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[PATCH 3/6] slab: Provide functional __alloc_size() hints to kmalloc_trace*()

Kees Cook posted 6 patches 3 years, 5 months ago
There is a newer version of this series
[PATCH 3/6] slab: Provide functional __alloc_size() hints to kmalloc_trace*()
Posted by Kees Cook 3 years, 5 months ago 
Since GCC cannot apply the __alloc_size attributes to inlines[1], all
allocator inlines need to explicitly call into extern functions that
contain a size argument. Provide these wrappers that end up just
ignoring the size argument for the actual allocation.

This allows CONFIG_FORTIFY_SOURCE=y to see all various dynamic allocation
sizes under GCC 12+ and all supported Clang versions.

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503

Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/slab.h |  8 ++++++--
 mm/slab_common.c     | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 970e9504949e..051d86ca31a8 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -442,6 +442,8 @@ static_assert(PAGE_SHIFT <= 20);
 
 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
+void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
+			     __assume_slab_alignment __alloc_size(3);
 void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
 			   gfp_t gfpflags) __assume_slab_alignment __malloc;
 void kmem_cache_free(struct kmem_cache *s, void *objp);
@@ -469,6 +471,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignm
 							 __alloc_size(1);
 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
 									 __malloc;
+void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
+				  __assume_slab_alignment __alloc_size(4);
 
 #ifdef CONFIG_TRACING
 void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
@@ -482,7 +486,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
 static __always_inline __alloc_size(3)
 void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
 {
-	void *ret = kmem_cache_alloc(s, flags);
+	void *ret = kmem_cache_alloc_sized(s, flags, size);
 
 	ret = kasan_kmalloc(s, ret, size, flags);
 	return ret;
@@ -492,7 +496,7 @@ static __always_inline __alloc_size(4)
 void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
 			 int node, size_t size)
 {
-	void *ret = kmem_cache_alloc_node(s, gfpflags, node);
+	void *ret = kmem_cache_alloc_node_sized(s, gfpflags, node, size);
 
 	ret = kasan_kmalloc(s, ret, size, gfpflags);
 	return ret;
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 33b1886b06eb..5fa547539a6a 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1457,6 +1457,20 @@ size_t ksize(const void *objp)
 }
 EXPORT_SYMBOL(ksize);
 
+/* Wrapper so __alloc_size() can see the actual allocation size. */
+void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
+{
+	return kmem_cache_alloc(s, flags);
+}
+EXPORT_SYMBOL(kmem_cache_alloc_sized);
+
+/* Wrapper so __alloc_size() can see the actual allocation size. */
+void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
+{
+	return kmem_cache_alloc_node(s, flags, node);
+}
+EXPORT_SYMBOL(kmem_cache_alloc_node_sized);
+
 /* Tracepoints definitions. */
 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
-- 
2.34.1
Re: [PATCH 3/6] slab: Provide functional __alloc_size() hints to kmalloc_trace*()
Posted by Hyeonggon Yoo 3 years, 5 months ago 
On Tue, Nov 01, 2022 at 03:33:11PM -0700, Kees Cook wrote:
> Since GCC cannot apply the __alloc_size attributes to inlines[1], all
> allocator inlines need to explicitly call into extern functions that
> contain a size argument. Provide these wrappers that end up just
> ignoring the size argument for the actual allocation.
> 
> This allows CONFIG_FORTIFY_SOURCE=y to see all various dynamic allocation
> sizes under GCC 12+ and all supported Clang versions.
> 
> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503
> 
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Pekka Enberg <penberg@kernel.org>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Roman Gushchin <roman.gushchin@linux.dev>
> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Cc: linux-mm@kvack.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  include/linux/slab.h |  8 ++++++--
>  mm/slab_common.c     | 14 ++++++++++++++
>  2 files changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 970e9504949e..051d86ca31a8 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -442,6 +442,8 @@ static_assert(PAGE_SHIFT <= 20);
>  
>  void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
>  void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
> +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> +			     __assume_slab_alignment __alloc_size(3);
>  void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
>  			   gfp_t gfpflags) __assume_slab_alignment __malloc;
>  void kmem_cache_free(struct kmem_cache *s, void *objp);
> @@ -469,6 +471,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignm
>  							 __alloc_size(1);
>  void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
>  									 __malloc;
> +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> +				  __assume_slab_alignment __alloc_size(4);
>  
>  #ifdef CONFIG_TRACING
>  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
> @@ -482,7 +486,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
>  static __always_inline __alloc_size(3)
>  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
>  {
> -	void *ret = kmem_cache_alloc(s, flags);
> +	void *ret = kmem_cache_alloc_sized(s, flags, size);
>  
>  	ret = kasan_kmalloc(s, ret, size, flags);
>  	return ret;
> @@ -492,7 +496,7 @@ static __always_inline __alloc_size(4)
>  void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
>  			 int node, size_t size)
>  {
> -	void *ret = kmem_cache_alloc_node(s, gfpflags, node);
> +	void *ret = kmem_cache_alloc_node_sized(s, gfpflags, node, size);
>  
>  	ret = kasan_kmalloc(s, ret, size, gfpflags);
>  	return ret;
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 33b1886b06eb..5fa547539a6a 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -1457,6 +1457,20 @@ size_t ksize(const void *objp)
>  }
>  EXPORT_SYMBOL(ksize);
>  
> +/* Wrapper so __alloc_size() can see the actual allocation size. */
> +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> +{
> +	return kmem_cache_alloc(s, flags);
> +}
> +EXPORT_SYMBOL(kmem_cache_alloc_sized);
> +
> +/* Wrapper so __alloc_size() can see the actual allocation size. */
> +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> +{
> +	return kmem_cache_alloc_node(s, flags, node);
> +}
> +EXPORT_SYMBOL(kmem_cache_alloc_node_sized);

The reason that we have two implementations of kmalloc_trace*
depending on CONFIG_TRACING is to save additional function call when
CONFIG_TRACING is not set.

With this patch there is no reason to keep both.
So let's drop #ifdefs and use single implementation in mm/slab_common.c.

Thanks!

>  /* Tracepoints definitions. */
>  EXPORT_TRACEPOINT_SYMBOL(kmalloc);
>  EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
> -- 
> 2.34.1
> 

-- 
Hyeonggon
Re: [PATCH 3/6] slab: Provide functional __alloc_size() hints to kmalloc_trace*()
Posted by Kees Cook 3 years, 5 months ago 
On Thu, Nov 03, 2022 at 11:16:53PM +0900, Hyeonggon Yoo wrote:
> On Tue, Nov 01, 2022 at 03:33:11PM -0700, Kees Cook wrote:
> > Since GCC cannot apply the __alloc_size attributes to inlines[1], all
> > allocator inlines need to explicitly call into extern functions that
> > contain a size argument. Provide these wrappers that end up just
> > ignoring the size argument for the actual allocation.
> > 
> > This allows CONFIG_FORTIFY_SOURCE=y to see all various dynamic allocation
> > sizes under GCC 12+ and all supported Clang versions.
> > 
> > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503
> > 
> > Cc: Vlastimil Babka <vbabka@suse.cz>
> > Cc: Christoph Lameter <cl@linux.com>
> > Cc: Pekka Enberg <penberg@kernel.org>
> > Cc: David Rientjes <rientjes@google.com>
> > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Roman Gushchin <roman.gushchin@linux.dev>
> > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Cc: linux-mm@kvack.org
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  include/linux/slab.h |  8 ++++++--
> >  mm/slab_common.c     | 14 ++++++++++++++
> >  2 files changed, 20 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index 970e9504949e..051d86ca31a8 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -442,6 +442,8 @@ static_assert(PAGE_SHIFT <= 20);
> >  
> >  void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
> >  void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
> > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> > +			     __assume_slab_alignment __alloc_size(3);
> >  void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
> >  			   gfp_t gfpflags) __assume_slab_alignment __malloc;
> >  void kmem_cache_free(struct kmem_cache *s, void *objp);
> > @@ -469,6 +471,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignm
> >  							 __alloc_size(1);
> >  void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
> >  									 __malloc;
> > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> > +				  __assume_slab_alignment __alloc_size(4);
> >  
> >  #ifdef CONFIG_TRACING
> >  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
> > @@ -482,7 +486,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
> >  static __always_inline __alloc_size(3)
> >  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
> >  {
> > -	void *ret = kmem_cache_alloc(s, flags);
> > +	void *ret = kmem_cache_alloc_sized(s, flags, size);
> >  
> >  	ret = kasan_kmalloc(s, ret, size, flags);
> >  	return ret;
> > @@ -492,7 +496,7 @@ static __always_inline __alloc_size(4)
> >  void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
> >  			 int node, size_t size)
> >  {
> > -	void *ret = kmem_cache_alloc_node(s, gfpflags, node);
> > +	void *ret = kmem_cache_alloc_node_sized(s, gfpflags, node, size);
> >  
> >  	ret = kasan_kmalloc(s, ret, size, gfpflags);
> >  	return ret;
> > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > index 33b1886b06eb..5fa547539a6a 100644
> > --- a/mm/slab_common.c
> > +++ b/mm/slab_common.c
> > @@ -1457,6 +1457,20 @@ size_t ksize(const void *objp)
> >  }
> >  EXPORT_SYMBOL(ksize);
> >  
> > +/* Wrapper so __alloc_size() can see the actual allocation size. */
> > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> > +{
> > +	return kmem_cache_alloc(s, flags);
> > +}
> > +EXPORT_SYMBOL(kmem_cache_alloc_sized);
> > +
> > +/* Wrapper so __alloc_size() can see the actual allocation size. */
> > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> > +{
> > +	return kmem_cache_alloc_node(s, flags, node);
> > +}
> > +EXPORT_SYMBOL(kmem_cache_alloc_node_sized);
> 
> The reason that we have two implementations of kmalloc_trace*
> depending on CONFIG_TRACING is to save additional function call when
> CONFIG_TRACING is not set.
> 
> With this patch there is no reason to keep both.
> So let's drop #ifdefs and use single implementation in mm/slab_common.c.

Okay, I'll respin...

-- 
Kees Cook
Re: [PATCH 3/6] slab: Provide functional __alloc_size() hints to kmalloc_trace*()
Posted by Hyeonggon Yoo 3 years, 5 months ago 
On Fri, Nov 04, 2022 at 11:22:42AM -0700, Kees Cook wrote:
> On Thu, Nov 03, 2022 at 11:16:53PM +0900, Hyeonggon Yoo wrote:
> > On Tue, Nov 01, 2022 at 03:33:11PM -0700, Kees Cook wrote:
> > > Since GCC cannot apply the __alloc_size attributes to inlines[1], all
> > > allocator inlines need to explicitly call into extern functions that
> > > contain a size argument. Provide these wrappers that end up just
> > > ignoring the size argument for the actual allocation.
> > > 
> > > This allows CONFIG_FORTIFY_SOURCE=y to see all various dynamic allocation
> > > sizes under GCC 12+ and all supported Clang versions.
> > > 
> > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503
> > > 
> > > Cc: Vlastimil Babka <vbabka@suse.cz>
> > > Cc: Christoph Lameter <cl@linux.com>
> > > Cc: Pekka Enberg <penberg@kernel.org>
> > > Cc: David Rientjes <rientjes@google.com>
> > > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > > Cc: Andrew Morton <akpm@linux-foundation.org>
> > > Cc: Roman Gushchin <roman.gushchin@linux.dev>
> > > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > > Cc: linux-mm@kvack.org
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > ---
> > >  include/linux/slab.h |  8 ++++++--
> > >  mm/slab_common.c     | 14 ++++++++++++++
> > >  2 files changed, 20 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > > index 970e9504949e..051d86ca31a8 100644
> > > --- a/include/linux/slab.h
> > > +++ b/include/linux/slab.h
> > > @@ -442,6 +442,8 @@ static_assert(PAGE_SHIFT <= 20);
> > >  
> > >  void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
> > >  void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
> > > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> > > +			     __assume_slab_alignment __alloc_size(3);
> > >  void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
> > >  			   gfp_t gfpflags) __assume_slab_alignment __malloc;
> > >  void kmem_cache_free(struct kmem_cache *s, void *objp);
> > > @@ -469,6 +471,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignm
> > >  							 __alloc_size(1);
> > >  void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
> > >  									 __malloc;
> > > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> > > +				  __assume_slab_alignment __alloc_size(4);
> > >  
> > >  #ifdef CONFIG_TRACING
> > >  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
> > > @@ -482,7 +486,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
> > >  static __always_inline __alloc_size(3)
> > >  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
> > >  {
> > > -	void *ret = kmem_cache_alloc(s, flags);
> > > +	void *ret = kmem_cache_alloc_sized(s, flags, size);
> > >  
> > >  	ret = kasan_kmalloc(s, ret, size, flags);
> > >  	return ret;
> > > @@ -492,7 +496,7 @@ static __always_inline __alloc_size(4)
> > >  void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
> > >  			 int node, size_t size)
> > >  {
> > > -	void *ret = kmem_cache_alloc_node(s, gfpflags, node);
> > > +	void *ret = kmem_cache_alloc_node_sized(s, gfpflags, node, size);
> > >  
> > >  	ret = kasan_kmalloc(s, ret, size, gfpflags);
> > >  	return ret;
> > > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > > index 33b1886b06eb..5fa547539a6a 100644
> > > --- a/mm/slab_common.c
> > > +++ b/mm/slab_common.c
> > > @@ -1457,6 +1457,20 @@ size_t ksize(const void *objp)
> > >  }
> > >  EXPORT_SYMBOL(ksize);
> > >  
> > > +/* Wrapper so __alloc_size() can see the actual allocation size. */
> > > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> > > +{
> > > +	return kmem_cache_alloc(s, flags);
> > > +}
> > > +EXPORT_SYMBOL(kmem_cache_alloc_sized);
> > > +
> > > +/* Wrapper so __alloc_size() can see the actual allocation size. */
> > > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> > > +{
> > > +	return kmem_cache_alloc_node(s, flags, node);
> > > +}
> > > +EXPORT_SYMBOL(kmem_cache_alloc_node_sized);
> > 
> > The reason that we have two implementations of kmalloc_trace*
> > depending on CONFIG_TRACING is to save additional function call when
> > CONFIG_TRACING is not set.
> > 
> > With this patch there is no reason to keep both.
> > So let's drop #ifdefs and use single implementation in mm/slab_common.c.
> 
> Okay, I'll respin...
> 
> -- 
> Kees Cook

Oh, it seems Vlastimil already did that.
Maybe simply drop this patch in next spin?

https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab.git/commit/?h=slab/for-6.1-rc4/fixes&id=eb4940d4adf590590a9d0c47e38d2799c2ff9670

Thanks!

-- 
Hyeonggon
Re: [PATCH 3/6] slab: Provide functional __alloc_size() hints to kmalloc_trace*()
Posted by Kees Cook 3 years, 5 months ago 
On Sat, Nov 05, 2022 at 10:09:32AM +0900, Hyeonggon Yoo wrote:
> On Fri, Nov 04, 2022 at 11:22:42AM -0700, Kees Cook wrote:
> > On Thu, Nov 03, 2022 at 11:16:53PM +0900, Hyeonggon Yoo wrote:
> > > On Tue, Nov 01, 2022 at 03:33:11PM -0700, Kees Cook wrote:
> > > > Since GCC cannot apply the __alloc_size attributes to inlines[1], all
> > > > allocator inlines need to explicitly call into extern functions that
> > > > contain a size argument. Provide these wrappers that end up just
> > > > ignoring the size argument for the actual allocation.
> > > > 
> > > > This allows CONFIG_FORTIFY_SOURCE=y to see all various dynamic allocation
> > > > sizes under GCC 12+ and all supported Clang versions.
> > > > 
> > > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96503
> > > > 
> > > > Cc: Vlastimil Babka <vbabka@suse.cz>
> > > > Cc: Christoph Lameter <cl@linux.com>
> > > > Cc: Pekka Enberg <penberg@kernel.org>
> > > > Cc: David Rientjes <rientjes@google.com>
> > > > Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > > > Cc: Andrew Morton <akpm@linux-foundation.org>
> > > > Cc: Roman Gushchin <roman.gushchin@linux.dev>
> > > > Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > > > Cc: linux-mm@kvack.org
> > > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > > ---
> > > >  include/linux/slab.h |  8 ++++++--
> > > >  mm/slab_common.c     | 14 ++++++++++++++
> > > >  2 files changed, 20 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > > > index 970e9504949e..051d86ca31a8 100644
> > > > --- a/include/linux/slab.h
> > > > +++ b/include/linux/slab.h
> > > > @@ -442,6 +442,8 @@ static_assert(PAGE_SHIFT <= 20);
> > > >  
> > > >  void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __alloc_size(1);
> > > >  void *kmem_cache_alloc(struct kmem_cache *s, gfp_t flags) __assume_slab_alignment __malloc;
> > > > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> > > > +			     __assume_slab_alignment __alloc_size(3);
> > > >  void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
> > > >  			   gfp_t gfpflags) __assume_slab_alignment __malloc;
> > > >  void kmem_cache_free(struct kmem_cache *s, void *objp);
> > > > @@ -469,6 +471,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignm
> > > >  							 __alloc_size(1);
> > > >  void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node) __assume_slab_alignment
> > > >  									 __malloc;
> > > > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> > > > +				  __assume_slab_alignment __alloc_size(4);
> > > >  
> > > >  #ifdef CONFIG_TRACING
> > > >  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
> > > > @@ -482,7 +486,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
> > > >  static __always_inline __alloc_size(3)
> > > >  void *kmalloc_trace(struct kmem_cache *s, gfp_t flags, size_t size)
> > > >  {
> > > > -	void *ret = kmem_cache_alloc(s, flags);
> > > > +	void *ret = kmem_cache_alloc_sized(s, flags, size);
> > > >  
> > > >  	ret = kasan_kmalloc(s, ret, size, flags);
> > > >  	return ret;
> > > > @@ -492,7 +496,7 @@ static __always_inline __alloc_size(4)
> > > >  void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
> > > >  			 int node, size_t size)
> > > >  {
> > > > -	void *ret = kmem_cache_alloc_node(s, gfpflags, node);
> > > > +	void *ret = kmem_cache_alloc_node_sized(s, gfpflags, node, size);
> > > >  
> > > >  	ret = kasan_kmalloc(s, ret, size, gfpflags);
> > > >  	return ret;
> > > > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > > > index 33b1886b06eb..5fa547539a6a 100644
> > > > --- a/mm/slab_common.c
> > > > +++ b/mm/slab_common.c
> > > > @@ -1457,6 +1457,20 @@ size_t ksize(const void *objp)
> > > >  }
> > > >  EXPORT_SYMBOL(ksize);
> > > >  
> > > > +/* Wrapper so __alloc_size() can see the actual allocation size. */
> > > > +void *kmem_cache_alloc_sized(struct kmem_cache *s, gfp_t flags, size_t size)
> > > > +{
> > > > +	return kmem_cache_alloc(s, flags);
> > > > +}
> > > > +EXPORT_SYMBOL(kmem_cache_alloc_sized);
> > > > +
> > > > +/* Wrapper so __alloc_size() can see the actual allocation size. */
> > > > +void *kmem_cache_alloc_node_sized(struct kmem_cache *s, gfp_t flags, int node, size_t size)
> > > > +{
> > > > +	return kmem_cache_alloc_node(s, flags, node);
> > > > +}
> > > > +EXPORT_SYMBOL(kmem_cache_alloc_node_sized);
> > > 
> > > The reason that we have two implementations of kmalloc_trace*
> > > depending on CONFIG_TRACING is to save additional function call when
> > > CONFIG_TRACING is not set.
> > > 
> > > With this patch there is no reason to keep both.
> > > So let's drop #ifdefs and use single implementation in mm/slab_common.c.
> > 
> > Okay, I'll respin...
> > 
> > -- 
> > Kees Cook
> 
> Oh, it seems Vlastimil already did that.
> Maybe simply drop this patch in next spin?
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab.git/commit/?h=slab/for-6.1-rc4/fixes&id=eb4940d4adf590590a9d0c47e38d2799c2ff9670

Oh! Well, yes, that makes that easy. :)

-- 
Kees Cook

Patchew 2.1-devel-ea86937

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