[PATCH v3 0/3] arm64: support page mapping percpu first chunk allocator

[PATCH v3 0/3] arm64: support page mapping percpu first chunk allocator

[Kefeng Wang]

Percpu embedded first chunk allocator is the firstly option, but it
could fails on ARM64, eg,
  "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000"
  "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000"
  "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000"

then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838",
even the system could not boot successfully.

Let's implement page mapping percpu first chunk allocator as a fallback
to the embedding allocator to increase the robustness of the system.

Also fix a crash when both NEED_PER_CPU_PAGE_FIRST_CHUNK and KASAN_VMALLOC enabled.

Tested on ARM64 qemu with cmdline "percpu_alloc=page" based on v5.14-rc5.

v3:
- search for a range that fits instead of always picking the end from
  vmalloc area suggested by Catalin.
- use NUMA_NO_NODE to avoid "virt_to_phys used for non-linear address:"
  issue in arm64 kasan_populate_early_vm_area_shadow().
- add Acked-by: Marco Elver <elver@google.com> to patch v3

V2:
- fix build error when CONFIG_KASAN disabled, found by lkp@intel.com
- drop wrong __weak comment from kasan_populate_early_vm_area_shadow(),
  found by Marco Elver <elver@google.com>

Kefeng Wang (3):
  vmalloc: Choose a better start address in vm_area_register_early()
  arm64: Support page mapping percpu first chunk allocator
  kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

 arch/arm64/Kconfig         |  4 ++
 arch/arm64/mm/kasan_init.c | 16 ++++++++
 drivers/base/arch_numa.c   | 82 +++++++++++++++++++++++++++++++++-----
 include/linux/kasan.h      |  6 +++
 mm/kasan/init.c            |  5 +++
 mm/vmalloc.c               | 17 +++++---
 6 files changed, 115 insertions(+), 15 deletions(-)

-- 
2.26.2

[PATCH v3 1/3] vmalloc: Choose a better start address in vm_area_register_early()

[Kefeng Wang]

There are some fixed locations in the vmalloc area be reserved
in ARM(see iotable_init()) and ARM64(see map_kernel()), but for
pcpu_page_first_chunk(), it calls vm_area_register_early() and
choose VMALLOC_START as the start address of vmap area which
could be conflicted with above address, then could trigger a
BUG_ON in vm_area_add_early().

Let's choose the end of existing address range in vmlist as the
start address instead of VMALLOC_START to avoid the BUG_ON.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/vmalloc.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d5cd52805149..1e8fe08725b8 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2238,11 +2238,17 @@ void __init vm_area_add_early(struct vm_struct *vm)
  */
 void __init vm_area_register_early(struct vm_struct *vm, size_t align)
 {
-	static size_t vm_init_off __initdata;
-	unsigned long addr;
-
-	addr = ALIGN(VMALLOC_START + vm_init_off, align);
-	vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
+	struct vm_struct *head = vmlist, *curr, *next;
+	unsigned long addr = ALIGN(VMALLOC_START, align);
+
+	while (head != NULL) {
+		next = head->next;
+		curr = head;
+		head = next;
+		addr = ALIGN((unsigned long)curr->addr + curr->size, align);
+		if (next && (unsigned long)next->addr - addr > vm->size)
+			break;
+	}
 
 	vm->addr = (void *)addr;
 
-- 
2.26.2

[PATCH v3 2/3] arm64: Support page mapping percpu first chunk allocator

[Kefeng Wang]

Percpu embedded first chunk allocator is the firstly option, but it
could fails on ARM64, eg,
  "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000"
  "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000"
  "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000"

then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838",
even the system could not boot successfully.

Let's implement page mapping percpu first chunk allocator as a fallback
to the embedding allocator to increase the robustness of the system.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 arch/arm64/Kconfig       |  4 ++
 drivers/base/arch_numa.c | 82 +++++++++++++++++++++++++++++++++++-----
 2 files changed, 76 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fdcd54d39c1e..39f27e268c38 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1045,6 +1045,10 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
 	def_bool y
 	depends on NUMA
 
+config NEED_PER_CPU_PAGE_FIRST_CHUNK
+	def_bool y
+	depends on NUMA
+
 source "kernel/Kconfig.hz"
 
 config ARCH_SPARSEMEM_ENABLE
diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
index 4cc4e117727d..563b2013b75a 100644
--- a/drivers/base/arch_numa.c
+++ b/drivers/base/arch_numa.c
@@ -14,6 +14,7 @@
 #include <linux/of.h>
 
 #include <asm/sections.h>
+#include <asm/pgalloc.h>
 
 struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
 EXPORT_SYMBOL(node_data);
@@ -168,22 +169,83 @@ static void __init pcpu_fc_free(void *ptr, size_t size)
 	memblock_free_early(__pa(ptr), size);
 }
 
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+static void __init pcpu_populate_pte(unsigned long addr)
+{
+	pgd_t *pgd = pgd_offset_k(addr);
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	p4d = p4d_offset(pgd, addr);
+	if (p4d_none(*p4d)) {
+		pud_t *new;
+
+		new = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+		if (!new)
+			goto err_alloc;
+		p4d_populate(&init_mm, p4d, new);
+	}
+
+	pud = pud_offset(p4d, addr);
+	if (pud_none(*pud)) {
+		pmd_t *new;
+
+		new = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+		if (!new)
+			goto err_alloc;
+		pud_populate(&init_mm, pud, new);
+	}
+
+	pmd = pmd_offset(pud, addr);
+	if (!pmd_present(*pmd)) {
+		pte_t *new;
+
+		new = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+		if (!new)
+			goto err_alloc;
+		pmd_populate_kernel(&init_mm, pmd, new);
+	}
+
+	return;
+
+err_alloc:
+	panic("%s: Failed to allocate %lu bytes align=%lx from=%lx\n",
+	      __func__, PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
+}
+#endif
+
 void __init setup_per_cpu_areas(void)
 {
 	unsigned long delta;
 	unsigned int cpu;
-	int rc;
+	int rc = -EINVAL;
+
+	if (pcpu_chosen_fc != PCPU_FC_PAGE) {
+		/*
+		 * Always reserve area for module percpu variables.  That's
+		 * what the legacy allocator did.
+		 */
+		rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
+					    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
+					    pcpu_cpu_distance,
+					    pcpu_fc_alloc, pcpu_fc_free);
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+		if (rc < 0)
+			pr_warn("PERCPU: %s allocator failed (%d), falling back to page size\n",
+				   pcpu_fc_names[pcpu_chosen_fc], rc);
+#endif
+	}
 
-	/*
-	 * Always reserve area for module percpu variables.  That's
-	 * what the legacy allocator did.
-	 */
-	rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
-				    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
-				    pcpu_cpu_distance,
-				    pcpu_fc_alloc, pcpu_fc_free);
+#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
+	if (rc < 0)
+		rc = pcpu_page_first_chunk(PERCPU_MODULE_RESERVE,
+					   pcpu_fc_alloc,
+					   pcpu_fc_free,
+					   pcpu_populate_pte);
+#endif
 	if (rc < 0)
-		panic("Failed to initialize percpu areas.");
+		panic("Failed to initialize percpu areas (err=%d).", rc);
 
 	delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
 	for_each_possible_cpu(cpu)
-- 
2.26.2

[PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Kefeng Wang]

With KASAN_VMALLOC and NEED_PER_CPU_PAGE_FIRST_CHUNK, it crashs,

Unable to handle kernel paging request at virtual address ffff7000028f2000
...
swapper pgtable: 64k pages, 48-bit VAs, pgdp=0000000042440000
[ffff7000028f2000] pgd=000000063e7c0003, p4d=000000063e7c0003, pud=000000063e7c0003, pmd=000000063e7b0003, pte=0000000000000000
Internal error: Oops: 96000007 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.0-rc4-00003-gc6e6e28f3f30-dirty #62
Hardware name: linux,dummy-virt (DT)
pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO BTYPE=--)
pc : kasan_check_range+0x90/0x1a0
lr : memcpy+0x88/0xf4
sp : ffff80001378fe20
...
Call trace:
 kasan_check_range+0x90/0x1a0
 pcpu_page_first_chunk+0x3f0/0x568
 setup_per_cpu_areas+0xb8/0x184
 start_kernel+0x8c/0x328

The vm area used in vm_area_register_early() has no kasan shadow memory,
Let's add a new kasan_populate_early_vm_area_shadow() function to populate
the vm area shadow memory to fix the issue.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 arch/arm64/mm/kasan_init.c | 16 ++++++++++++++++
 include/linux/kasan.h      |  6 ++++++
 mm/kasan/init.c            |  5 +++++
 mm/vmalloc.c               |  1 +
 4 files changed, 28 insertions(+)

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 61b52a92b8b6..5b996ca4d996 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -287,6 +287,22 @@ static void __init kasan_init_depth(void)
 	init_task.kasan_depth = 0;
 }
 
+#ifdef CONFIG_KASAN_VMALLOC
+void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size)
+{
+	unsigned long shadow_start, shadow_end;
+
+	if (!is_vmalloc_or_module_addr(start))
+		return;
+
+	shadow_start = (unsigned long)kasan_mem_to_shadow(start);
+	shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE);
+	shadow_end = (unsigned long)kasan_mem_to_shadow(start + size);
+	shadow_end = ALIGN(shadow_end, PAGE_SIZE);
+	kasan_map_populate(shadow_start, shadow_end, NUMA_NO_NODE);
+}
+#endif
+
 void __init kasan_init(void)
 {
 	kasan_init_shadow();
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index dd874a1ee862..3f8c26d9ef82 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -133,6 +133,8 @@ struct kasan_cache {
 	bool is_kmalloc;
 };
 
+void kasan_populate_early_vm_area_shadow(void *start, unsigned long size);
+
 slab_flags_t __kasan_never_merge(void);
 static __always_inline slab_flags_t kasan_never_merge(void)
 {
@@ -303,6 +305,10 @@ void kasan_restore_multi_shot(bool enabled);
 
 #else /* CONFIG_KASAN */
 
+static inline void kasan_populate_early_vm_area_shadow(void *start,
+						       unsigned long size)
+{ }
+
 static inline slab_flags_t kasan_never_merge(void)
 {
 	return 0;
diff --git a/mm/kasan/init.c b/mm/kasan/init.c
index cc64ed6858c6..d39577d088a1 100644
--- a/mm/kasan/init.c
+++ b/mm/kasan/init.c
@@ -279,6 +279,11 @@ int __ref kasan_populate_early_shadow(const void *shadow_start,
 	return 0;
 }
 
+void __init __weak kasan_populate_early_vm_area_shadow(void *start,
+						       unsigned long size)
+{
+}
+
 static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
 {
 	pte_t *pte;
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 1e8fe08725b8..66a7e1ea2561 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2253,6 +2253,7 @@ void __init vm_area_register_early(struct vm_struct *vm, size_t align)
 	vm->addr = (void *)addr;
 
 	vm_area_add_early(vm);
+	kasan_populate_early_vm_area_shadow(vm->addr, vm->size);
 }
 
 static void vmap_init_free_space(void)
-- 
2.26.2

Re: [PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Kefeng Wang]

On 2021/8/9 17:37, Kefeng Wang wrote:
> With KASAN_VMALLOC and NEED_PER_CPU_PAGE_FIRST_CHUNK, it crashs,
>
> Unable to handle kernel paging request at virtual address ffff7000028f2000
> ...
> swapper pgtable: 64k pages, 48-bit VAs, pgdp=0000000042440000
> [ffff7000028f2000] pgd=000000063e7c0003, p4d=000000063e7c0003, pud=000000063e7c0003, pmd=000000063e7b0003, pte=0000000000000000
> Internal error: Oops: 96000007 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.0-rc4-00003-gc6e6e28f3f30-dirty #62
> Hardware name: linux,dummy-virt (DT)
> pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO BTYPE=--)
> pc : kasan_check_range+0x90/0x1a0
> lr : memcpy+0x88/0xf4
> sp : ffff80001378fe20
> ...
> Call trace:
>   kasan_check_range+0x90/0x1a0
>   pcpu_page_first_chunk+0x3f0/0x568
>   setup_per_cpu_areas+0xb8/0x184
>   start_kernel+0x8c/0x328
>
> The vm area used in vm_area_register_early() has no kasan shadow memory,
> Let's add a new kasan_populate_early_vm_area_shadow() function to populate
> the vm area shadow memory to fix the issue.

Should add Acked-by: Marco Elver <elver@google.com> [for KASAN parts] ,

missed here :(

> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   arch/arm64/mm/kasan_init.c | 16 ++++++++++++++++
>   include/linux/kasan.h      |  6 ++++++
>   mm/kasan/init.c            |  5 +++++
>   mm/vmalloc.c               |  1 +
>   4 files changed, 28 insertions(+)
>
> diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
> index 61b52a92b8b6..5b996ca4d996 100644
> --- a/arch/arm64/mm/kasan_init.c
> +++ b/arch/arm64/mm/kasan_init.c
> @@ -287,6 +287,22 @@ static void __init kasan_init_depth(void)
>   	init_task.kasan_depth = 0;
>   }
>   
> +#ifdef CONFIG_KASAN_VMALLOC
> +void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size)
> +{
> +	unsigned long shadow_start, shadow_end;
> +
> +	if (!is_vmalloc_or_module_addr(start))
> +		return;
> +
> +	shadow_start = (unsigned long)kasan_mem_to_shadow(start);
> +	shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE);
> +	shadow_end = (unsigned long)kasan_mem_to_shadow(start + size);
> +	shadow_end = ALIGN(shadow_end, PAGE_SIZE);
> +	kasan_map_populate(shadow_start, shadow_end, NUMA_NO_NODE);
> +}
> +#endif
> +
>   void __init kasan_init(void)
>   {
>   	kasan_init_shadow();
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index dd874a1ee862..3f8c26d9ef82 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -133,6 +133,8 @@ struct kasan_cache {
>   	bool is_kmalloc;
>   };
>   
> +void kasan_populate_early_vm_area_shadow(void *start, unsigned long size);
> +
>   slab_flags_t __kasan_never_merge(void);
>   static __always_inline slab_flags_t kasan_never_merge(void)
>   {
> @@ -303,6 +305,10 @@ void kasan_restore_multi_shot(bool enabled);
>   
>   #else /* CONFIG_KASAN */
>   
> +static inline void kasan_populate_early_vm_area_shadow(void *start,
> +						       unsigned long size)
> +{ }
> +
>   static inline slab_flags_t kasan_never_merge(void)
>   {
>   	return 0;
> diff --git a/mm/kasan/init.c b/mm/kasan/init.c
> index cc64ed6858c6..d39577d088a1 100644
> --- a/mm/kasan/init.c
> +++ b/mm/kasan/init.c
> @@ -279,6 +279,11 @@ int __ref kasan_populate_early_shadow(const void *shadow_start,
>   	return 0;
>   }
>   
> +void __init __weak kasan_populate_early_vm_area_shadow(void *start,
> +						       unsigned long size)
> +{
> +}
> +
>   static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
>   {
>   	pte_t *pte;
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 1e8fe08725b8..66a7e1ea2561 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2253,6 +2253,7 @@ void __init vm_area_register_early(struct vm_struct *vm, size_t align)
>   	vm->addr = (void *)addr;
>   
>   	vm_area_add_early(vm);
> +	kasan_populate_early_vm_area_shadow(vm->addr, vm->size);
>   }
>   
>   static void vmap_init_free_space(void)

Re: [PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Marco Elver]

On Mon, 9 Aug 2021 at 13:10, Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>
>
> On 2021/8/9 17:37, Kefeng Wang wrote:
> > With KASAN_VMALLOC and NEED_PER_CPU_PAGE_FIRST_CHUNK, it crashs,
> >
> > Unable to handle kernel paging request at virtual address ffff7000028f2000
> > ...
> > swapper pgtable: 64k pages, 48-bit VAs, pgdp=0000000042440000
> > [ffff7000028f2000] pgd=000000063e7c0003, p4d=000000063e7c0003, pud=000000063e7c0003, pmd=000000063e7b0003, pte=0000000000000000
> > Internal error: Oops: 96000007 [#1] PREEMPT SMP
> > Modules linked in:
> > CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.0-rc4-00003-gc6e6e28f3f30-dirty #62
> > Hardware name: linux,dummy-virt (DT)
> > pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO BTYPE=--)
> > pc : kasan_check_range+0x90/0x1a0
> > lr : memcpy+0x88/0xf4
> > sp : ffff80001378fe20
> > ...
> > Call trace:
> >   kasan_check_range+0x90/0x1a0
> >   pcpu_page_first_chunk+0x3f0/0x568
> >   setup_per_cpu_areas+0xb8/0x184
> >   start_kernel+0x8c/0x328
> >
> > The vm area used in vm_area_register_early() has no kasan shadow memory,
> > Let's add a new kasan_populate_early_vm_area_shadow() function to populate
> > the vm area shadow memory to fix the issue.
>
> Should add Acked-by: Marco Elver <elver@google.com> [for KASAN parts] ,

My Ack is still valid, thanks for noting.

> > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> > ---
> >   arch/arm64/mm/kasan_init.c | 16 ++++++++++++++++
> >   include/linux/kasan.h      |  6 ++++++
> >   mm/kasan/init.c            |  5 +++++
> >   mm/vmalloc.c               |  1 +
> >   4 files changed, 28 insertions(+)
> >
> > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
> > index 61b52a92b8b6..5b996ca4d996 100644
> > --- a/arch/arm64/mm/kasan_init.c
> > +++ b/arch/arm64/mm/kasan_init.c
> > @@ -287,6 +287,22 @@ static void __init kasan_init_depth(void)
> >       init_task.kasan_depth = 0;
> >   }
> >
> > +#ifdef CONFIG_KASAN_VMALLOC
> > +void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size)
> > +{
> > +     unsigned long shadow_start, shadow_end;
> > +
> > +     if (!is_vmalloc_or_module_addr(start))
> > +             return;
> > +
> > +     shadow_start = (unsigned long)kasan_mem_to_shadow(start);
> > +     shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE);
> > +     shadow_end = (unsigned long)kasan_mem_to_shadow(start + size);
> > +     shadow_end = ALIGN(shadow_end, PAGE_SIZE);
> > +     kasan_map_populate(shadow_start, shadow_end, NUMA_NO_NODE);
> > +}
> > +#endif
> > +
> >   void __init kasan_init(void)
> >   {
> >       kasan_init_shadow();
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index dd874a1ee862..3f8c26d9ef82 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> > @@ -133,6 +133,8 @@ struct kasan_cache {
> >       bool is_kmalloc;
> >   };
> >
> > +void kasan_populate_early_vm_area_shadow(void *start, unsigned long size);
> > +
> >   slab_flags_t __kasan_never_merge(void);
> >   static __always_inline slab_flags_t kasan_never_merge(void)
> >   {
> > @@ -303,6 +305,10 @@ void kasan_restore_multi_shot(bool enabled);
> >
> >   #else /* CONFIG_KASAN */
> >
> > +static inline void kasan_populate_early_vm_area_shadow(void *start,
> > +                                                    unsigned long size)
> > +{ }
> > +
> >   static inline slab_flags_t kasan_never_merge(void)
> >   {
> >       return 0;
> > diff --git a/mm/kasan/init.c b/mm/kasan/init.c
> > index cc64ed6858c6..d39577d088a1 100644
> > --- a/mm/kasan/init.c
> > +++ b/mm/kasan/init.c
> > @@ -279,6 +279,11 @@ int __ref kasan_populate_early_shadow(const void *shadow_start,
> >       return 0;
> >   }
> >
> > +void __init __weak kasan_populate_early_vm_area_shadow(void *start,
> > +                                                    unsigned long size)
> > +{
> > +}
> > +
> >   static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
> >   {
> >       pte_t *pte;
> > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> > index 1e8fe08725b8..66a7e1ea2561 100644
> > --- a/mm/vmalloc.c
> > +++ b/mm/vmalloc.c
> > @@ -2253,6 +2253,7 @@ void __init vm_area_register_early(struct vm_struct *vm, size_t align)
> >       vm->addr = (void *)addr;
> >
> >       vm_area_add_early(vm);
> > +     kasan_populate_early_vm_area_shadow(vm->addr, vm->size);
> >   }
> >
> >   static void vmap_init_free_space(void)

Re: [PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Kefeng Wang]

On 2021/8/9 19:21, Marco Elver wrote:
> On Mon, 9 Aug 2021 at 13:10, Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>>
>> On 2021/8/9 17:37, Kefeng Wang wrote:
>>> With KASAN_VMALLOC and NEED_PER_CPU_PAGE_FIRST_CHUNK, it crashs,
>>>
>>> Unable to handle kernel paging request at virtual address ffff7000028f2000
>>> ...
>>> swapper pgtable: 64k pages, 48-bit VAs, pgdp=0000000042440000
>>> [ffff7000028f2000] pgd=000000063e7c0003, p4d=000000063e7c0003, pud=000000063e7c0003, pmd=000000063e7b0003, pte=0000000000000000
>>> Internal error: Oops: 96000007 [#1] PREEMPT SMP
>>> Modules linked in:
>>> CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.0-rc4-00003-gc6e6e28f3f30-dirty #62
>>> Hardware name: linux,dummy-virt (DT)
>>> pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO BTYPE=--)
>>> pc : kasan_check_range+0x90/0x1a0
>>> lr : memcpy+0x88/0xf4
>>> sp : ffff80001378fe20
>>> ...
>>> Call trace:
>>>    kasan_check_range+0x90/0x1a0
>>>    pcpu_page_first_chunk+0x3f0/0x568
>>>    setup_per_cpu_areas+0xb8/0x184
>>>    start_kernel+0x8c/0x328
>>>
>>> The vm area used in vm_area_register_early() has no kasan shadow memory,
>>> Let's add a new kasan_populate_early_vm_area_shadow() function to populate
>>> the vm area shadow memory to fix the issue.
>> Should add Acked-by: Marco Elver <elver@google.com> [for KASAN parts] ,
> My Ack is still valid, thanks for noting.
Thanks,  Marco ;)

Re: [PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Andrey Konovalov]

On Mon, Aug 9, 2021 at 11:32 AM Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>
> With KASAN_VMALLOC and NEED_PER_CPU_PAGE_FIRST_CHUNK, it crashs,
>
> Unable to handle kernel paging request at virtual address ffff7000028f2000
> ...
> swapper pgtable: 64k pages, 48-bit VAs, pgdp=0000000042440000
> [ffff7000028f2000] pgd=000000063e7c0003, p4d=000000063e7c0003, pud=000000063e7c0003, pmd=000000063e7b0003, pte=0000000000000000
> Internal error: Oops: 96000007 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.0-rc4-00003-gc6e6e28f3f30-dirty #62
> Hardware name: linux,dummy-virt (DT)
> pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO BTYPE=--)
> pc : kasan_check_range+0x90/0x1a0
> lr : memcpy+0x88/0xf4
> sp : ffff80001378fe20
> ...
> Call trace:
>  kasan_check_range+0x90/0x1a0
>  pcpu_page_first_chunk+0x3f0/0x568
>  setup_per_cpu_areas+0xb8/0x184
>  start_kernel+0x8c/0x328
>
> The vm area used in vm_area_register_early() has no kasan shadow memory,
> Let's add a new kasan_populate_early_vm_area_shadow() function to populate
> the vm area shadow memory to fix the issue.
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>  arch/arm64/mm/kasan_init.c | 16 ++++++++++++++++
>  include/linux/kasan.h      |  6 ++++++
>  mm/kasan/init.c            |  5 +++++
>  mm/vmalloc.c               |  1 +
>  4 files changed, 28 insertions(+)
>
> diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
> index 61b52a92b8b6..5b996ca4d996 100644
> --- a/arch/arm64/mm/kasan_init.c
> +++ b/arch/arm64/mm/kasan_init.c
> @@ -287,6 +287,22 @@ static void __init kasan_init_depth(void)
>         init_task.kasan_depth = 0;
>  }
>
> +#ifdef CONFIG_KASAN_VMALLOC
> +void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size)
> +{
> +       unsigned long shadow_start, shadow_end;
> +
> +       if (!is_vmalloc_or_module_addr(start))
> +               return;
> +
> +       shadow_start = (unsigned long)kasan_mem_to_shadow(start);
> +       shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE);
> +       shadow_end = (unsigned long)kasan_mem_to_shadow(start + size);
> +       shadow_end = ALIGN(shadow_end, PAGE_SIZE);
> +       kasan_map_populate(shadow_start, shadow_end, NUMA_NO_NODE);
> +}
> +#endif
> +
>  void __init kasan_init(void)
>  {
>         kasan_init_shadow();
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index dd874a1ee862..3f8c26d9ef82 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -133,6 +133,8 @@ struct kasan_cache {
>         bool is_kmalloc;
>  };
>
> +void kasan_populate_early_vm_area_shadow(void *start, unsigned long size);
> +
>  slab_flags_t __kasan_never_merge(void);
>  static __always_inline slab_flags_t kasan_never_merge(void)
>  {
> @@ -303,6 +305,10 @@ void kasan_restore_multi_shot(bool enabled);
>
>  #else /* CONFIG_KASAN */
>
> +static inline void kasan_populate_early_vm_area_shadow(void *start,
> +                                                      unsigned long size)
> +{ }
> +
>  static inline slab_flags_t kasan_never_merge(void)
>  {
>         return 0;
> diff --git a/mm/kasan/init.c b/mm/kasan/init.c
> index cc64ed6858c6..d39577d088a1 100644
> --- a/mm/kasan/init.c
> +++ b/mm/kasan/init.c
> @@ -279,6 +279,11 @@ int __ref kasan_populate_early_shadow(const void *shadow_start,
>         return 0;
>  }
>
> +void __init __weak kasan_populate_early_vm_area_shadow(void *start,
> +                                                      unsigned long size)
> +{
> +}
> +
>  static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
>  {
>         pte_t *pte;
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 1e8fe08725b8..66a7e1ea2561 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2253,6 +2253,7 @@ void __init vm_area_register_early(struct vm_struct *vm, size_t align)
>         vm->addr = (void *)addr;
>
>         vm_area_add_early(vm);
> +       kasan_populate_early_vm_area_shadow(vm->addr, vm->size);
>  }
>
>  static void vmap_init_free_space(void)
> --
> 2.26.2
>

Acked-by: Andrey Konovalov <andreyknvl@gmail.com>

for KASAN parts.

Thanks!

Re: [PATCH v3 0/3] arm64: support page mapping percpu first chunk allocator

[Kefeng Wang]

Hi Catalin and Will，

The drivers/base/arch_numa.c is only shared by riscv and arm64,

and the change from patch2 won't broke riscv.

Could all patches be merged by arm64 tree? or any new comments?

Many thanks.

On 2021/8/9 17:37, Kefeng Wang wrote:
> Percpu embedded first chunk allocator is the firstly option, but it
> could fails on ARM64, eg,
>    "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000"
>    "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000"
>    "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000"
>
> then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838",
> even the system could not boot successfully.
>
> Let's implement page mapping percpu first chunk allocator as a fallback
> to the embedding allocator to increase the robustness of the system.
>
> Also fix a crash when both NEED_PER_CPU_PAGE_FIRST_CHUNK and KASAN_VMALLOC enabled.
>
> Tested on ARM64 qemu with cmdline "percpu_alloc=page" based on v5.14-rc5.
>
> v3:
> - search for a range that fits instead of always picking the end from
>    vmalloc area suggested by Catalin.
> - use NUMA_NO_NODE to avoid "virt_to_phys used for non-linear address:"
>    issue in arm64 kasan_populate_early_vm_area_shadow().
> - add Acked-by: Marco Elver <elver@google.com> to patch v3
>
> V2:
> - fix build error when CONFIG_KASAN disabled, found by lkp@intel.com
> - drop wrong __weak comment from kasan_populate_early_vm_area_shadow(),
>    found by Marco Elver <elver@google.com>
>
> Kefeng Wang (3):
>    vmalloc: Choose a better start address in vm_area_register_early()
>    arm64: Support page mapping percpu first chunk allocator
>    kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC
>
>   arch/arm64/Kconfig         |  4 ++
>   arch/arm64/mm/kasan_init.c | 16 ++++++++
>   drivers/base/arch_numa.c   | 82 +++++++++++++++++++++++++++++++++-----
>   include/linux/kasan.h      |  6 +++
>   mm/kasan/init.c            |  5 +++
>   mm/vmalloc.c               | 17 +++++---
>   6 files changed, 115 insertions(+), 15 deletions(-)
>

Re: [PATCH v3 0/3] arm64: support page mapping percpu first chunk allocator

[Kefeng Wang]

On 2021/8/12 14:07, Kefeng Wang wrote:
> Hi Catalin and Will，
>
> The drivers/base/arch_numa.c is only shared by riscv and arm64,
>
> and the change from patch2 won't broke riscv.
>
> Could all patches be merged by arm64 tree? or any new comments?

Kindly ping...

>
> Many thanks.
>
> On 2021/8/9 17:37, Kefeng Wang wrote:
>> Percpu embedded first chunk allocator is the firstly option, but it
>> could fails on ARM64, eg,
>>    "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 
>> 0x781fefff0000"
>>    "percpu: max_distance=0x600000540000 too large for vmalloc space 
>> 0x7dffb7ff0000"
>>    "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 
>> 0x5dffb7ff0000"
>>
>> then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 
>> pcpu_get_vm_areas+0x488/0x838",
>> even the system could not boot successfully.
>>
>> Let's implement page mapping percpu first chunk allocator as a fallback
>> to the embedding allocator to increase the robustness of the system.
>>
>> Also fix a crash when both NEED_PER_CPU_PAGE_FIRST_CHUNK and 
>> KASAN_VMALLOC enabled.
>>
>> Tested on ARM64 qemu with cmdline "percpu_alloc=page" based on 
>> v5.14-rc5.
>>
>> v3:
>> - search for a range that fits instead of always picking the end from
>>    vmalloc area suggested by Catalin.
>> - use NUMA_NO_NODE to avoid "virt_to_phys used for non-linear address:"
>>    issue in arm64 kasan_populate_early_vm_area_shadow().
>> - add Acked-by: Marco Elver <elver@google.com> to patch v3
>>
>> V2:
>> - fix build error when CONFIG_KASAN disabled, found by lkp@intel.com
>> - drop wrong __weak comment from kasan_populate_early_vm_area_shadow(),
>>    found by Marco Elver <elver@google.com>
>>
>> Kefeng Wang (3):
>>    vmalloc: Choose a better start address in vm_area_register_early()
>>    arm64: Support page mapping percpu first chunk allocator
>>    kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC
>>
>>   arch/arm64/Kconfig         |  4 ++
>>   arch/arm64/mm/kasan_init.c | 16 ++++++++
>>   drivers/base/arch_numa.c   | 82 +++++++++++++++++++++++++++++++++-----
>>   include/linux/kasan.h      |  6 +++
>>   mm/kasan/init.c            |  5 +++
>>   mm/vmalloc.c               | 17 +++++---
>>   6 files changed, 115 insertions(+), 15 deletions(-)
>>

Re: [PATCH v3 1/3] vmalloc: Choose a better start address in vm_area_register_early()

[Catalin Marinas]

On Mon, Aug 09, 2021 at 05:37:48PM +0800, Kefeng Wang wrote:
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index d5cd52805149..1e8fe08725b8 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2238,11 +2238,17 @@ void __init vm_area_add_early(struct vm_struct *vm)
>   */
>  void __init vm_area_register_early(struct vm_struct *vm, size_t align)
>  {
> -	static size_t vm_init_off __initdata;
> -	unsigned long addr;
> -
> -	addr = ALIGN(VMALLOC_START + vm_init_off, align);
> -	vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
> +	struct vm_struct *head = vmlist, *curr, *next;
> +	unsigned long addr = ALIGN(VMALLOC_START, align);
> +
> +	while (head != NULL) {

Nitpick: I'd use the same pattern as in vm_area_add_early(), i.e. a
'for' loop. You might as well insert it directly than calling the add
function and going through the loop again. Not a strong preference
either way.

> +		next = head->next;
> +		curr = head;
> +		head = next;
> +		addr = ALIGN((unsigned long)curr->addr + curr->size, align);
> +		if (next && (unsigned long)next->addr - addr > vm->size)

Is greater or equal sufficient?

> +			break;
> +	}
>  
>  	vm->addr = (void *)addr;

Another nitpick: it's very unlikely on a 64-bit architecture but not
impossible on 32-bit to hit VMALLOC_END here. Maybe some BUG_ON.

-- 
Catalin

Re: [PATCH v3 2/3] arm64: Support page mapping percpu first chunk allocator

[Catalin Marinas]

On Mon, Aug 09, 2021 at 05:37:49PM +0800, Kefeng Wang wrote:
> Percpu embedded first chunk allocator is the firstly option, but it
> could fails on ARM64, eg,
>   "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000"
>   "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000"
>   "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000"
> 
> then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838",
> even the system could not boot successfully.
> 
> Let's implement page mapping percpu first chunk allocator as a fallback
> to the embedding allocator to increase the robustness of the system.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Re: [PATCH v3 0/3] arm64: support page mapping percpu first chunk allocator

[Catalin Marinas]

On Thu, Aug 12, 2021 at 02:07:36PM +0800, Kefeng Wang wrote:
> The drivers/base/arch_numa.c is only shared by riscv and arm64,
> 
> and the change from patch2 won't broke riscv.
> 
> Could all patches be merged by arm64 tree? or any new comments?

The series touches drivers/ and mm/ but missing acks from both Greg and
Andrew (cc'ing them).

I'm also happy for the series to go in via the mm tree in case Andrew
wants to take it.

-- 
Catalin

Re: [PATCH v3 1/3] vmalloc: Choose a better start address in vm_area_register_early()

[Kefeng Wang]

On 2021/8/26 1:59, Catalin Marinas wrote:
> On Mon, Aug 09, 2021 at 05:37:48PM +0800, Kefeng Wang wrote:
>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
>> index d5cd52805149..1e8fe08725b8 100644
>> --- a/mm/vmalloc.c
>> +++ b/mm/vmalloc.c
>> @@ -2238,11 +2238,17 @@ void __init vm_area_add_early(struct vm_struct *vm)
>>    */
>>   void __init vm_area_register_early(struct vm_struct *vm, size_t align)
>>   {
>> -	static size_t vm_init_off __initdata;
>> -	unsigned long addr;
>> -
>> -	addr = ALIGN(VMALLOC_START + vm_init_off, align);
>> -	vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
>> +	struct vm_struct *head = vmlist, *curr, *next;
>> +	unsigned long addr = ALIGN(VMALLOC_START, align);
>> +
>> +	while (head != NULL) {
> Nitpick: I'd use the same pattern as in vm_area_add_early(), i.e. a
> 'for' loop. You might as well insert it directly than calling the add
> function and going through the loop again. Not a strong preference
> either way.
>
>> +		next = head->next;
>> +		curr = head;
>> +		head = next;
>> +		addr = ALIGN((unsigned long)curr->addr + curr->size, align);
>> +		if (next && (unsigned long)next->addr - addr > vm->size)
> Is greater or equal sufficient?
>
>> +			break;
>> +	}
>>   
>>   	vm->addr = (void *)addr;
> Another nitpick: it's very unlikely on a 64-bit architecture but not
> impossible on 32-bit to hit VMALLOC_END here. Maybe some BUG_ON.

Hi Catalin, thank for your review, I will update in the next version,

Could you take a look the following change, is it OK?

void __init vm_area_register_early(struct vm_struct *vm, size_t align)

{

          struct vm_struct *next, *cur, **p;
          unsigned long addr = ALIGN(VMALLOC_START, align);
BUG_ON(vmap_initialized);

          for (p = &vmlist; (cur = *p) != NULL, next = cur->next; p = 
&next) {
                  addr = ALIGN((unsigned long)cur->addr + cur->size, 
align);
                  if (next && (unsigned long)next->addr - addr >= 
vm->size) {
                          p = &next;
break;
}
}

          BUG_ON(addr > VMALLOC_END - vm->size);
          vm->addr = (void *)addr;
          vm->next = *p;
          *p = vm;
}


>