| Message ID | 20230411141818.62152-1-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/2] mm/vmemmap/devdax: Fix kernel crash when probing devdax devices | expand |
On 11/04/2023 15:18, Aneesh Kumar K.V wrote: > commit 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory savings for compound > devmaps") added support for using optimized vmmemap for devdax devices. But how > vmemmap mappings are created are architecture specific. For example, powerpc > with hash translation doesn't have vmemmap mappings in init_mm page table > instead they are bolted table entries in the hardware page table > > vmemmap_populate_compound_pages() used by vmemmap optimization code is not aware > of these architecture-specific mapping. Hence allow architecture to opt for this > feature. I selected architectures supporting HUGETLB_PAGE_OPTIMIZE_VMEMMAP > option as also supporting this feature. > Perhaps rephrase last sentence to be in imperative form e.g.: Architectures supporting HUGETLB_PAGE_OPTIMIZE_VMEMMAP option are selected when supporting this feature. > This patch fixes the below crash on ppc64. > Avoid the 'This patch' per submission guidelines e.g. 'On ppc64 (pmem) where this isn't supported, it fixes below crash:' > BUG: Unable to handle kernel data access on write at 0xc00c000100400038 > Faulting instruction address: 0xc000000001269d90 > Oops: Kernel access of bad area, sig: 11 [#1] > LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries > Modules linked in: > CPU: 7 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc5-150500.34-default+ #2 5c90a668b6bbd142599890245c2fb5de19d7d28a > Hardware name: IBM,9009-42G POWER9 (raw) 0x4e0202 0xf000005 of:IBM,FW950.40 (VL950_099) hv:phyp pSeries > NIP: c000000001269d90 LR: c0000000004c57d4 CTR: 0000000000000000 > REGS: c000000003632c30 TRAP: 0300 Not tainted (6.3.0-rc5-150500.34-default+) > MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24842228 XER: 00000000 > CFAR: c0000000004c57d0 DAR: c00c000100400038 DSISR: 42000000 IRQMASK: 0 > .... > NIP [c000000001269d90] __init_single_page.isra.74+0x14/0x4c > LR [c0000000004c57d4] __init_zone_device_page+0x44/0xd0 > Call Trace: > [c000000003632ed0] [c000000003632f60] 0xc000000003632f60 (unreliable) > [c000000003632f10] [c0000000004c5ca0] memmap_init_zone_device+0x170/0x250 > [c000000003632fe0] [c0000000005575f8] memremap_pages+0x2c8/0x7f0 > [c0000000036330c0] [c000000000557b5c] devm_memremap_pages+0x3c/0xa0 > [c000000003633100] [c000000000d458a8] dev_dax_probe+0x108/0x3e0 > [c0000000036331a0] [c000000000d41430] dax_bus_probe+0xb0/0x140 > [c0000000036331d0] [c000000000cef27c] really_probe+0x19c/0x520 > [c000000003633260] [c000000000cef6b4] __driver_probe_device+0xb4/0x230 > [c0000000036332e0] [c000000000cef888] driver_probe_device+0x58/0x120 > [c000000003633320] [c000000000cefa6c] __device_attach_driver+0x11c/0x1e0 > [c0000000036333a0] [c000000000cebc58] bus_for_each_drv+0xa8/0x130 > [c000000003633400] [c000000000ceefcc] __device_attach+0x15c/0x250 > [c0000000036334a0] [c000000000ced458] bus_probe_device+0x108/0x110 > [c0000000036334f0] [c000000000ce92dc] device_add+0x7fc/0xa10 > [c0000000036335b0] [c000000000d447c8] devm_create_dev_dax+0x1d8/0x530 > [c000000003633640] [c000000000d46b60] __dax_pmem_probe+0x200/0x270 > [c0000000036337b0] [c000000000d46bf0] dax_pmem_probe+0x20/0x70 > [c0000000036337d0] [c000000000d2279c] nvdimm_bus_probe+0xac/0x2b0 > [c000000003633860] [c000000000cef27c] really_probe+0x19c/0x520 > [c0000000036338f0] [c000000000cef6b4] __driver_probe_device+0xb4/0x230 > [c000000003633970] [c000000000cef888] driver_probe_device+0x58/0x120 > [c0000000036339b0] [c000000000cefd08] __driver_attach+0x1d8/0x240 > [c000000003633a30] [c000000000cebb04] bus_for_each_dev+0xb4/0x130 > [c000000003633a90] [c000000000cee564] driver_attach+0x34/0x50 > [c000000003633ab0] [c000000000ced878] bus_add_driver+0x218/0x300 > [c000000003633b40] [c000000000cf1144] driver_register+0xa4/0x1b0 > [c000000003633bb0] [c000000000d21a0c] __nd_driver_register+0x5c/0x100 > [c000000003633c10] [c00000000206a2e8] dax_pmem_init+0x34/0x48 > [c000000003633c30] [c0000000000132d0] do_one_initcall+0x60/0x320 > [c000000003633d00] [c0000000020051b0] kernel_init_freeable+0x360/0x400 > [c000000003633de0] [c000000000013764] kernel_init+0x34/0x1d0 > [c000000003633e50] [c00000000000de14] ret_from_kernel_thread+0x5c/0x64 > > Fixes: 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory savings for compound devmaps") > Cc: Joao Martins <joao.m.martins@oracle.com> > Cc: Muchun Song <songmuchun@bytedance.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Reported-by: Tarun Sahu <tsahu@linux.ibm.com> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > --- > changes from V1: > * Only disable memory saving part of compound devmaps > * Update the correct Fixes: commit > * Add patch to drop HUGETLB specific kconfig > > include/linux/mm.h | 16 ++++++++++++++++ > mm/page_alloc.c | 9 ++++++--- > mm/sparse-vmemmap.c | 3 +-- > 3 files changed, 23 insertions(+), 5 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 716d30d93616..c47f2186d2c2 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3442,6 +3442,22 @@ void vmemmap_populate_print_last(void); > void vmemmap_free(unsigned long start, unsigned long end, > struct vmem_altmap *altmap); > #endif > + > +#ifdef CONFIG_ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMA You are missing a 'P' > +static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, > + struct dev_pagemap *pgmap) > +{ > + return is_power_of_2(sizeof(struct page)) && > + pgmap && (pgmap_vmemmap_nr(pgmap) > 1) && !altmap; > +} > +#else > +static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, > + struct dev_pagemap *pgmap) > +{ > + return false; > +} > +#endif > + > void register_page_bootmem_memmap(unsigned long section_nr, struct page *map, > unsigned long nr_pages); > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3bb3484563ed..292411d8816f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6844,10 +6844,13 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, > * of an altmap. See vmemmap_populate_compound_pages(). > */ > static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, > + struct dev_pagemap *pgmap, > unsigned long nr_pages) > { > - return is_power_of_2(sizeof(struct page)) && > - !altmap ? 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages; > + if (vmemmap_can_optimize(altmap, pgmap)) > + return 2 * (PAGE_SIZE / sizeof(struct page)); > + else > + return nr_pages; > } > Keep the ternary operator as already is the case for compound_nr_pages to avoid doing too much in one patch: return vmemmap_can_optimize(altmap, pgmap) ? 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages; Or you really want to remove the ternary operator perhaps take the unnecessary else and make the long line be less indented: if (!vmemmap_can_optimize(altmap, pgmap)) return nr_pages; return 2 * (PAGE_SIZE / sizeof(struct page)); I don't think the latter is a significant improvement over the ternary one. But I guess that's a matter of preferred style. > static void __ref memmap_init_compound(struct page *head, > @@ -6912,7 +6915,7 @@ void __ref memmap_init_zone_device(struct zone *zone, > continue; > > memmap_init_compound(page, pfn, zone_idx, nid, pgmap, > - compound_nr_pages(altmap, pfns_per_compound)); > + compound_nr_pages(altmap, pgmap, pfns_per_compound)); > } > > pr_info("%s initialised %lu pages in %ums\n", __func__, > diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c > index c5398a5960d0..10d73a0dfcec 100644 > --- a/mm/sparse-vmemmap.c > +++ b/mm/sparse-vmemmap.c > @@ -458,8 +458,7 @@ struct page * __meminit __populate_section_memmap(unsigned long pfn, > !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) > return NULL; > > - if (is_power_of_2(sizeof(struct page)) && > - pgmap && pgmap_vmemmap_nr(pgmap) > 1 && !altmap) > + if (vmemmap_can_optimize(altmap, pgmap)) > r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); > else > r = vmemmap_populate(start, end, nid, altmap);
Joao Martins <joao.m.martins@oracle.com> writes: > On 11/04/2023 15:18, Aneesh Kumar K.V wrote: >> commit 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory savings for compound >> devmaps") added support for using optimized vmmemap for devdax devices. But how >> vmemmap mappings are created are architecture specific. For example, powerpc >> with hash translation doesn't have vmemmap mappings in init_mm page table >> instead they are bolted table entries in the hardware page table >> >> vmemmap_populate_compound_pages() used by vmemmap optimization code is not aware >> of these architecture-specific mapping. Hence allow architecture to opt for this >> feature. I selected architectures supporting HUGETLB_PAGE_OPTIMIZE_VMEMMAP >> option as also supporting this feature. >> > Perhaps rephrase last sentence to be in imperative form e.g.: > > Architectures supporting HUGETLB_PAGE_OPTIMIZE_VMEMMAP option are selected when > supporting this feature. > >> This patch fixes the below crash on ppc64. >> > Avoid the 'This patch' per submission guidelines e.g. > > 'On ppc64 (pmem) where this isn't supported, it fixes below crash:' ok will update in the next version. > >> BUG: Unable to handle kernel data access on write at 0xc00c000100400038 >> Faulting instruction address: 0xc000000001269d90 >> Oops: Kernel access of bad area, sig: 11 [#1] >> LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries >> Modules linked in: > ... >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index 716d30d93616..c47f2186d2c2 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -3442,6 +3442,22 @@ void vmemmap_populate_print_last(void); >> void vmemmap_free(unsigned long start, unsigned long end, >> struct vmem_altmap *altmap); >> #endif >> + >> +#ifdef CONFIG_ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMA > > You are missing a 'P' I noticed that after sending v2 and sent v2-updated with that change. > >> +static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, >> + struct dev_pagemap *pgmap) >> +{ >> + return is_power_of_2(sizeof(struct page)) && >> + pgmap && (pgmap_vmemmap_nr(pgmap) > 1) && !altmap; >> +} >> +#else >> +static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, >> + struct dev_pagemap *pgmap) >> +{ >> + return false; >> +} >> +#endif >> + >> void register_page_bootmem_memmap(unsigned long section_nr, struct page *map, >> unsigned long nr_pages); >> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 3bb3484563ed..292411d8816f 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -6844,10 +6844,13 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, >> * of an altmap. See vmemmap_populate_compound_pages(). >> */ >> static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, >> + struct dev_pagemap *pgmap, >> unsigned long nr_pages) >> { >> - return is_power_of_2(sizeof(struct page)) && >> - !altmap ? 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages; >> + if (vmemmap_can_optimize(altmap, pgmap)) >> + return 2 * (PAGE_SIZE / sizeof(struct page)); >> + else >> + return nr_pages; >> } >> > > Keep the ternary operator as already is the case for compound_nr_pages to avoid > doing too much in one patch: > > return vmemmap_can_optimize(altmap, pgmap) ? > 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages; > > Or you really want to remove the ternary operator perhaps take the unnecessary > else and make the long line be less indented: > > if (!vmemmap_can_optimize(altmap, pgmap)) > return nr_pages; > > return 2 * (PAGE_SIZE / sizeof(struct page)); > > I don't think the latter is a significant improvement over the ternary one. But > I guess that's a matter of preferred style. How about static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, struct dev_pagemap *pgmap) { if (!vmemmap_can_optimize(altmap, pgmap)) return pgmap_vmemmap_nr(pgmap); return 2 * (PAGE_SIZE / sizeof(struct page)); } > >> static void __ref memmap_init_compound(struct page *head, >> @@ -6912,7 +6915,7 @@ void __ref memmap_init_zone_device(struct zone *zone, >> continue; >> >> memmap_init_compound(page, pfn, zone_idx, nid, pgmap, >> - compound_nr_pages(altmap, pfns_per_compound)); >> + compound_nr_pages(altmap, pgmap, pfns_per_compound)); >> } >> >> pr_info("%s initialised %lu pages in %ums\n", __func__, >> diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c >> index c5398a5960d0..10d73a0dfcec 100644 >> --- a/mm/sparse-vmemmap.c >> +++ b/mm/sparse-vmemmap.c >> @@ -458,8 +458,7 @@ struct page * __meminit __populate_section_memmap(unsigned long pfn, >> !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) >> return NULL; >> >> - if (is_power_of_2(sizeof(struct page)) && >> - pgmap && pgmap_vmemmap_nr(pgmap) > 1 && !altmap) >> + if (vmemmap_can_optimize(altmap, pgmap)) >> r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); >> else >> r = vmemmap_populate(start, end, nid, altmap); -aneesh
On 11/04/2023 16:20, Aneesh Kumar K.V wrote: > Joao Martins <joao.m.martins@oracle.com> writes: >> On 11/04/2023 15:18, Aneesh Kumar K.V wrote: >>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >>> index 3bb3484563ed..292411d8816f 100644 >>> --- a/mm/page_alloc.c >>> +++ b/mm/page_alloc.c >>> @@ -6844,10 +6844,13 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, >>> * of an altmap. See vmemmap_populate_compound_pages(). >>> */ >>> static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, >>> + struct dev_pagemap *pgmap, >>> unsigned long nr_pages) >>> { >>> - return is_power_of_2(sizeof(struct page)) && >>> - !altmap ? 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages; >>> + if (vmemmap_can_optimize(altmap, pgmap)) >>> + return 2 * (PAGE_SIZE / sizeof(struct page)); >>> + else >>> + return nr_pages; >>> } >>> >> >> Keep the ternary operator as already is the case for compound_nr_pages to avoid >> doing too much in one patch: >> >> return vmemmap_can_optimize(altmap, pgmap) ? >> 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages; >> >> Or you really want to remove the ternary operator perhaps take the unnecessary >> else and make the long line be less indented: >> >> if (!vmemmap_can_optimize(altmap, pgmap)) >> return nr_pages; >> >> return 2 * (PAGE_SIZE / sizeof(struct page)); >> >> I don't think the latter is a significant improvement over the ternary one. But >> I guess that's a matter of preferred style. > > How about > > static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, > struct dev_pagemap *pgmap) > { > > if (!vmemmap_can_optimize(altmap, pgmap)) > return pgmap_vmemmap_nr(pgmap); > > return 2 * (PAGE_SIZE / sizeof(struct page)); > } > I am a bit more fond of the ternary option. But this snip above is fine as well, including with the s/nr_pages/pgmap_vmemmap_nr(pgmap)/ change you added.
diff --git a/include/linux/mm.h b/include/linux/mm.h index 716d30d93616..c47f2186d2c2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3442,6 +3442,22 @@ void vmemmap_populate_print_last(void); void vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap); #endif + +#ifdef CONFIG_ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMA +static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, + struct dev_pagemap *pgmap) +{ + return is_power_of_2(sizeof(struct page)) && + pgmap && (pgmap_vmemmap_nr(pgmap) > 1) && !altmap; +} +#else +static inline bool vmemmap_can_optimize(struct vmem_altmap *altmap, + struct dev_pagemap *pgmap) +{ + return false; +} +#endif + void register_page_bootmem_memmap(unsigned long section_nr, struct page *map, unsigned long nr_pages); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3bb3484563ed..292411d8816f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6844,10 +6844,13 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, * of an altmap. See vmemmap_populate_compound_pages(). */ static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap, + struct dev_pagemap *pgmap, unsigned long nr_pages) { - return is_power_of_2(sizeof(struct page)) && - !altmap ? 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages; + if (vmemmap_can_optimize(altmap, pgmap)) + return 2 * (PAGE_SIZE / sizeof(struct page)); + else + return nr_pages; } static void __ref memmap_init_compound(struct page *head, @@ -6912,7 +6915,7 @@ void __ref memmap_init_zone_device(struct zone *zone, continue; memmap_init_compound(page, pfn, zone_idx, nid, pgmap, - compound_nr_pages(altmap, pfns_per_compound)); + compound_nr_pages(altmap, pgmap, pfns_per_compound)); } pr_info("%s initialised %lu pages in %ums\n", __func__, diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index c5398a5960d0..10d73a0dfcec 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -458,8 +458,7 @@ struct page * __meminit __populate_section_memmap(unsigned long pfn, !IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) return NULL; - if (is_power_of_2(sizeof(struct page)) && - pgmap && pgmap_vmemmap_nr(pgmap) > 1 && !altmap) + if (vmemmap_can_optimize(altmap, pgmap)) r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); else r = vmemmap_populate(start, end, nid, altmap);
commit 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory savings for compound devmaps") added support for using optimized vmmemap for devdax devices. But how vmemmap mappings are created are architecture specific. For example, powerpc with hash translation doesn't have vmemmap mappings in init_mm page table instead they are bolted table entries in the hardware page table vmemmap_populate_compound_pages() used by vmemmap optimization code is not aware of these architecture-specific mapping. Hence allow architecture to opt for this feature. I selected architectures supporting HUGETLB_PAGE_OPTIMIZE_VMEMMAP option as also supporting this feature. This patch fixes the below crash on ppc64. BUG: Unable to handle kernel data access on write at 0xc00c000100400038 Faulting instruction address: 0xc000000001269d90 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 7 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc5-150500.34-default+ #2 5c90a668b6bbd142599890245c2fb5de19d7d28a Hardware name: IBM,9009-42G POWER9 (raw) 0x4e0202 0xf000005 of:IBM,FW950.40 (VL950_099) hv:phyp pSeries NIP: c000000001269d90 LR: c0000000004c57d4 CTR: 0000000000000000 REGS: c000000003632c30 TRAP: 0300 Not tainted (6.3.0-rc5-150500.34-default+) MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24842228 XER: 00000000 CFAR: c0000000004c57d0 DAR: c00c000100400038 DSISR: 42000000 IRQMASK: 0 .... NIP [c000000001269d90] __init_single_page.isra.74+0x14/0x4c LR [c0000000004c57d4] __init_zone_device_page+0x44/0xd0 Call Trace: [c000000003632ed0] [c000000003632f60] 0xc000000003632f60 (unreliable) [c000000003632f10] [c0000000004c5ca0] memmap_init_zone_device+0x170/0x250 [c000000003632fe0] [c0000000005575f8] memremap_pages+0x2c8/0x7f0 [c0000000036330c0] [c000000000557b5c] devm_memremap_pages+0x3c/0xa0 [c000000003633100] [c000000000d458a8] dev_dax_probe+0x108/0x3e0 [c0000000036331a0] [c000000000d41430] dax_bus_probe+0xb0/0x140 [c0000000036331d0] [c000000000cef27c] really_probe+0x19c/0x520 [c000000003633260] [c000000000cef6b4] __driver_probe_device+0xb4/0x230 [c0000000036332e0] [c000000000cef888] driver_probe_device+0x58/0x120 [c000000003633320] [c000000000cefa6c] __device_attach_driver+0x11c/0x1e0 [c0000000036333a0] [c000000000cebc58] bus_for_each_drv+0xa8/0x130 [c000000003633400] [c000000000ceefcc] __device_attach+0x15c/0x250 [c0000000036334a0] [c000000000ced458] bus_probe_device+0x108/0x110 [c0000000036334f0] [c000000000ce92dc] device_add+0x7fc/0xa10 [c0000000036335b0] [c000000000d447c8] devm_create_dev_dax+0x1d8/0x530 [c000000003633640] [c000000000d46b60] __dax_pmem_probe+0x200/0x270 [c0000000036337b0] [c000000000d46bf0] dax_pmem_probe+0x20/0x70 [c0000000036337d0] [c000000000d2279c] nvdimm_bus_probe+0xac/0x2b0 [c000000003633860] [c000000000cef27c] really_probe+0x19c/0x520 [c0000000036338f0] [c000000000cef6b4] __driver_probe_device+0xb4/0x230 [c000000003633970] [c000000000cef888] driver_probe_device+0x58/0x120 [c0000000036339b0] [c000000000cefd08] __driver_attach+0x1d8/0x240 [c000000003633a30] [c000000000cebb04] bus_for_each_dev+0xb4/0x130 [c000000003633a90] [c000000000cee564] driver_attach+0x34/0x50 [c000000003633ab0] [c000000000ced878] bus_add_driver+0x218/0x300 [c000000003633b40] [c000000000cf1144] driver_register+0xa4/0x1b0 [c000000003633bb0] [c000000000d21a0c] __nd_driver_register+0x5c/0x100 [c000000003633c10] [c00000000206a2e8] dax_pmem_init+0x34/0x48 [c000000003633c30] [c0000000000132d0] do_one_initcall+0x60/0x320 [c000000003633d00] [c0000000020051b0] kernel_init_freeable+0x360/0x400 [c000000003633de0] [c000000000013764] kernel_init+0x34/0x1d0 [c000000003633e50] [c00000000000de14] ret_from_kernel_thread+0x5c/0x64 Fixes: 4917f55b4ef9 ("mm/sparse-vmemmap: improve memory savings for compound devmaps") Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Dan Williams <dan.j.williams@intel.com> Reported-by: Tarun Sahu <tsahu@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- changes from V1: * Only disable memory saving part of compound devmaps * Update the correct Fixes: commit * Add patch to drop HUGETLB specific kconfig include/linux/mm.h | 16 ++++++++++++++++ mm/page_alloc.c | 9 ++++++--- mm/sparse-vmemmap.c | 3 +-- 3 files changed, 23 insertions(+), 5 deletions(-)