For some reason I missed the updated patch. On Fri, Mar 01, 2024 at 10:19:24AM +0800, Yaxiong Tian wrote: > From: Yaxiong Tian <[email protected]> > > On ARM64 machines using UEFI, if can_set_direct_map() return false by > setting some CONFIGS in kernel build or grub,such as > NO CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT、NO CONFIG_KFENCE > NO CONFIG_RODATA_FULL_DEFAULT_ENABLED.Also with setting rodata=off、 > debug_pagealloc=off in grub and NO CONFIG_KFENCE. > swsusp_save() will fail due to can't finding the map table under the > nomap memory.such as: [...] > [ 48.532162] Call trace: > [ 48.532162] swsusp_save+0x280/0x538 > [ 48.532162] swsusp_arch_suspend+0x148/0x190 > [ 48.532162] hibernation_snapshot+0x240/0x39c > [ 48.532162] hibernate+0xc4/0x378 > [ 48.532162] state_store+0xf0/0x10c > [ 48.532162] kobj_attr_store+0x14/0x24 > > This issue can be reproduced in QEMU using UEFI when booting with > rodata=off、debug_pagealloc=off in grub and NO CONFIG_KFENCE. > > This is because in swsusp_save()->copy_data_pages()->page_is_saveable(), > kernel_page_present() presumes that a page is present when > can_set_direct_map() > returns false even for NOMAP ranges.So NOMAP pages will saved in after,and > then > cause level3 translation fault in this pages.
I can see how kernel_page_present() ended up returning true if !can_set_direct_map(), though based on the function naming only, it feels a bit unintuitive. Is arm64 the only architecture making use of MEMBLOCK_NOMAP? Or is it the only one where kernel_page_present() also returns true if !can_set_direct_map()? > diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c > index 02870beb271e..d90005de1d26 100644 > --- a/arch/arm64/kernel/hibernate.c > +++ b/arch/arm64/kernel/hibernate.c > @@ -94,7 +94,7 @@ int pfn_is_nosave(unsigned long pfn) > unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1); > > return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn)) || > - crash_is_nosave(pfn); > + crash_is_nosave(pfn) || !pfn_is_map_memory(pfn); > } This indeed fixes the problem but it looks like an arm64-specific workaround. I can see at least arm, loongarch and riscv making use of memblock_is_map_memory() (which is what pfn_is_map_memory() calls). Do they not have the same problem? On riscv, for example, kernel_page_present() does not depend on any ARCH_HAS_SET_DIRECT_MAP related options/conditions (neither does x86 though not sure it cares about MEMBLOCK_NOMAP). Should we do the same for arm64 and drop the !can_set_direct_map() condition in kernel_page_present()? -- Catalin
