Hi Ritesh, On Fri, Feb 27, 2026 at 10:39:53PM +0530, Ritesh Harjani wrote: > Sourabh Jain <[email protected]> writes: > > > I noticed CMA init for fadump crashkernel memory is failing. > > > > [ 0.000000] cma: pageblock_order not yet initialized. Called during > > early boot? > > [ 0.000000] fadump: Failed to init cma area for firmware-assisted > > dump,-22 > > > > > > kernel command-line: > > BOOT_IMAGE=(ieee1275//vdevice/v-scsi@30000070/disk@8100000000000000,msdos2)/vmlinuz-7.0.0-rc1+ > > > > root=/dev/mapper/rhel_ltcden3--lp12-root ro > > rd.lvm.lv=rhel_ltcden3-lp12/root rd.lvm.lv=rhel_ltcden3-lp12/swap > > fadump=on crashkernel=3G > > > > > > Same issue with kdump CMA reservation: > > > > [ 0.000000][ T0] cma: pageblock_order not yet initialized. Called > > during early boot? > > Good that we added those debug prints ;) > > I think I know what went wrong, as part of this arch,mm consolidation > patch series [1], I think the order of initialization is changed. > > With this patch the new order is ... > start_kernel() > - setup_arch() > - xxx_cma_reserve(); > - mm_core_init_early() > - free_area_init() > - sparse_init() > - set_pageblock_order() // this sets the pageblock_order. > > Whereas earlier set_pageblock_order() was called from initmem_init(), > just before cma reservations were being made. > > start_kernel() > - setup_arch() > - initmem_init() > - sparse_init() > - set_pageblock_order(); // this sets the pageblock_order > - xxx_cma_reserve(); > > So that means, pageblock_order is not initialized before these cma > reservation function calls, hence we are seeing these failures. > > setup_arch() { > ... > > /* > * Reserve large chunks of memory for use by CMA for kdump, fadump, KVM > and > * hugetlb. These must be called after initmem_init(), so that > * pageblock_order is initialised. > */ > fadump_cma_init(); > kdump_cma_reserve(); > kvm_cma_reserve(); > > ... > } > > > So what if we do.. > > start_kernel() { > ... > setup_arch(&command_line); > mm_core_init_early(); > setup_arch_post_mm_core_init(); // and here we call CMA reservation > functions ? Unless I'm missing something these cma reservations can be moved to arch_mm_preinit(). It runs after mm_core_init_early() and before memblock moves the free memory to the buddy.
> References: > [1]: > https://lore.kernel.org/linuxppc-dev/[email protected]/T/#m5adf1a845e0a0867066c4f7055f28e6304b73fa5 > [2]: > https://lore.kernel.org/all/3ae208e48c0d9cefe53d2dc4f593388067405b7d.1729146153.git.ritesh.l...@gmail.com/ > > > -ritesh -- Sincerely yours, Mike.
