On Thu, Nov 20, 2025 at 02:41:47PM +0000, [email protected] wrote: > Subject: liveupdate: Fix boot failure due to kmemleak access to unmapped pages
Please prefix kexec handover patches with kho: rather than liveupdate. > 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 enabled, __free_pages() invokes > debug_pagealloc_unmap_pages(), clearing the _PAGE_PRESENT bit for > freed pages in the direct mapping. > Commit 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers") > releases the KHO scratch region via init_cma_reserved_pageblock(), > unmapping its physical pages. Subsequent kmemleak scanning accesses > these unmapped pages, triggering fatal page faults. > > Call kmemleak_no_scan_phys() from kho_reserve_scratch() to > exclude the reserved region from scanning before > it is released to the buddy allocator. > > Fixes: 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers") > Signed-off-by: Ran Xiaokai <[email protected]> > --- > kernel/liveupdate/kexec_handover.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/liveupdate/kexec_handover.c > b/kernel/liveupdate/kexec_handover.c > index 224bdf5becb6..dd4942d1d76c 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> > @@ -654,6 +655,7 @@ static void __init kho_reserve_scratch(void) > if (!addr) > goto err_free_scratch_desc; > > + kmemleak_no_scan_phys(addr); There's kmemleak_ignore_phys() that can be called after the scratch areas allocated from memblock and with that kmemleak should not access them. Take a look at __cma_declare_contiguous_nid(). > kho_scratch[i].addr = addr; > kho_scratch[i].size = size; > i++; -- Sincerely yours, Mike.
