The macro is only used by i915. Move it to a local header and drop from
the kernel.h.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
---
 drivers/gpu/drm/i915/i915_utils.h | 2 ++
 include/linux/kernel.h            | 2 --
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index a0c892e4c40d..6c197e968305 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -32,6 +32,8 @@
 #include <linux/workqueue.h>
 #include <linux/sched/clock.h>
 
+#define STACK_MAGIC	0xdeadbeef
+
 #ifdef CONFIG_X86
 #include <asm/hypervisor.h>
 #endif
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 5b46924fdff5..61d63c57bc2d 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -40,8 +40,6 @@
 
 #include <uapi/linux/kernel.h>
 
-#define STACK_MAGIC	0xdeadbeef
-
 struct completion;
 struct user;
 
-- 
2.43.0

Le 29/11/2025 à 20:53, Yury Norov (NVIDIA) a écrit :
> The macro is only used by i915. Move it to a local header and drop from
> the kernel.h.

At the begining of the git history we have:

$ git grep STACK_MAGIC 1da177e4c3f41
1da177e4c3f41:arch/h8300/kernel/traps.c:        if (STACK_MAGIC != 
*(unsigned long *)((unsigned long)current+PAGE_SIZE))
1da177e4c3f41:arch/m68k/mac/macints.c:          if (STACK_MAGIC != 
*(unsigned long *)current->kernel_stack_page)
1da177e4c3f41:include/linux/kernel.h:#define STACK_MAGIC        0xdeadbeef

Would be good to know the history of its usage over time.

I see:
- Removed from m68k by 3cd53b14e7c4 ("m68k/mac: Improve NMI handler")
- Removed from h8300 by 1c4b5ecb7ea1 ("remove the h8300 architecture")
- Started being used in i915 selftest by 250f8c8140ac ("drm/i915/gtt: 
Read-only pages for insert_entries on bdw+")

Christophe

> 
> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> ---
>   drivers/gpu/drm/i915/i915_utils.h | 2 ++
>   include/linux/kernel.h            | 2 --
>   2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
> index a0c892e4c40d..6c197e968305 100644
> --- a/drivers/gpu/drm/i915/i915_utils.h
> +++ b/drivers/gpu/drm/i915/i915_utils.h
> @@ -32,6 +32,8 @@
>   #include <linux/workqueue.h>
>   #include <linux/sched/clock.h>
>   
> +#define STACK_MAGIC	0xdeadbeef
> +
>   #ifdef CONFIG_X86
>   #include <asm/hypervisor.h>
>   #endif
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 5b46924fdff5..61d63c57bc2d 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -40,8 +40,6 @@
>   
>   #include <uapi/linux/kernel.h>
>   
> -#define STACK_MAGIC	0xdeadbeef
> -
>   struct completion;
>   struct user;
>   

On Sat, 29 Nov 2025, "Yury Norov (NVIDIA)" <yury.norov@gmail.com> wrote:
> The macro is only used by i915. Move it to a local header and drop from
> the kernel.h.
>
> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
> ---
>  drivers/gpu/drm/i915/i915_utils.h | 2 ++
>  include/linux/kernel.h            | 2 --
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
> index a0c892e4c40d..6c197e968305 100644
> --- a/drivers/gpu/drm/i915/i915_utils.h
> +++ b/drivers/gpu/drm/i915/i915_utils.h

i915_utils.h is on a diet itself. STACK_MAGIC is only used in selftests,
please put this in i915_selftest.h.

I guess also need to include that from gt/selftest_ring_submission.c,
the only one that uses STACK_MAGIC but doesn't include i915_selftest.h.

BR,
Jani.


> @@ -32,6 +32,8 @@
>  #include <linux/workqueue.h>
>  #include <linux/sched/clock.h>
>  
> +#define STACK_MAGIC	0xdeadbeef
> +
>  #ifdef CONFIG_X86
>  #include <asm/hypervisor.h>
>  #endif
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 5b46924fdff5..61d63c57bc2d 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -40,8 +40,6 @@
>  
>  #include <uapi/linux/kernel.h>
>  
> -#define STACK_MAGIC	0xdeadbeef
> -
>  struct completion;
>  struct user;

-- 
Jani Nikula, Intel

On Sat, Nov 29, 2025 at 02:53:00PM -0500, Yury Norov (NVIDIA) wrote:
> The macro is only used by i915. Move it to a local header and drop from
> the kernel.h.

Agree, if one wants to reinstate it, there should be better place for it
(something related to kasan?).

FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko

On 11/29/25 12:32 PM, Andy Shevchenko wrote:
> On Sat, Nov 29, 2025 at 02:53:00PM -0500, Yury Norov (NVIDIA) wrote:
>> The macro is only used by i915. Move it to a local header and drop from
>> the kernel.h.
> 
> Agree, if one wants to reinstate it, there should be better place for it
> (something related to kasan?).

or <linux/poison.h>

> FWIW,
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Acked-by: Randy Dunlap <rdunlap@infradead.org>

-- 
~Randy