Re: [Xen-devel] [PATCH v1 1/4] kasan: introduce set_pmd_early_shadow()
On 15.01.20 17:32, Sergey Dyasli wrote:
On 15/01/2020 11:09, Jürgen Groß wrote:
On 15.01.20 11:54, Sergey Dyasli wrote:
Hi Juergen,
On 08/01/2020 15:20, Sergey Dyasli wrote:
It is incorrect to call pmd_populate_kernel() multiple times for the
same page table. Xen notices it during kasan_populate_early_shadow():
(XEN) mm.c:3222:d155v0 mfn 3704b already pinned
This happens for kasan_early_shadow_pte when USE_SPLIT_PTE_PTLOCKS is
enabled. Fix this by introducing set_pmd_early_shadow() which calls
pmd_populate_kernel() only once and uses set_pmd() afterwards.
Signed-off-by: Sergey Dyasli
Looks like the plan to use set_pmd() directly has failed: it's an
arch-specific function and can't be used in arch-independent code
(as kbuild test robot has proven).
Do you see any way out of this other than disabling SPLIT_PTE_PTLOCKS
for PV KASAN?
Change set_pmd_early_shadow() like the following:
#ifdef CONFIG_XEN_PV
static inline void set_pmd_early_shadow(pmd_t *pmd, pte_t *early_shadow)
{
static bool pmd_populated = false;
if (likely(pmd_populated)) {
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
} else {
pmd_populate_kernel(_mm, pmd, early_shadow);
pmd_populated = true;
}
}
#else
static inline void set_pmd_early_shadow(pmd_t *pmd, pte_t *early_shadow)
{
pmd_populate_kernel(_mm, pmd, early_shadow);
}
#endif
... and move it to include/xen/xen-ops.h and call it with
lm_alias(kasan_early_shadow_pte) as the second parameter.
Your suggestion to use ifdef is really good, especially now when I
figured out that CONFIG_XEN_PV implies X86. But I don't like the idea
of kasan code calling a non-empty function from xen-ops.h when
CONFIG_XEN_PV is not defined. I'd prefer to keep set_pmd_early_shadow()
in mm/kasan/init.c with the suggested ifdef.
Fine with me.
Juergen
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Re: [Xen-devel] [PATCH v1 1/4] kasan: introduce set_pmd_early_shadow()
On 15/01/2020 11:09, Jürgen Groß wrote:
> On 15.01.20 11:54, Sergey Dyasli wrote:
>> Hi Juergen,
>>
>> On 08/01/2020 15:20, Sergey Dyasli wrote:
>>> It is incorrect to call pmd_populate_kernel() multiple times for the
>>> same page table. Xen notices it during kasan_populate_early_shadow():
>>>
>>> (XEN) mm.c:3222:d155v0 mfn 3704b already pinned
>>>
>>> This happens for kasan_early_shadow_pte when USE_SPLIT_PTE_PTLOCKS is
>>> enabled. Fix this by introducing set_pmd_early_shadow() which calls
>>> pmd_populate_kernel() only once and uses set_pmd() afterwards.
>>>
>>> Signed-off-by: Sergey Dyasli
>>
>> Looks like the plan to use set_pmd() directly has failed: it's an
>> arch-specific function and can't be used in arch-independent code
>> (as kbuild test robot has proven).
>>
>> Do you see any way out of this other than disabling SPLIT_PTE_PTLOCKS
>> for PV KASAN?
>
> Change set_pmd_early_shadow() like the following:
>
> #ifdef CONFIG_XEN_PV
> static inline void set_pmd_early_shadow(pmd_t *pmd, pte_t *early_shadow)
> {
> static bool pmd_populated = false;
>
> if (likely(pmd_populated)) {
> set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
> } else {
> pmd_populate_kernel(_mm, pmd, early_shadow);
> pmd_populated = true;
> }
> }
> #else
> static inline void set_pmd_early_shadow(pmd_t *pmd, pte_t *early_shadow)
> {
> pmd_populate_kernel(_mm, pmd, early_shadow);
> }
> #endif
>
> ... and move it to include/xen/xen-ops.h and call it with
> lm_alias(kasan_early_shadow_pte) as the second parameter.
Your suggestion to use ifdef is really good, especially now when I
figured out that CONFIG_XEN_PV implies X86. But I don't like the idea
of kasan code calling a non-empty function from xen-ops.h when
CONFIG_XEN_PV is not defined. I'd prefer to keep set_pmd_early_shadow()
in mm/kasan/init.c with the suggested ifdef.
--
Thanks,
Sergey
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Re: [Xen-devel] [PATCH v1 1/4] kasan: introduce set_pmd_early_shadow()
On 15.01.20 11:54, Sergey Dyasli wrote:
Hi Juergen,
On 08/01/2020 15:20, Sergey Dyasli wrote:
It is incorrect to call pmd_populate_kernel() multiple times for the
same page table. Xen notices it during kasan_populate_early_shadow():
(XEN) mm.c:3222:d155v0 mfn 3704b already pinned
This happens for kasan_early_shadow_pte when USE_SPLIT_PTE_PTLOCKS is
enabled. Fix this by introducing set_pmd_early_shadow() which calls
pmd_populate_kernel() only once and uses set_pmd() afterwards.
Signed-off-by: Sergey Dyasli
Looks like the plan to use set_pmd() directly has failed: it's an
arch-specific function and can't be used in arch-independent code
(as kbuild test robot has proven).
Do you see any way out of this other than disabling SPLIT_PTE_PTLOCKS
for PV KASAN?
Change set_pmd_early_shadow() like the following:
#ifdef CONFIG_XEN_PV
static inline void set_pmd_early_shadow(pmd_t *pmd, pte_t *early_shadow)
{
static bool pmd_populated = false;
if (likely(pmd_populated)) {
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
} else {
pmd_populate_kernel(_mm, pmd, early_shadow);
pmd_populated = true;
}
}
#else
static inline void set_pmd_early_shadow(pmd_t *pmd, pte_t *early_shadow)
{
pmd_populate_kernel(_mm, pmd, early_shadow);
}
#endif
... and move it to include/xen/xen-ops.h and call it with
lm_alias(kasan_early_shadow_pte) as the second parameter.
Juergen
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Re: [Xen-devel] [PATCH v1 1/4] kasan: introduce set_pmd_early_shadow()
Hi Juergen, On 08/01/2020 15:20, Sergey Dyasli wrote: > It is incorrect to call pmd_populate_kernel() multiple times for the > same page table. Xen notices it during kasan_populate_early_shadow(): > > (XEN) mm.c:3222:d155v0 mfn 3704b already pinned > > This happens for kasan_early_shadow_pte when USE_SPLIT_PTE_PTLOCKS is > enabled. Fix this by introducing set_pmd_early_shadow() which calls > pmd_populate_kernel() only once and uses set_pmd() afterwards. > > Signed-off-by: Sergey Dyasli Looks like the plan to use set_pmd() directly has failed: it's an arch-specific function and can't be used in arch-independent code (as kbuild test robot has proven). Do you see any way out of this other than disabling SPLIT_PTE_PTLOCKS for PV KASAN? -- Thanks, Sergey ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] [PATCH v1 1/4] kasan: introduce set_pmd_early_shadow()
Hi Sergey,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on net-next/master]
[also build test ERROR on net/master linus/master v5.5-rc5 next-20200109]
[cannot apply to xen-tip/linux-next]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url:
https://github.com/0day-ci/linux/commits/Sergey-Dyasli/basic-KASAN-support-for-Xen-PV-domains/20200110-042623
base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git
4a4a52d49d11f5c4a0df8b9806c8c5563801f753
config: s390-allmodconfig (attached as .config)
compiler: s390-linux-gcc (GCC) 7.5.0
reproduce:
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.5.0 make.cross ARCH=s390
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot
All errors (new ones prefixed by >>):
mm//kasan/init.c: In function 'set_pmd_early_shadow':
>> mm//kasan/init.c:90:3: error: implicit declaration of function 'set_pmd';
>> did you mean 'get_pid'? [-Werror=implicit-function-declaration]
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^~~
get_pid
In file included from arch/s390/include/asm/thread_info.h:26:0,
from include/linux/thread_info.h:38,
from arch/s390/include/asm/preempt.h:6,
from include/linux/preempt.h:78,
from include/linux/spinlock.h:51,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:6,
from include/linux/mm.h:10,
from include/linux/memblock.h:13,
from mm//kasan/init.c:14:
mm//kasan/init.c:90:43: error: '_PAGE_TABLE' undeclared (first use in this
function); did you mean 'NR_PAGETABLE'?
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
arch/s390/include/asm/page.h:96:37: note: in definition of macro '__pmd'
#define __pmd(x)((pmd_t) { (x) } )
^
mm//kasan/init.c:90:43: note: each undeclared identifier is reported only
once for each function it appears in
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
arch/s390/include/asm/page.h:96:37: note: in definition of macro '__pmd'
#define __pmd(x)((pmd_t) { (x) } )
^
cc1: some warnings being treated as errors
vim +90 mm//kasan/init.c
83
84 static inline void set_pmd_early_shadow(pmd_t *pmd)
85 {
86 static bool pmd_populated = false;
87 pte_t *early_shadow = lm_alias(kasan_early_shadow_pte);
88
89 if (likely(pmd_populated)) {
> 90 set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
91 } else {
92 pmd_populate_kernel(_mm, pmd, early_shadow);
93 pmd_populated = true;
94 }
95 }
96
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org Intel Corporation
.config.gz
Description: application/gzip
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Re: [Xen-devel] [PATCH v1 1/4] kasan: introduce set_pmd_early_shadow()
Hi Sergey,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on net-next/master]
[also build test ERROR on net/master linus/master v5.5-rc5 next-20200109]
[cannot apply to xen-tip/linux-next]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url:
https://github.com/0day-ci/linux/commits/Sergey-Dyasli/basic-KASAN-support-for-Xen-PV-domains/20200110-042623
base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git
4a4a52d49d11f5c4a0df8b9806c8c5563801f753
config: arm64-randconfig-a001-20200109 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 7.5.0
reproduce:
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.5.0 make.cross ARCH=arm64
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot
All error/warnings (new ones prefixed by >>):
In file included from arch/arm64/include/asm/kasan.h:9:0,
from arch/arm64/include/asm/processor.h:34,
from include/asm-generic/qrwlock.h:14,
from ./arch/arm64/include/generated/asm/qrwlock.h:1,
from arch/arm64/include/asm/spinlock.h:8,
from include/linux/spinlock.h:89,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:6,
from include/linux/mm.h:10,
from include/linux/memblock.h:13,
from mm/kasan/init.c:14:
mm/kasan/init.c: In function 'set_pmd_early_shadow':
>> mm/kasan/init.c:90:43: error: '_PAGE_TABLE' undeclared (first use in this
>> function); did you mean 'NR_PAGETABLE'?
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
arch/arm64/include/asm/pgtable-types.h:40:30: note: in definition of macro
'__pgd'
#define __pgd(x) ((pgd_t) { (x) } )
^
>> include/asm-generic/pgtable-nopmd.h:50:32: note: in expansion of macro
>> '__pud'
#define __pmd(x)((pmd_t) { __pud(x) } )
^
>> mm/kasan/init.c:90:16: note: in expansion of macro '__pmd'
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
mm/kasan/init.c:90:43: note: each undeclared identifier is reported only
once for each function it appears in
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
arch/arm64/include/asm/pgtable-types.h:40:30: note: in definition of macro
'__pgd'
#define __pgd(x) ((pgd_t) { (x) } )
^
>> include/asm-generic/pgtable-nopmd.h:50:32: note: in expansion of macro
>> '__pud'
#define __pmd(x)((pmd_t) { __pud(x) } )
^
>> mm/kasan/init.c:90:16: note: in expansion of macro '__pmd'
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
--
In file included from arch/arm64/include/asm/kasan.h:9:0,
from arch/arm64/include/asm/processor.h:34,
from include/asm-generic/qrwlock.h:14,
from ./arch/arm64/include/generated/asm/qrwlock.h:1,
from arch/arm64/include/asm/spinlock.h:8,
from include/linux/spinlock.h:89,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:6,
from include/linux/mm.h:10,
from include/linux/memblock.h:13,
from mm//kasan/init.c:14:
mm//kasan/init.c: In function 'set_pmd_early_shadow':
mm//kasan/init.c:90:43: error: '_PAGE_TABLE' undeclared (first use in this
function); did you mean 'NR_PAGETABLE'?
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
arch/arm64/include/asm/pgtable-types.h:40:30: note: in definition of macro
'__pgd'
#define __pgd(x) ((pgd_t) { (x) } )
^
>> include/asm-generic/pgtable-nopmd.h:50:32: note: in expansion of macro
>> '__pud'
#define __pmd(x)((pmd_t) { __pud(x) } )
^
mm//kasan/init.c:90:16: note: in expansion of macro '__pmd'
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
mm//kasan/init.c:90:43: note: each undeclared identifier is reported only
once for each function it appears in
set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
^
arch/arm64/include/asm/pgtable-types.h:40:30: note: in definition of macro
'__pgd'
#define
[Xen-devel] [PATCH v1 1/4] kasan: introduce set_pmd_early_shadow()
It is incorrect to call pmd_populate_kernel() multiple times for the
same page table. Xen notices it during kasan_populate_early_shadow():
(XEN) mm.c:3222:d155v0 mfn 3704b already pinned
This happens for kasan_early_shadow_pte when USE_SPLIT_PTE_PTLOCKS is
enabled. Fix this by introducing set_pmd_early_shadow() which calls
pmd_populate_kernel() only once and uses set_pmd() afterwards.
Signed-off-by: Sergey Dyasli
---
RFC --> v1:
- New patch
---
mm/kasan/init.c | 25 +
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/mm/kasan/init.c b/mm/kasan/init.c
index ce45c491ebcd..a4077320777f 100644
--- a/mm/kasan/init.c
+++ b/mm/kasan/init.c
@@ -81,6 +81,19 @@ static inline bool kasan_early_shadow_page_entry(pte_t pte)
return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
}
+static inline void set_pmd_early_shadow(pmd_t *pmd)
+{
+ static bool pmd_populated = false;
+ pte_t *early_shadow = lm_alias(kasan_early_shadow_pte);
+
+ if (likely(pmd_populated)) {
+ set_pmd(pmd, __pmd(__pa(early_shadow) | _PAGE_TABLE));
+ } else {
+ pmd_populate_kernel(_mm, pmd, early_shadow);
+ pmd_populated = true;
+ }
+}
+
static __init void *early_alloc(size_t size, int node)
{
void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
@@ -120,8 +133,7 @@ static int __ref zero_pmd_populate(pud_t *pud, unsigned
long addr,
next = pmd_addr_end(addr, end);
if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
- pmd_populate_kernel(_mm, pmd,
- lm_alias(kasan_early_shadow_pte));
+ set_pmd_early_shadow(pmd);
continue;
}
@@ -157,8 +169,7 @@ static int __ref zero_pud_populate(p4d_t *p4d, unsigned
long addr,
pud_populate(_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
- pmd_populate_kernel(_mm, pmd,
- lm_alias(kasan_early_shadow_pte));
+ set_pmd_early_shadow(pmd);
continue;
}
@@ -198,8 +209,7 @@ static int __ref zero_p4d_populate(pgd_t *pgd, unsigned
long addr,
pud_populate(_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
- pmd_populate_kernel(_mm, pmd,
- lm_alias(kasan_early_shadow_pte));
+ set_pmd_early_shadow(pmd);
continue;
}
@@ -271,8 +281,7 @@ int __ref kasan_populate_early_shadow(const void
*shadow_start,
pud_populate(_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
- pmd_populate_kernel(_mm, pmd,
- lm_alias(kasan_early_shadow_pte));
+ set_pmd_early_shadow(pmd);
continue;
}
--
2.17.1
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