Add the extern declaration for panic_redirect_cpu to linux/panic.h
to fix the sparse warning:

  kernel/panic.c:305:10: sparse: sparse: symbol 'panic_redirect_cpu'
  was not declared. Should it be static?

The variable needs to be declared in the header alongside panic_cpu
since it is used for synchronization when redirecting panic to a
specific CPU via the panic_force_cpu= boot parameter.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202601161825.pUmb6FsK-lkp@intel.com/
Signed-off-by: Pnina Feder <pnina.feder@mobileye.com>
---
 include/linux/panic.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/linux/panic.h b/include/linux/panic.h
index a00bc0937698..f1dd417e54b2 100644
--- a/include/linux/panic.h
+++ b/include/linux/panic.h
@@ -41,6 +41,14 @@ void abort(void);
  * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
  */
 extern atomic_t panic_cpu;
+
+/*
+ * panic_redirect_cpu is used when panic is redirected to a specific CPU via
+ * the panic_force_cpu= boot parameter. It holds the CPU number that originally
+ * triggered the panic before redirection. A value of PANIC_CPU_INVALID means
+ * no redirection has occurred.
+ */
+extern atomic_t panic_redirect_cpu;
 #define PANIC_CPU_INVALID	-1
 
 bool panic_try_start(void);
-- 
2.43.0

On Sun, 18 Jan 2026 14:01:49 +0200 Pnina Feder <pnina.feder@mobileye.com> wrote:

> Add the extern declaration for panic_redirect_cpu to linux/panic.h
> to fix the sparse warning:
> 
>   kernel/panic.c:305:10: sparse: sparse: symbol 'panic_redirect_cpu'
>   was not declared. Should it be static?
> 
> The variable needs to be declared in the header alongside panic_cpu
> since it is used for synchronization when redirecting panic to a
> specific CPU via the panic_force_cpu= boot parameter.
> 

Thanks, I added this as a squashable fix against your earlier patch
"panic: add panic_force_cpu= parameter to redirect panic to a specific
CPU".

(It's nice to tell people when a patch fixes a pending patch in this
manner - otherwise everyone has to run around trying to figure out
which tree is being patched and why).