrote: > From: Ran Xiaokai <[email protected]> > > When booting with debug_pagealloc=on while having: > CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT=y > CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=n > the system fails to boot due to page faults during kmemleak scanning. > > This occurs because: > With debug_pagealloc is enabled, __free_pages() invokes > debug_pagealloc_unmap_pages(), clearing the _PAGE_PRESENT bit for > freed pages in the kernel page table. > KHO scratch areas are allocated from memblock and noted by kmemleak. But > these areas don't remain reserved but released later to the page allocator > using init_cma_reserved_pageblock(). This causes subsequent kmemleak scans > access non-PRESENT pages, leading to fatal page faults. > > Mark scratch areas with kmemleak_ignore_phys() after they are allocated > from memblock to exclude them from kmemleak scanning before they are > released to buddy allocator to fix this. > > Fixes: 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers") > Signed-off-by: Ran Xiaokai <[email protected]> > Reviewed-by: Mike Rapoport (Microsoft) <[email protected]> > --- > kernel/liveupdate/kexec_handover.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/liveupdate/kexec_handover.c > b/kernel/liveupdate/kexec_handover.c > index 224bdf5becb6..c729d455ee7b 100644 > --- a/kernel/liveupdate/kexec_handover.c > +++ b/kernel/liveupdate/kexec_handover.c > @@ -11,6 +11,7 @@ > > #include <linux/cleanup.h> > #include <linux/cma.h> > +#include <linux/kmemleak.h> > #include <linux/count_zeros.h> > #include <linux/kexec.h> > #include <linux/kexec_handover.h> > @@ -1369,6 +1370,7 @@ static __init int kho_init(void) > unsigned long count = kho_scratch[i].size >> PAGE_SHIFT; > unsigned long pfn; > > + kmemleak_ignore_phys(kho_scratch[i].addr);
Can you please put the explanation you gave in [0] for why this is not necessary in KHO boot as a comment here? After that, Reviewed-by: Pratyush Yadav <[email protected]> [0] https://lore.kernel.org/all/[email protected]/ > for (pfn = base_pfn; pfn < base_pfn + count; > pfn += pageblock_nr_pages) > init_cma_reserved_pageblock(pfn_to_page(pfn)); -- Regards, Pratyush Yadav
