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[PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller

Greg Kroah-Hartman posted 1 patch 4 years, 4 months ago 
include/linux/slab.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
[PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller
Posted by Greg Kroah-Hartman 4 years, 4 months ago 
Commit c37495d6254c ("slab: add __alloc_size attributes for better
bounds checking") added __alloc_size attributes to a bunch of kmalloc
function prototypes.  Unfortunately the change to __kmalloc_track_caller
seems to cause clang to generate broken code and the first time this is
called when booting, the box will crash.

While the compiler problems are being reworked and attempted to be
solved, let's just drop the attribute to solve the issue now.  Once it
is resolved it can be added back.

Fixes: c37495d6254c ("slab: add __alloc_size attributes for better bounds checking")
Cc: stable <stable@vger.kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
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: Vlastimil Babka <vbabka@suse.cz>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Cc: llvm@lists.linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/slab.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 37bde99b74af..5b6193fd8bd9 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -660,8 +660,7 @@ static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flag
  * allocator where we care about the real place the memory allocation
  * request comes from.
  */
-extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
-				   __alloc_size(1);
+extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller);
 #define kmalloc_track_caller(size, flags) \
 	__kmalloc_track_caller(size, flags, _RET_IP_)
 
-- 
2.35.1
Re: [PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller
Posted by Vlastimil Babka 4 years, 4 months ago 
On 2/18/22 14:13, Greg Kroah-Hartman wrote:
> Commit c37495d6254c ("slab: add __alloc_size attributes for better
> bounds checking") added __alloc_size attributes to a bunch of kmalloc
> function prototypes.  Unfortunately the change to __kmalloc_track_caller
> seems to cause clang to generate broken code and the first time this is
> called when booting, the box will crash.
> 
> While the compiler problems are being reworked and attempted to be
> solved, let's just drop the attribute to solve the issue now.  Once it
> is resolved it can be added back.

Could we instead wrap it in some #ifdef that' only true for clang build?
That would make the workaround more precise and self-documented. Even
better if it can trigger using clang version range and once a fixed
clang version is here, it can be updated to stay true for older clangs.

> Fixes: c37495d6254c ("slab: add __alloc_size attributes for better bounds checking")
> Cc: stable <stable@vger.kernel.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Daniel Micay <danielmicay@gmail.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> 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: Vlastimil Babka <vbabka@suse.cz>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Cc: llvm@lists.linux.dev
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  include/linux/slab.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 37bde99b74af..5b6193fd8bd9 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -660,8 +660,7 @@ static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flag
>   * allocator where we care about the real place the memory allocation
>   * request comes from.
>   */
> -extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
> -				   __alloc_size(1);
> +extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller);
>  #define kmalloc_track_caller(size, flags) \
>  	__kmalloc_track_caller(size, flags, _RET_IP_)
>
Re: [PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller
Posted by Nick Desaulniers 4 years, 4 months ago 
On Fri, Feb 18, 2022 at 5:14 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> Commit c37495d6254c ("slab: add __alloc_size attributes for better
> bounds checking") added __alloc_size attributes to a bunch of kmalloc
> function prototypes.  Unfortunately the change to __kmalloc_track_caller
> seems to cause clang to generate broken code and the first time this is
> called when booting, the box will crash.
>
> While the compiler problems are being reworked and attempted to be
> solved, let's just drop the attribute to solve the issue now.  Once it
> is resolved it can be added back.

Sorry about the mess; we'll get it cleaned up!
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1599

>
> Fixes: c37495d6254c ("slab: add __alloc_size attributes for better bounds checking")
> Cc: stable <stable@vger.kernel.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Daniel Micay <danielmicay@gmail.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> 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: Vlastimil Babka <vbabka@suse.cz>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Cc: llvm@lists.linux.dev
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  include/linux/slab.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 37bde99b74af..5b6193fd8bd9 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -660,8 +660,7 @@ static inline __alloc_size(1, 2) void *kcalloc(size_t n, size_t size, gfp_t flag
>   * allocator where we care about the real place the memory allocation
>   * request comes from.
>   */
> -extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
> -                                  __alloc_size(1);
> +extern void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller);
>  #define kmalloc_track_caller(size, flags) \
>         __kmalloc_track_caller(size, flags, _RET_IP_)
>
> --
> 2.35.1
>


-- 
Thanks,
~Nick Desaulniers
Re: [PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller
Posted by Kees Cook 4 years, 4 months ago 
On Fri, Feb 18, 2022 at 09:19:51AM -0800, Nick Desaulniers wrote:
> On Fri, Feb 18, 2022 at 5:14 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > Commit c37495d6254c ("slab: add __alloc_size attributes for better
> > bounds checking") added __alloc_size attributes to a bunch of kmalloc
> > function prototypes.  Unfortunately the change to __kmalloc_track_caller
> > seems to cause clang to generate broken code and the first time this is
> > called when booting, the box will crash.
> >
> > While the compiler problems are being reworked and attempted to be
> > solved, let's just drop the attribute to solve the issue now.  Once it
> > is resolved it can be added back.
> 
> Sorry about the mess; we'll get it cleaned up!
> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1599

Thanks for the issue link!

Acked-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook
Re: [PATCH] slab: remove __alloc_size attribute from __kmalloc_track_caller
Posted by David Rientjes 4 years, 4 months ago 
On Fri, 18 Feb 2022, Greg Kroah-Hartman wrote:

> Commit c37495d6254c ("slab: add __alloc_size attributes for better
> bounds checking") added __alloc_size attributes to a bunch of kmalloc
> function prototypes.  Unfortunately the change to __kmalloc_track_caller
> seems to cause clang to generate broken code and the first time this is
> called when booting, the box will crash.
> 
> While the compiler problems are being reworked and attempted to be
> solved, let's just drop the attribute to solve the issue now.  Once it
> is resolved it can be added back.
> 
> Fixes: c37495d6254c ("slab: add __alloc_size attributes for better bounds checking")
> Cc: stable <stable@vger.kernel.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Daniel Micay <danielmicay@gmail.com>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> 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: Vlastimil Babka <vbabka@suse.cz>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Cc: llvm@lists.linux.dev
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: David Rientjes <rientjes@google.com>

Patchew 2.1-devel-ea86937

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