Re: [PATCH 2/3] tracing: Fix simple_ring_buffer undef check on parisc

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Sep 23, 2026 at 08:42:12AM +0100, Vincent Donnefort wrote:
> simple_ring_buffer uses local_set() and cmpxchg() on unsigned long. Add
> them to undefsyms_base.c to extend the allowlist for the parisc
> architecture.
> 
> Fixes: 1211907ac0b5 ("tracing: Generate undef symbols allowlist for simple_ring_buffer")
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Closes: https://lore.kernel.org/all/5574c9e6-9ed2-4ee6-a2b2-fb6ee81e83a1@roeck-us.net/
> Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

Tested-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  kernel/trace/undefsyms_base.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/undefsyms_base.c b/kernel/trace/undefsyms_base.c
> index e65baf58e6ff..37310baf706b 100644
> --- a/kernel/trace/undefsyms_base.c
> +++ b/kernel/trace/undefsyms_base.c
> @@ -9,6 +9,7 @@
>  
>  #include <linux/atomic.h>
>  #include <linux/string.h>
> +#include <asm/local.h>
>  #include <asm/page.h>
>  
>  void undefsyms_base(void *p, int n);
> @@ -18,11 +19,13 @@ static char page[PAGE_SIZE] __aligned(PAGE_SIZE);
>  void undefsyms_base(void *p, int n)
>  {
>  	char buffer[256] = { 0 };
> -
>  	u32 u = 0;
> +
>  	memset((char * volatile)page, 8, PAGE_SIZE);
>  	memset((char * volatile)buffer, 8, sizeof(buffer));
>  	memcpy((void * volatile)p, buffer, sizeof(buffer));
>  	cmpxchg((u32 * volatile)&u, 0, 8);
> +	cmpxchg((unsigned long *)p, 0, 8);
> +	local_set((local_t *)p, 8);
>  	WARN_ON(n == 0xdeadbeef);
>  }
> -- 
> 2.55.0.1082.g2b9226bbc0-goog
>