Re: [Xen-devel] [RFC PATCH 1/3] x86/xen: add basic KASAN support for PV kernel

2019-12-20 Thread Jürgen Groß 

On 19.12.19 17:42, Sergey Dyasli wrote:

On 18/12/2019 09:24, Jürgen Groß wrote:

On 17.12.19 15:08, Sergey Dyasli wrote:

This enables to use Outline instrumentation for Xen PV kernels.

KASAN_INLINE and KASAN_VMALLOC options currently lead to boot crashes
and hence disabled.

Rough edges in the patch are marked with XXX.

Signed-off-by: Sergey Dyasli 
---
   arch/x86/mm/init.c  | 14 ++
   arch/x86/mm/kasan_init_64.c | 28 
   arch/x86/xen/Makefile   |  7 +++
   arch/x86/xen/enlighten_pv.c |  3 +++
   arch/x86/xen/mmu_pv.c   | 13 +++--
   arch/x86/xen/multicalls.c   | 10 ++
   drivers/xen/Makefile|  2 ++
   kernel/Makefile |  2 ++
   lib/Kconfig.kasan   |  3 ++-
   9 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index e7bb483557c9..0c98a45eec6c 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -8,6 +8,8 @@
   #include 
   #include 
   +#include 
+
   #include 
   #include 
   #include 
@@ -835,6 +837,18 @@ void free_kernel_image_pages(const char *what, void 
*begin, void *end)
   unsigned long end_ul = (unsigned long)end;
   unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
   +/*
+ * XXX: skip this for now. Otherwise it leads to:
+ *
+ * (XEN) mm.c:2713:d157v0 Bad type (saw 8c01 != exp 
e000) for mfn 36f40 (pfn 02f40)
+ * (XEN) mm.c:1043:d157v0 Could not get page type PGT_writable_page
+ * (XEN) mm.c:1096:d157v0 Error getting mfn 36f40 (pfn 02f40) from L1 
entry 801036f40067 for l1e_owner d157, pg_owner d157
+ *
+ * and further #PF error: [PROT] [WRITE] in the kernel.
+ */
+if (xen_pv_domain() && IS_ENABLED(CONFIG_KASAN))
+return;
+


I guess this is related to freeing some kasan page tables without
unpinning them?


Your guess was correct. Turned out that early_top_pgt which I pinned and made RO
is located in .init section and that was causing issues. Unpinning it and making
RW again right after kasan_init() switches to use init_top_pgt seem to fix this
issue.




   free_init_pages(what, begin_ul, end_ul);
 /*
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index cf5bc37c90ac..caee2022f8b0 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -13,6 +13,8 @@
   #include 
   #include 
   +#include 
+
   #include 
   #include 
   #include 
@@ -20,6 +22,9 @@
   #include 
   #include 
   +#include 
+#include 
+
   extern struct range pfn_mapped[E820_MAX_ENTRIES];
 static p4d_t tmp_p4d_table[MAX_PTRS_PER_P4D] __initdata 
__aligned(PAGE_SIZE);
@@ -305,6 +310,12 @@ static struct notifier_block kasan_die_notifier = {
   };
   #endif
   +#ifdef CONFIG_XEN
+/* XXX: this should go to some header */
+void __init set_page_prot(void *addr, pgprot_t prot);
+void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn);
+#endif
+


Instead of exporting those, why don't you ...


   void __init kasan_early_init(void)
   {
   int i;
@@ -332,6 +343,16 @@ void __init kasan_early_init(void)
   for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++)
   kasan_early_shadow_p4d[i] = __p4d(p4d_val);
   +if (xen_pv_domain()) {
+/* PV page tables must have PAGE_KERNEL_RO */
+set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
+set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
+set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);


add a function doing that to mmu_pv.c (e.g. xen_pv_kasan_early_init())?


Sounds like a good suggestion, but new functions still need some header for
declarations (xen/xen.h?). And kasan_map_early_shadow() will need exporting


xen/xen-ops.h


through kasan.h as well, but that's probably not an issue.


You could let the new function return (pgd_t *)xen_start_info->pt_base
and use that here, e.g.:

if (xen_pv_domain()) {
pgd_t *pgd;

pgd = xen_kasan_early_init();
kasan_map_early_shadow(pgd);
}






+
+/* Add mappings to the initial PV page tables */
+kasan_map_early_shadow((pgd_t *)xen_start_info->pt_base);
+}
+
   kasan_map_early_shadow(early_top_pgt);
   kasan_map_early_shadow(init_top_pgt);
   }
@@ -369,6 +390,13 @@ void __init kasan_init(void)
   __pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE));
   }
   +if (xen_pv_domain()) {
+/* PV page tables must be pinned */
+set_page_prot(early_top_pgt, PAGE_KERNEL_RO);
+pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
+  PFN_DOWN(__pa_symbol(early_top_pgt)));


and another one like xen_pv_kasan_init() here.


Now there needs to be a 3rd function to unpin early_top_pgt.


Not if you do the load_cr3 in the xen pv case in the new function:

if (xen_pv_domain())
xen_kasan_load_cr3(early_top_pgt);
else
load_cr3(early_top_pgt);






+}
+
   load_cr3(early_top_pgt);

Re: [Xen-devel] [RFC PATCH 1/3] x86/xen: add basic KASAN support for PV kernel

2019-12-19 Thread Sergey Dyasli 
On 18/12/2019 09:24, Jürgen Groß wrote:
> On 17.12.19 15:08, Sergey Dyasli wrote:
>> This enables to use Outline instrumentation for Xen PV kernels.
>>
>> KASAN_INLINE and KASAN_VMALLOC options currently lead to boot crashes
>> and hence disabled.
>>
>> Rough edges in the patch are marked with XXX.
>>
>> Signed-off-by: Sergey Dyasli 
>> ---
>>   arch/x86/mm/init.c  | 14 ++
>>   arch/x86/mm/kasan_init_64.c | 28 
>>   arch/x86/xen/Makefile   |  7 +++
>>   arch/x86/xen/enlighten_pv.c |  3 +++
>>   arch/x86/xen/mmu_pv.c   | 13 +++--
>>   arch/x86/xen/multicalls.c   | 10 ++
>>   drivers/xen/Makefile|  2 ++
>>   kernel/Makefile |  2 ++
>>   lib/Kconfig.kasan   |  3 ++-
>>   9 files changed, 79 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
>> index e7bb483557c9..0c98a45eec6c 100644
>> --- a/arch/x86/mm/init.c
>> +++ b/arch/x86/mm/init.c
>> @@ -8,6 +8,8 @@
>>   #include 
>>   #include 
>>   +#include 
>> +
>>   #include 
>>   #include 
>>   #include 
>> @@ -835,6 +837,18 @@ void free_kernel_image_pages(const char *what, void 
>> *begin, void *end)
>>   unsigned long end_ul = (unsigned long)end;
>>   unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
>>   +/*
>> + * XXX: skip this for now. Otherwise it leads to:
>> + *
>> + * (XEN) mm.c:2713:d157v0 Bad type (saw 8c01 != exp 
>> e000) for mfn 36f40 (pfn 02f40)
>> + * (XEN) mm.c:1043:d157v0 Could not get page type PGT_writable_page
>> + * (XEN) mm.c:1096:d157v0 Error getting mfn 36f40 (pfn 02f40) from L1 
>> entry 801036f40067 for l1e_owner d157, pg_owner d157
>> + *
>> + * and further #PF error: [PROT] [WRITE] in the kernel.
>> + */
>> +if (xen_pv_domain() && IS_ENABLED(CONFIG_KASAN))
>> +return;
>> +
> 
> I guess this is related to freeing some kasan page tables without
> unpinning them?

Your guess was correct. Turned out that early_top_pgt which I pinned and made RO
is located in .init section and that was causing issues. Unpinning it and making
RW again right after kasan_init() switches to use init_top_pgt seem to fix this
issue.

> 
>>   free_init_pages(what, begin_ul, end_ul);
>> /*
>> diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
>> index cf5bc37c90ac..caee2022f8b0 100644
>> --- a/arch/x86/mm/kasan_init_64.c
>> +++ b/arch/x86/mm/kasan_init_64.c
>> @@ -13,6 +13,8 @@
>>   #include 
>>   #include 
>>   +#include 
>> +
>>   #include 
>>   #include 
>>   #include 
>> @@ -20,6 +22,9 @@
>>   #include 
>>   #include 
>>   +#include 
>> +#include 
>> +
>>   extern struct range pfn_mapped[E820_MAX_ENTRIES];
>> static p4d_t tmp_p4d_table[MAX_PTRS_PER_P4D] __initdata 
>> __aligned(PAGE_SIZE);
>> @@ -305,6 +310,12 @@ static struct notifier_block kasan_die_notifier = {
>>   };
>>   #endif
>>   +#ifdef CONFIG_XEN
>> +/* XXX: this should go to some header */
>> +void __init set_page_prot(void *addr, pgprot_t prot);
>> +void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn);
>> +#endif
>> +
> 
> Instead of exporting those, why don't you ...
> 
>>   void __init kasan_early_init(void)
>>   {
>>   int i;
>> @@ -332,6 +343,16 @@ void __init kasan_early_init(void)
>>   for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++)
>>   kasan_early_shadow_p4d[i] = __p4d(p4d_val);
>>   +if (xen_pv_domain()) {
>> +/* PV page tables must have PAGE_KERNEL_RO */
>> +set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
>> +set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
>> +set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);
> 
> add a function doing that to mmu_pv.c (e.g. xen_pv_kasan_early_init())?

Sounds like a good suggestion, but new functions still need some header for
declarations (xen/xen.h?). And kasan_map_early_shadow() will need exporting
through kasan.h as well, but that's probably not an issue.

> 
>> +
>> +/* Add mappings to the initial PV page tables */
>> +kasan_map_early_shadow((pgd_t *)xen_start_info->pt_base);
>> +}
>> +
>>   kasan_map_early_shadow(early_top_pgt);
>>   kasan_map_early_shadow(init_top_pgt);
>>   }
>> @@ -369,6 +390,13 @@ void __init kasan_init(void)
>>   __pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE));
>>   }
>>   +if (xen_pv_domain()) {
>> +/* PV page tables must be pinned */
>> +set_page_prot(early_top_pgt, PAGE_KERNEL_RO);
>> +pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
>> +  PFN_DOWN(__pa_symbol(early_top_pgt)));
> 
> and another one like xen_pv_kasan_init() here.

Now there needs to be a 3rd function to unpin early_top_pgt.

> 
>> +}
>> +
>>   load_cr3(early_top_pgt);
>>   __flush_tlb_all();
>>   diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
>> index 084de77a109e..102fad0b0bca 100644
>> ---

Re: [Xen-devel] [RFC PATCH 1/3] x86/xen: add basic KASAN support for PV kernel

2019-12-18 Thread Jürgen Groß 

On 17.12.19 15:08, Sergey Dyasli wrote:

This enables to use Outline instrumentation for Xen PV kernels.

KASAN_INLINE and KASAN_VMALLOC options currently lead to boot crashes
and hence disabled.

Rough edges in the patch are marked with XXX.

Signed-off-by: Sergey Dyasli 
---
  arch/x86/mm/init.c  | 14 ++
  arch/x86/mm/kasan_init_64.c | 28 
  arch/x86/xen/Makefile   |  7 +++
  arch/x86/xen/enlighten_pv.c |  3 +++
  arch/x86/xen/mmu_pv.c   | 13 +++--
  arch/x86/xen/multicalls.c   | 10 ++
  drivers/xen/Makefile|  2 ++
  kernel/Makefile |  2 ++
  lib/Kconfig.kasan   |  3 ++-
  9 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index e7bb483557c9..0c98a45eec6c 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -8,6 +8,8 @@
  #include 
  #include 
  
+#include 

+
  #include 
  #include 
  #include 
@@ -835,6 +837,18 @@ void free_kernel_image_pages(const char *what, void 
*begin, void *end)
unsigned long end_ul = (unsigned long)end;
unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
  
+	/*

+* XXX: skip this for now. Otherwise it leads to:
+*
+* (XEN) mm.c:2713:d157v0 Bad type (saw 8c01 != exp 
e000) for mfn 36f40 (pfn 02f40)
+* (XEN) mm.c:1043:d157v0 Could not get page type PGT_writable_page
+* (XEN) mm.c:1096:d157v0 Error getting mfn 36f40 (pfn 02f40) from L1 
entry 801036f40067 for l1e_owner d157, pg_owner d157
+*
+* and further #PF error: [PROT] [WRITE] in the kernel.
+*/
+   if (xen_pv_domain() && IS_ENABLED(CONFIG_KASAN))
+   return;
+


I guess this is related to freeing some kasan page tables without
unpinning them?


free_init_pages(what, begin_ul, end_ul);
  
  	/*

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index cf5bc37c90ac..caee2022f8b0 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -13,6 +13,8 @@
  #include 
  #include 
  
+#include 

+
  #include 
  #include 
  #include 
@@ -20,6 +22,9 @@
  #include 
  #include 
  
+#include 

+#include 
+
  extern struct range pfn_mapped[E820_MAX_ENTRIES];
  
  static p4d_t tmp_p4d_table[MAX_PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);

@@ -305,6 +310,12 @@ static struct notifier_block kasan_die_notifier = {
  };
  #endif
  
+#ifdef CONFIG_XEN

+/* XXX: this should go to some header */
+void __init set_page_prot(void *addr, pgprot_t prot);
+void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn);
+#endif
+


Instead of exporting those, why don't you ...


  void __init kasan_early_init(void)
  {
int i;
@@ -332,6 +343,16 @@ void __init kasan_early_init(void)
for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++)
kasan_early_shadow_p4d[i] = __p4d(p4d_val);
  
+	if (xen_pv_domain()) {

+   /* PV page tables must have PAGE_KERNEL_RO */
+   set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
+   set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
+   set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);


add a function doing that to mmu_pv.c (e.g. xen_pv_kasan_early_init())?


+
+   /* Add mappings to the initial PV page tables */
+   kasan_map_early_shadow((pgd_t *)xen_start_info->pt_base);
+   }
+
kasan_map_early_shadow(early_top_pgt);
kasan_map_early_shadow(init_top_pgt);
  }
@@ -369,6 +390,13 @@ void __init kasan_init(void)
__pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE));
}
  
+	if (xen_pv_domain()) {

+   /* PV page tables must be pinned */
+   set_page_prot(early_top_pgt, PAGE_KERNEL_RO);
+   pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa_symbol(early_top_pgt)));


and another one like xen_pv_kasan_init() here.


+   }
+
load_cr3(early_top_pgt);
__flush_tlb_all();
  
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile

index 084de77a109e..102fad0b0bca 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -1,3 +1,10 @@
+KASAN_SANITIZE_enlighten_pv.o := n
+KASAN_SANITIZE_enlighten.o := n
+KASAN_SANITIZE_irq.o := n
+KASAN_SANITIZE_mmu_pv.o := n
+KASAN_SANITIZE_p2m.o := n
+KASAN_SANITIZE_multicalls.o := n
+
  # SPDX-License-Identifier: GPL-2.0
  OBJECT_FILES_NON_STANDARD_xen-asm_$(BITS).o := y
  
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c

index ae4a41ca19f6..27de55699f24 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -72,6 +72,7 @@
  #include 
  #include 
  #include 
+#include 
  
  #ifdef CONFIG_ACPI

  #include 
@@ -1231,6 +1232,8 @@ asmlinkage __visible void __init xen_start_kernel(void)
/* Get mfn list */

[Xen-devel] [RFC PATCH 1/3] x86/xen: add basic KASAN support for PV kernel

2019-12-17 Thread Sergey Dyasli 
This enables to use Outline instrumentation for Xen PV kernels.

KASAN_INLINE and KASAN_VMALLOC options currently lead to boot crashes
and hence disabled.

Rough edges in the patch are marked with XXX.

Signed-off-by: Sergey Dyasli 
---
 arch/x86/mm/init.c  | 14 ++
 arch/x86/mm/kasan_init_64.c | 28 
 arch/x86/xen/Makefile   |  7 +++
 arch/x86/xen/enlighten_pv.c |  3 +++
 arch/x86/xen/mmu_pv.c   | 13 +++--
 arch/x86/xen/multicalls.c   | 10 ++
 drivers/xen/Makefile|  2 ++
 kernel/Makefile |  2 ++
 lib/Kconfig.kasan   |  3 ++-
 9 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index e7bb483557c9..0c98a45eec6c 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -8,6 +8,8 @@
 #include 
 #include 
 
+#include 
+
 #include 
 #include 
 #include 
@@ -835,6 +837,18 @@ void free_kernel_image_pages(const char *what, void 
*begin, void *end)
unsigned long end_ul = (unsigned long)end;
unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
 
+   /*
+* XXX: skip this for now. Otherwise it leads to:
+*
+* (XEN) mm.c:2713:d157v0 Bad type (saw 8c01 != exp 
e000) for mfn 36f40 (pfn 02f40)
+* (XEN) mm.c:1043:d157v0 Could not get page type PGT_writable_page
+* (XEN) mm.c:1096:d157v0 Error getting mfn 36f40 (pfn 02f40) from L1 
entry 801036f40067 for l1e_owner d157, pg_owner d157
+*
+* and further #PF error: [PROT] [WRITE] in the kernel.
+*/
+   if (xen_pv_domain() && IS_ENABLED(CONFIG_KASAN))
+   return;
+
free_init_pages(what, begin_ul, end_ul);
 
/*
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index cf5bc37c90ac..caee2022f8b0 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -13,6 +13,8 @@
 #include 
 #include 
 
+#include 
+
 #include 
 #include 
 #include 
@@ -20,6 +22,9 @@
 #include 
 #include 
 
+#include 
+#include 
+
 extern struct range pfn_mapped[E820_MAX_ENTRIES];
 
 static p4d_t tmp_p4d_table[MAX_PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);
@@ -305,6 +310,12 @@ static struct notifier_block kasan_die_notifier = {
 };
 #endif
 
+#ifdef CONFIG_XEN
+/* XXX: this should go to some header */
+void __init set_page_prot(void *addr, pgprot_t prot);
+void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn);
+#endif
+
 void __init kasan_early_init(void)
 {
int i;
@@ -332,6 +343,16 @@ void __init kasan_early_init(void)
for (i = 0; pgtable_l5_enabled() && i < PTRS_PER_P4D; i++)
kasan_early_shadow_p4d[i] = __p4d(p4d_val);
 
+   if (xen_pv_domain()) {
+   /* PV page tables must have PAGE_KERNEL_RO */
+   set_page_prot(kasan_early_shadow_pud, PAGE_KERNEL_RO);
+   set_page_prot(kasan_early_shadow_pmd, PAGE_KERNEL_RO);
+   set_page_prot(kasan_early_shadow_pte, PAGE_KERNEL_RO);
+
+   /* Add mappings to the initial PV page tables */
+   kasan_map_early_shadow((pgd_t *)xen_start_info->pt_base);
+   }
+
kasan_map_early_shadow(early_top_pgt);
kasan_map_early_shadow(init_top_pgt);
 }
@@ -369,6 +390,13 @@ void __init kasan_init(void)
__pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE));
}
 
+   if (xen_pv_domain()) {
+   /* PV page tables must be pinned */
+   set_page_prot(early_top_pgt, PAGE_KERNEL_RO);
+   pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa_symbol(early_top_pgt)));
+   }
+
load_cr3(early_top_pgt);
__flush_tlb_all();
 
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 084de77a109e..102fad0b0bca 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -1,3 +1,10 @@
+KASAN_SANITIZE_enlighten_pv.o := n
+KASAN_SANITIZE_enlighten.o := n
+KASAN_SANITIZE_irq.o := n
+KASAN_SANITIZE_mmu_pv.o := n
+KASAN_SANITIZE_p2m.o := n
+KASAN_SANITIZE_multicalls.o := n
+
 # SPDX-License-Identifier: GPL-2.0
 OBJECT_FILES_NON_STANDARD_xen-asm_$(BITS).o := y
 
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index ae4a41ca19f6..27de55699f24 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -72,6 +72,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #ifdef CONFIG_ACPI
 #include 
@@ -1231,6 +1232,8 @@ asmlinkage __visible void __init xen_start_kernel(void)
/* Get mfn list */
xen_build_dynamic_phys_to_machine();
 
+   kasan_early_init();
+
/*
 * Set up kernel GDT and segment registers, mainly so that
 * -fstack-protector code can be executed.
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index c8dbee62ec2a..eaf63f1f26af 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -1079,7