The patch titled
Subject: mm/vmemmap/devdax: fix kernel crash when probing devdax devices
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Subject: mm/vmemmap/devdax: fix kernel crash when probing devdax devices
Date: Fri, 7 Apr 2023 17:53:53 +0530
commit c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound
pages") 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. I
added vmemmap_can_optimize() even though page_vmemmap_nr(pgmap) > 1 check
should filter architecture not supporting this. IMHO that brings clarity
to the code where we are populating vmemmap.
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
Link: https://lkml.kernel.org/r/20230407122353.12018-1-aneesh.kumar@xxxxxxxxxxxxx
Fixes: c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Reported-by: Tarun Sahu <tsahu@xxxxxxxxxxxxx>
Cc: Joao Martins <joao.m.martins@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Jane Chu <jane.chu@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/Kconfig | 1 +
arch/loongarch/Kconfig | 1 +
arch/s390/Kconfig | 1 +
arch/x86/Kconfig | 1 +
drivers/dax/device.c | 3 ++-
include/linux/mm.h | 16 ++++++++++++++++
mm/Kconfig | 3 +++
mm/sparse-vmemmap.c | 3 +--
8 files changed, 26 insertions(+), 3 deletions(-)
--- a/arch/arm64/Kconfig~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/arch/arm64/Kconfig
@@ -102,6 +102,7 @@ config ARM64
select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
select ARCH_WANT_LD_ORPHAN_WARN
select ARCH_WANTS_NO_INSTR
+ select ARCH_WANT_OPTIMIZE_VMEMMAP
select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARM_AMBA
--- a/arch/loongarch/Kconfig~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/arch/loongarch/Kconfig
@@ -56,6 +56,7 @@ config LOONGARCH
select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
select ARCH_WANT_LD_ORPHAN_WARN
select ARCH_WANTS_NO_INSTR
+ select ARCH_WANT_OPTIMIZE_VMEMMAP
select BUILDTIME_TABLE_SORT
select COMMON_CLK
select CPU_PM
--- a/arch/s390/Kconfig~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/arch/s390/Kconfig
@@ -127,6 +127,7 @@ config S390
select ARCH_WANT_DEFAULT_BPF_JIT
select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_OPTIMIZE_VMEMMAP
select BUILDTIME_TABLE_SORT
select CLONE_BACKWARDS2
select DMA_OPS if PCI
--- a/arch/x86/Kconfig~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/arch/x86/Kconfig
@@ -127,6 +127,7 @@ config X86
select ARCH_WANT_HUGE_PMD_SHARE
select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP if X86_64
select ARCH_WANT_LD_ORPHAN_WARN
+ select ARCH_WANT_OPTIMIZE_VMEMMAP if X86_64
select ARCH_WANTS_THP_SWAP if X86_64
select ARCH_HAS_PARANOID_L1D_FLUSH
select BUILDTIME_TABLE_SORT
--- a/drivers/dax/device.c~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/drivers/dax/device.c
@@ -448,7 +448,8 @@ int dev_dax_probe(struct dev_dax *dev_da
}
pgmap->type = MEMORY_DEVICE_GENERIC;
- if (dev_dax->align > PAGE_SIZE)
+ if (dev_dax->align > PAGE_SIZE &&
+ IS_ENABLED(CONFIG_ARCH_WANT_OPTIMIZE_VMEMMAP))
pgmap->vmemmap_shift =
order_base_2(dev_dax->align >> PAGE_SHIFT);
addr = devm_memremap_pages(dev, pgmap);
--- a/include/linux/mm.h~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/include/linux/mm.h
@@ -3425,6 +3425,22 @@ void vmemmap_populate_print_last(void);
void vmemmap_free(unsigned long start, unsigned long end,
struct vmem_altmap *altmap);
#endif
+
+#ifdef CONFIG_ARCH_WANT_OPTIMIZE_VMEMMAP
+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);
--- a/mm/Kconfig~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/mm/Kconfig
@@ -480,6 +480,9 @@ config SPARSEMEM_VMEMMAP
pfn_to_page and page_to_pfn operations. This is the most
efficient option when sufficient kernel resources are available.
+config ARCH_WANT_OPTIMIZE_VMEMMAP
+ bool
+
config HAVE_MEMBLOCK_PHYS_MAP
bool
--- a/mm/sparse-vmemmap.c~mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices
+++ a/mm/sparse-vmemmap.c
@@ -458,8 +458,7 @@ struct page * __meminit __populate_secti
!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);
_
Patches currently in -mm which might be from aneesh.kumar@xxxxxxxxxxxxx are
mm-vmemmap-devdax-fix-kernel-crash-when-probing-devdax-devices.patch
