LinuxLists.cc - [PATCH v3] mm: make minimum slab alignment a runtime property

2022-04-22 23:00:55

Subject: [PATCH v3] mm: make minimum slab alignment a runtime property

When CONFIG_KASAN_HW_TAGS is enabled we currently increase the minimum
slab alignment to 16. This happens even if MTE is not supported in
hardware or disabled via kasan=off, which creates an unnecessary
memory overhead in those cases. Eliminate this overhead by making
the minimum slab alignment a runtime property and only aligning to
16 if KASAN is enabled at runtime.

On a DragonBoard 845c (non-MTE hardware) with a kernel built with
CONFIG_KASAN_HW_TAGS, waiting for quiescence after a full Android
boot I see the following Slab measurements in /proc/meminfo (median
of 3 reboots):

Before: 169020 kB
After: 167304 kB

Link: https://linux-review.googlesource.com/id/I752e725179b43b144153f4b6f584ceb646473ead
Signed-off-by: Peter Collingbourne <[email protected]>
Reviewed-by: Andrey Konovalov <[email protected]>
---
v3:
- go back to ARCH_SLAB_MINALIGN
- revert changes to fs/binfmt_flat.c
- update arch_slab_minalign() comment to say that it must be a power of two

v2:
- use max instead of max_t in flat_stack_align()

arch/arm64/include/asm/cache.h | 17 ++++++++++++-----
include/linux/slab.h | 12 ++++++++++++
mm/slab.c | 7 +++----
mm/slab_common.c | 3 +--
mm/slob.c | 6 +++---
5 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
index a074459f8f2f..22b22dc1b1b5 100644
--- a/arch/arm64/include/asm/cache.h
+++ b/arch/arm64/include/asm/cache.h
@@ -6,6 +6,7 @@
#define __ASM_CACHE_H

#include <asm/cputype.h>
+#include <asm/mte-def.h>

#define CTR_L1IP_SHIFT 14
#define CTR_L1IP_MASK 3
@@ -49,16 +50,22 @@
*/
#define ARCH_DMA_MINALIGN (128)

+#ifndef __ASSEMBLY__
+
+#include <linux/bitops.h>
+#include <linux/kasan-enabled.h>
+
#ifdef CONFIG_KASAN_SW_TAGS
#define ARCH_SLAB_MINALIGN (1ULL << KASAN_SHADOW_SCALE_SHIFT)
#elif defined(CONFIG_KASAN_HW_TAGS)
-#define ARCH_SLAB_MINALIGN MTE_GRANULE_SIZE
+static inline size_t arch_slab_minalign(void)
+{
+ return kasan_hw_tags_enabled() ? MTE_GRANULE_SIZE :
+ __alignof__(unsigned long long);
+}
+#define arch_slab_minalign() arch_slab_minalign()
#endif

-#ifndef __ASSEMBLY__
-
-#include <linux/bitops.h>
-
#define ICACHEF_ALIASING 0
#define ICACHEF_VPIPT 1
extern unsigned long __icache_flags;
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 373b3ef99f4e..2c7190db4cc0 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -209,6 +209,18 @@ void kmem_dump_obj(void *object);
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
#endif

+/*
+ * Arches can define this function if they want to decide the minimum slab
+ * alignment at runtime. The value returned by the function must be a power
+ * of two and >= ARCH_SLAB_MINALIGN.
+ */
+#ifndef arch_slab_minalign
+static inline size_t arch_slab_minalign(void)
+{
+ return ARCH_SLAB_MINALIGN;
+}
+#endif
+
/*
* kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
* pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
diff --git a/mm/slab.c b/mm/slab.c
index 0edb474edef1..97b756976c8b 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3009,10 +3009,9 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
objp += obj_offset(cachep);
if (cachep->ctor && cachep->flags & SLAB_POISON)
cachep->ctor(objp);
- if (ARCH_SLAB_MINALIGN &&
- ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
- pr_err("0x%px: not aligned to ARCH_SLAB_MINALIGN=%d\n",
- objp, (int)ARCH_SLAB_MINALIGN);
+ if ((unsigned long)objp & (arch_slab_minalign() - 1)) {
+ pr_err("0x%px: not aligned to arch_slab_minalign()=%d\n", objp,
+ (int)arch_slab_minalign());
}
return objp;
}
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 2b3206a2c3b5..33cc49810a54 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -154,8 +154,7 @@ static unsigned int calculate_alignment(slab_flags_t flags,
align = max(align, ralign);
}

- if (align < ARCH_SLAB_MINALIGN)
- align = ARCH_SLAB_MINALIGN;
+ align = max_t(size_t, align, arch_slab_minalign());

return ALIGN(align, sizeof(void *));
}
diff --git a/mm/slob.c b/mm/slob.c
index 40ea6e2d4ccd..3bd2669bd690 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -478,7 +478,7 @@ static __always_inline void *
__do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
{
unsigned int *m;
- int minalign = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+ int minalign = max_t(size_t, ARCH_KMALLOC_MINALIGN, arch_slab_minalign());
void *ret;

gfp &= gfp_allowed_mask;
@@ -555,7 +555,7 @@ void kfree(const void *block)

sp = virt_to_folio(block);
if (folio_test_slab(sp)) {
- int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+ int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, arch_slab_minalign());
unsigned int *m = (unsigned int *)(block - align);
slob_free(m, *m + align);
} else {
@@ -584,7 +584,7 @@ size_t __ksize(const void *block)
if (unlikely(!folio_test_slab(folio)))
return folio_size(folio);

- align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+ align = max_t(size_t, ARCH_KMALLOC_MINALIGN, arch_slab_minalign());
m = (unsigned int *)(block - align);
return SLOB_UNITS(*m) * SLOB_UNIT;
}
--
2.36.0.rc2.479.g8af0fa9b8e-goog

2022-04-25 07:14:02

by Hyeonggon Yoo

[permalink] [raw]

Subject: Re: [PATCH v3] mm: make minimum slab alignment a runtime property

On Fri, Apr 22, 2022 at 01:18:30PM -0700, Peter Collingbourne wrote:
> When CONFIG_KASAN_HW_TAGS is enabled we currently increase the minimum
> slab alignment to 16. This happens even if MTE is not supported in
> hardware or disabled via kasan=off, which creates an unnecessary
> memory overhead in those cases. Eliminate this overhead by making
> the minimum slab alignment a runtime property and only aligning to
> 16 if KASAN is enabled at runtime.
>
> On a DragonBoard 845c (non-MTE hardware) with a kernel built with
> CONFIG_KASAN_HW_TAGS, waiting for quiescence after a full Android
> boot I see the following Slab measurements in /proc/meminfo (median
> of 3 reboots):
>
> Before: 169020 kB
> After: 167304 kB
>
> Link: https://linux-review.googlesource.com/id/I752e725179b43b144153f4b6f584ceb646473ead
> Signed-off-by: Peter Collingbourne <[email protected]>
> Reviewed-by: Andrey Konovalov <[email protected]>
> ---
> v3:
> - go back to ARCH_SLAB_MINALIGN
> - revert changes to fs/binfmt_flat.c
> - update arch_slab_minalign() comment to say that it must be a power of two
>
> v2:
> - use max instead of max_t in flat_stack_align()
>
> arch/arm64/include/asm/cache.h | 17 ++++++++++++-----
> include/linux/slab.h | 12 ++++++++++++
> mm/slab.c | 7 +++----
> mm/slab_common.c | 3 +--
> mm/slob.c | 6 +++---
> 5 files changed, 31 insertions(+), 14 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
> index a074459f8f2f..22b22dc1b1b5 100644
> --- a/arch/arm64/include/asm/cache.h
> +++ b/arch/arm64/include/asm/cache.h
> @@ -6,6 +6,7 @@
> #define __ASM_CACHE_H
>
> #include <asm/cputype.h>
> +#include <asm/mte-def.h>
>
> #define CTR_L1IP_SHIFT 14
> #define CTR_L1IP_MASK 3
> @@ -49,16 +50,22 @@
> */
> #define ARCH_DMA_MINALIGN (128)
>
> +#ifndef __ASSEMBLY__
> +
> +#include <linux/bitops.h>
> +#include <linux/kasan-enabled.h>
> +
> #ifdef CONFIG_KASAN_SW_TAGS
> #define ARCH_SLAB_MINALIGN (1ULL << KASAN_SHADOW_SCALE_SHIFT)
> #elif defined(CONFIG_KASAN_HW_TAGS)
> -#define ARCH_SLAB_MINALIGN MTE_GRANULE_SIZE
> +static inline size_t arch_slab_minalign(void)
> +{
> + return kasan_hw_tags_enabled() ? MTE_GRANULE_SIZE :
> + __alignof__(unsigned long long);
> +}
> +#define arch_slab_minalign() arch_slab_minalign()
> #endif
>
> -#ifndef __ASSEMBLY__
> -
> -#include <linux/bitops.h>
> -
> #define ICACHEF_ALIASING 0
> #define ICACHEF_VPIPT 1
> extern unsigned long __icache_flags;
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 373b3ef99f4e..2c7190db4cc0 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -209,6 +209,18 @@ void kmem_dump_obj(void *object);
> #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
> #endif
>
> +/*
> + * Arches can define this function if they want to decide the minimum slab
> + * alignment at runtime. The value returned by the function must be a power
> + * of two and >= ARCH_SLAB_MINALIGN.
> + */
> +#ifndef arch_slab_minalign
> +static inline size_t arch_slab_minalign(void)
> +{
> + return ARCH_SLAB_MINALIGN;
> +}
> +#endif
> +
> /*
> * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
> * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
> diff --git a/mm/slab.c b/mm/slab.c
> index 0edb474edef1..97b756976c8b 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -3009,10 +3009,9 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
> objp += obj_offset(cachep);
> if (cachep->ctor && cachep->flags & SLAB_POISON)
> cachep->ctor(objp);
> - if (ARCH_SLAB_MINALIGN &&
> - ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
> - pr_err("0x%px: not aligned to ARCH_SLAB_MINALIGN=%d\n",
> - objp, (int)ARCH_SLAB_MINALIGN);
> + if ((unsigned long)objp & (arch_slab_minalign() - 1)) {
> + pr_err("0x%px: not aligned to arch_slab_minalign()=%d\n", objp,
> + (int)arch_slab_minalign());
> }
> return objp;
> }
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 2b3206a2c3b5..33cc49810a54 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -154,8 +154,7 @@ static unsigned int calculate_alignment(slab_flags_t flags,
> align = max(align, ralign);
> }
>
> - if (align < ARCH_SLAB_MINALIGN)
> - align = ARCH_SLAB_MINALIGN;
> + align = max_t(size_t, align, arch_slab_minalign());
>
> return ALIGN(align, sizeof(void *));
> }
> diff --git a/mm/slob.c b/mm/slob.c
> index 40ea6e2d4ccd..3bd2669bd690 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c
> @@ -478,7 +478,7 @@ static __always_inline void *
> __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
> {
> unsigned int *m;
> - int minalign = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
> + int minalign = max_t(size_t, ARCH_KMALLOC_MINALIGN, arch_slab_minalign());
> void *ret;
>
> gfp &= gfp_allowed_mask;
> @@ -555,7 +555,7 @@ void kfree(const void *block)
>
> sp = virt_to_folio(block);
> if (folio_test_slab(sp)) {
> - int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
> + int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, arch_slab_minalign());
> unsigned int *m = (unsigned int *)(block - align);
> slob_free(m, *m + align);
> } else {
> @@ -584,7 +584,7 @@ size_t __ksize(const void *block)
> if (unlikely(!folio_test_slab(folio)))
> return folio_size(folio);
>
> - align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
> + align = max_t(size_t, ARCH_KMALLOC_MINALIGN, arch_slab_minalign());
> m = (unsigned int *)(block - align);
> return SLOB_UNITS(*m) * SLOB_UNIT;
> }
> --
> 2.36.0.rc2.479.g8af0fa9b8e-goog
>

Looks good to me.
Reviewed-by: Hyeonggon Yoo <[email protected]>

And work properly on my arm64 machine (no MTE support)
Tested-by: Hyeonggon Yoo <[email protected]>

Thanks!

--
Thanks,
Hyeonggon

2022-04-25 11:23:17

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH v3] mm: make minimum slab alignment a runtime property

Hi Peter,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on hnaz-mm/master]

url: https://github.com/intel-lab-lkp/linux/commits/Peter-Collingbourne/mm-make-minimum-slab-alignment-a-runtime-property/20220423-042024
base: https://github.com/hnaz/linux-mm master
config: arm64-buildonly-randconfig-r002-20220425 (https://download.01.org/0day-ci/archive/20220425/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1cddcfdc3c683b393df1a5c9063252eb60e52818)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm64 cross compiling tool for clang build
# apt-get install binutils-aarch64-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/3aef97055dd4a480e05dff758164f153aaddbb49
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Peter-Collingbourne/mm-make-minimum-slab-alignment-a-runtime-property/20220423-042024
git checkout 3aef97055dd4a480e05dff758164f153aaddbb49
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 prepare

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>

All errors (new ones prefixed by >>):

In file included from kernel/bounds.c:10:
In file included from include/linux/page-flags.h:10:
In file included from include/linux/bug.h:5:
In file included from arch/arm64/include/asm/bug.h:26:
In file included from include/asm-generic/bug.h:22:
In file included from include/linux/printk.h:9:
In file included from include/linux/cache.h:6:
In file included from arch/arm64/include/asm/cache.h:56:
In file included from include/linux/kasan-enabled.h:5:
In file included from include/linux/static_key.h:1:
>> include/linux/jump_label.h:285:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
STATIC_KEY_CHECK_USE(key);
^
include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
#define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
^
include/linux/jump_label.h:291:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
STATIC_KEY_CHECK_USE(key);
^
include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
#define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
^
include/linux/jump_label.h:313:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
STATIC_KEY_CHECK_USE(key);
^
include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
#define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
^
>> include/linux/jump_label.h:316:3: error: call to undeclared function 'WARN_ON_ONCE'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
^
include/linux/jump_label.h:324:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
STATIC_KEY_CHECK_USE(key);
^
include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
#define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
^
include/linux/jump_label.h:327:3: error: call to undeclared function 'WARN_ON_ONCE'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
^
6 errors generated.
make[2]: *** [scripts/Makefile.build:122: kernel/bounds.s] Error 1
make[2]: Target '__build' not remade because of errors.
make[1]: *** [Makefile:1283: prepare0] Error 2
make[1]: Target 'prepare' not remade because of errors.
make: *** [Makefile:226: __sub-make] Error 2
make: Target 'prepare' not remade because of errors.

vim +/WARN +285 include/linux/jump_label.h

bf5438fca2950b Jason Baron 2010-09-17 282
c5905afb0ee655 Ingo Molnar 2012-02-24 283 static inline void static_key_slow_inc(struct static_key *key)
d430d3d7e646eb Jason Baron 2011-03-16 284 {
5cdda5117e125e Borislav Petkov 2017-10-18 @285 STATIC_KEY_CHECK_USE(key);
d430d3d7e646eb Jason Baron 2011-03-16 286 atomic_inc(&key->enabled);
d430d3d7e646eb Jason Baron 2011-03-16 287 }
bf5438fca2950b Jason Baron 2010-09-17 288
c5905afb0ee655 Ingo Molnar 2012-02-24 289 static inline void static_key_slow_dec(struct static_key *key)
bf5438fca2950b Jason Baron 2010-09-17 290 {
5cdda5117e125e Borislav Petkov 2017-10-18 291 STATIC_KEY_CHECK_USE(key);
d430d3d7e646eb Jason Baron 2011-03-16 292 atomic_dec(&key->enabled);
bf5438fca2950b Jason Baron 2010-09-17 293 }
bf5438fca2950b Jason Baron 2010-09-17 294
ce48c146495a1a Peter Zijlstra 2018-01-22 295 #define static_key_slow_inc_cpuslocked(key) static_key_slow_inc(key)
ce48c146495a1a Peter Zijlstra 2018-01-22 296 #define static_key_slow_dec_cpuslocked(key) static_key_slow_dec(key)
ce48c146495a1a Peter Zijlstra 2018-01-22 297
4c3ef6d79328c0 Jason Baron 2010-09-17 298 static inline int jump_label_text_reserved(void *start, void *end)
4c3ef6d79328c0 Jason Baron 2010-09-17 299 {
4c3ef6d79328c0 Jason Baron 2010-09-17 300 return 0;
4c3ef6d79328c0 Jason Baron 2010-09-17 301 }
4c3ef6d79328c0 Jason Baron 2010-09-17 302
91bad2f8d30574 Jason Baron 2010-10-01 303 static inline void jump_label_lock(void) {}
91bad2f8d30574 Jason Baron 2010-10-01 304 static inline void jump_label_unlock(void) {}
91bad2f8d30574 Jason Baron 2010-10-01 305
d430d3d7e646eb Jason Baron 2011-03-16 306 static inline int jump_label_apply_nops(struct module *mod)
d430d3d7e646eb Jason Baron 2011-03-16 307 {
d430d3d7e646eb Jason Baron 2011-03-16 308 return 0;
d430d3d7e646eb Jason Baron 2011-03-16 309 }
b202952075f626 Gleb Natapov 2011-11-27 310
e33886b38cc82a Peter Zijlstra 2015-07-24 311 static inline void static_key_enable(struct static_key *key)
e33886b38cc82a Peter Zijlstra 2015-07-24 312 {
5cdda5117e125e Borislav Petkov 2017-10-18 313 STATIC_KEY_CHECK_USE(key);
e33886b38cc82a Peter Zijlstra 2015-07-24 314
1dbb6704de91b1 Paolo Bonzini 2017-08-01 315 if (atomic_read(&key->enabled) != 0) {
1dbb6704de91b1 Paolo Bonzini 2017-08-01 @316 WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
1dbb6704de91b1 Paolo Bonzini 2017-08-01 317 return;
1dbb6704de91b1 Paolo Bonzini 2017-08-01 318 }
1dbb6704de91b1 Paolo Bonzini 2017-08-01 319 atomic_set(&key->enabled, 1);
e33886b38cc82a Peter Zijlstra 2015-07-24 320 }
e33886b38cc82a Peter Zijlstra 2015-07-24 321

--
0-DAY CI Kernel Test Service
https://01.org/lkp

2022-04-25 13:33:01

by David Rientjes

[permalink] [raw]

Subject: Re: [PATCH v3] mm: make minimum slab alignment a runtime property

On Fri, 22 Apr 2022, Peter Collingbourne wrote:

> When CONFIG_KASAN_HW_TAGS is enabled we currently increase the minimum
> slab alignment to 16. This happens even if MTE is not supported in
> hardware or disabled via kasan=off, which creates an unnecessary
> memory overhead in those cases. Eliminate this overhead by making
> the minimum slab alignment a runtime property and only aligning to
> 16 if KASAN is enabled at runtime.
>
> On a DragonBoard 845c (non-MTE hardware) with a kernel built with
> CONFIG_KASAN_HW_TAGS, waiting for quiescence after a full Android
> boot I see the following Slab measurements in /proc/meminfo (median
> of 3 reboots):
>
> Before: 169020 kB
> After: 167304 kB
>
> Link: https://linux-review.googlesource.com/id/I752e725179b43b144153f4b6f584ceb646473ead
> Signed-off-by: Peter Collingbourne <[email protected]>
> Reviewed-by: Andrey Konovalov <[email protected]>

Acked-by: David Rientjes <[email protected]>

The command line options are described by
Documentation/dev-tools/kasan.rst but it doesn't look like a update is
necessary. I think the assumption today is that if we're using kasan=off
then we aren't doing the alignment.

I do wonder why kasan=off is not at least mentioned in
Documentation/admin-guide/kernel-parameters.txt and perhaps for all other
kasan options point the reader to Documentation/dev-tools/kasan.rst.

2022-04-25 23:46:55

by Catalin Marinas

[permalink] [raw]

Subject: Re: [PATCH v3] mm: make minimum slab alignment a runtime property

2022-04-27 10:06:01

by Peter Collingbourne

[permalink] [raw]

Subject: Re: [PATCH v3] mm: make minimum slab alignment a runtime property

On Tue, Apr 26, 2022 at 8:12 AM Vlastimil Babka <[email protected]> wrote:
>
> On 4/25/22 07:12, kernel test robot wrote:
> > Hi Peter,
> >
> > Thank you for the patch! Yet something to improve:
> >
> > [auto build test ERROR on hnaz-mm/master]
> >
> > url: https://github.com/intel-lab-lkp/linux/commits/Peter-Collingbourne/mm-make-minimum-slab-alignment-a-runtime-property/20220423-042024
> > base: https://github.com/hnaz/linux-mm master
> > config: arm64-buildonly-randconfig-r002-20220425 (https://download.01.org/0day-ci/archive/20220425/[email protected]/config)
> > compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1cddcfdc3c683b393df1a5c9063252eb60e52818)
> > reproduce (this is a W=1 build):
> > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > chmod +x ~/bin/make.cross
> > # install arm64 cross compiling tool for clang build
> > # apt-get install binutils-aarch64-linux-gnu
> > # https://github.com/intel-lab-lkp/linux/commit/3aef97055dd4a480e05dff758164f153aaddbb49
> > git remote add linux-review https://github.com/intel-lab-lkp/linux
> > git fetch --no-tags linux-review Peter-Collingbourne/mm-make-minimum-slab-alignment-a-runtime-property/20220423-042024
> > git checkout 3aef97055dd4a480e05dff758164f153aaddbb49
> > # save the config file
> > mkdir build_dir && cp config build_dir/.config
> > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 prepare
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <[email protected]>
> >
> > All errors (new ones prefixed by >>):
> >
> > In file included from kernel/bounds.c:10:
> > In file included from include/linux/page-flags.h:10:
> > In file included from include/linux/bug.h:5:
> > In file included from arch/arm64/include/asm/bug.h:26:
> > In file included from include/asm-generic/bug.h:22:
> > In file included from include/linux/printk.h:9:
> > In file included from include/linux/cache.h:6:
> > In file included from arch/arm64/include/asm/cache.h:56:
> > In file included from include/linux/kasan-enabled.h:5:
> > In file included from include/linux/static_key.h:1:
>
> Hmm looks like a circular include, cache.h is too "low-level" in the
> hierarchy to bring in kasan->static_key->jump_label.h definitions?
> jump_label.h does include bug.h, but we have it above already and have
> already passed #define _LINUX_BUG_H.
>
> So, a different kind of header with arm64-specific variant?

The fix that I'm pursuing starts with:

diff --git a/include/linux/printk.h b/include/linux/printk.h
index 1522df223c0f..8e8d74edf121 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -6,7 +6,6 @@
#include <linux/init.h>
#include <linux/kern_levels.h>
#include <linux/linkage.h>
-#include <linux/cache.h>
#include <linux/ratelimit_types.h>
#include <linux/once_lite.h>

and fixing the fallout from code that was including printk.h and
depending on something from cache.h. So far I haven't found much, only
3 fixups required for an arm64 defconfig kernel but I'm trying some
more configs as well.

Peter

2022-04-27 10:43:40

by Vlastimil Babka

[permalink] [raw]

Subject: Re: [PATCH v3] mm: make minimum slab alignment a runtime property

On 4/25/22 07:12, kernel test robot wrote:
> Hi Peter,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on hnaz-mm/master]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Peter-Collingbourne/mm-make-minimum-slab-alignment-a-runtime-property/20220423-042024
> base: https://github.com/hnaz/linux-mm master
> config: arm64-buildonly-randconfig-r002-20220425 (https://download.01.org/0day-ci/archive/20220425/[email protected]/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1cddcfdc3c683b393df1a5c9063252eb60e52818)
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # install arm64 cross compiling tool for clang build
> # apt-get install binutils-aarch64-linux-gnu
> # https://github.com/intel-lab-lkp/linux/commit/3aef97055dd4a480e05dff758164f153aaddbb49
> git remote add linux-review https://github.com/intel-lab-lkp/linux
> git fetch --no-tags linux-review Peter-Collingbourne/mm-make-minimum-slab-alignment-a-runtime-property/20220423-042024
> git checkout 3aef97055dd4a480e05dff758164f153aaddbb49
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 prepare
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All errors (new ones prefixed by >>):
>
> In file included from kernel/bounds.c:10:
> In file included from include/linux/page-flags.h:10:
> In file included from include/linux/bug.h:5:
> In file included from arch/arm64/include/asm/bug.h:26:
> In file included from include/asm-generic/bug.h:22:
> In file included from include/linux/printk.h:9:
> In file included from include/linux/cache.h:6:
> In file included from arch/arm64/include/asm/cache.h:56:
> In file included from include/linux/kasan-enabled.h:5:
> In file included from include/linux/static_key.h:1:

Hmm looks like a circular include, cache.h is too "low-level" in the
hierarchy to bring in kasan->static_key->jump_label.h definitions?
jump_label.h does include bug.h, but we have it above already and have
already passed #define _LINUX_BUG_H.

So, a different kind of header with arm64-specific variant?

>>> include/linux/jump_label.h:285:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> STATIC_KEY_CHECK_USE(key);
> ^
> include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
> #define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
> ^
> include/linux/jump_label.h:291:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> STATIC_KEY_CHECK_USE(key);
> ^
> include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
> #define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
> ^
> include/linux/jump_label.h:313:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> STATIC_KEY_CHECK_USE(key);
> ^
> include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
> #define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
> ^
>>> include/linux/jump_label.h:316:3: error: call to undeclared function 'WARN_ON_ONCE'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
> ^
> include/linux/jump_label.h:324:2: error: call to undeclared function 'WARN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> STATIC_KEY_CHECK_USE(key);
> ^
> include/linux/jump_label.h:81:35: note: expanded from macro 'STATIC_KEY_CHECK_USE'
> #define STATIC_KEY_CHECK_USE(key) WARN(!static_key_initialized, \
> ^
> include/linux/jump_label.h:327:3: error: call to undeclared function 'WARN_ON_ONCE'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
> ^
> 6 errors generated.
> make[2]: *** [scripts/Makefile.build:122: kernel/bounds.s] Error 1
> make[2]: Target '__build' not remade because of errors.
> make[1]: *** [Makefile:1283: prepare0] Error 2
> make[1]: Target 'prepare' not remade because of errors.
> make: *** [Makefile:226: __sub-make] Error 2
> make: Target 'prepare' not remade because of errors.
>
>
> vim +/WARN +285 include/linux/jump_label.h
>
> bf5438fca2950b Jason Baron 2010-09-17 282
> c5905afb0ee655 Ingo Molnar 2012-02-24 283 static inline void static_key_slow_inc(struct static_key *key)
> d430d3d7e646eb Jason Baron 2011-03-16 284 {
> 5cdda5117e125e Borislav Petkov 2017-10-18 @285 STATIC_KEY_CHECK_USE(key);
> d430d3d7e646eb Jason Baron 2011-03-16 286 atomic_inc(&key->enabled);
> d430d3d7e646eb Jason Baron 2011-03-16 287 }
> bf5438fca2950b Jason Baron 2010-09-17 288
> c5905afb0ee655 Ingo Molnar 2012-02-24 289 static inline void static_key_slow_dec(struct static_key *key)
> bf5438fca2950b Jason Baron 2010-09-17 290 {
> 5cdda5117e125e Borislav Petkov 2017-10-18 291 STATIC_KEY_CHECK_USE(key);
> d430d3d7e646eb Jason Baron 2011-03-16 292 atomic_dec(&key->enabled);
> bf5438fca2950b Jason Baron 2010-09-17 293 }
> bf5438fca2950b Jason Baron 2010-09-17 294
> ce48c146495a1a Peter Zijlstra 2018-01-22 295 #define static_key_slow_inc_cpuslocked(key) static_key_slow_inc(key)
> ce48c146495a1a Peter Zijlstra 2018-01-22 296 #define static_key_slow_dec_cpuslocked(key) static_key_slow_dec(key)
> ce48c146495a1a Peter Zijlstra 2018-01-22 297
> 4c3ef6d79328c0 Jason Baron 2010-09-17 298 static inline int jump_label_text_reserved(void *start, void *end)
> 4c3ef6d79328c0 Jason Baron 2010-09-17 299 {
> 4c3ef6d79328c0 Jason Baron 2010-09-17 300 return 0;
> 4c3ef6d79328c0 Jason Baron 2010-09-17 301 }
> 4c3ef6d79328c0 Jason Baron 2010-09-17 302
> 91bad2f8d30574 Jason Baron 2010-10-01 303 static inline void jump_label_lock(void) {}
> 91bad2f8d30574 Jason Baron 2010-10-01 304 static inline void jump_label_unlock(void) {}
> 91bad2f8d30574 Jason Baron 2010-10-01 305
> d430d3d7e646eb Jason Baron 2011-03-16 306 static inline int jump_label_apply_nops(struct module *mod)
> d430d3d7e646eb Jason Baron 2011-03-16 307 {
> d430d3d7e646eb Jason Baron 2011-03-16 308 return 0;
> d430d3d7e646eb Jason Baron 2011-03-16 309 }
> b202952075f626 Gleb Natapov 2011-11-27 310
> e33886b38cc82a Peter Zijlstra 2015-07-24 311 static inline void static_key_enable(struct static_key *key)
> e33886b38cc82a Peter Zijlstra 2015-07-24 312 {
> 5cdda5117e125e Borislav Petkov 2017-10-18 313 STATIC_KEY_CHECK_USE(key);
> e33886b38cc82a Peter Zijlstra 2015-07-24 314
> 1dbb6704de91b1 Paolo Bonzini 2017-08-01 315 if (atomic_read(&key->enabled) != 0) {
> 1dbb6704de91b1 Paolo Bonzini 2017-08-01 @316 WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
> 1dbb6704de91b1 Paolo Bonzini 2017-08-01 317 return;
> 1dbb6704de91b1 Paolo Bonzini 2017-08-01 318 }
> 1dbb6704de91b1 Paolo Bonzini 2017-08-01 319 atomic_set(&key->enabled, 1);
> e33886b38cc82a Peter Zijlstra 2015-07-24 320 }
> e33886b38cc82a Peter Zijlstra 2015-07-24 321
>