[v1] x86/traps: Print unhashed pointers on stack overflow

[PATCH] x86/traps: Print unhashed pointers on stack overflow

Posted by Ryosuke Yasuoka 1 month, 2 weeks ago

When a stack overflow occurs, the kernel prints hashed fault address and
the stack range using %p. The actual addresses are required for
debugging and hashed pointers provide no useful information in this
context.

Use %px to print the unhashed, raw addresses.

Signed-off-by: Ryosuke Yasuoka <ryasuoka@redhat.com>
---
 arch/x86/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index bcf1dedc1d00..5a6a772e0a6c 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -549,7 +549,7 @@ __visible void __noreturn handle_stack_overflow(struct pt_regs *regs,
 {
 	const char *name = stack_type_name(info->type);
 
-	printk(KERN_EMERG "BUG: %s stack guard page was hit at %p (stack is %p..%p)\n",
+	printk(KERN_EMERG "BUG: %s stack guard page was hit at %px (stack is %px..%px)\n",
 	       name, (void *)fault_address, info->begin, info->end);
 
 	die("stack guard page", regs, 0);

base-commit: b927546677c876e26eba308550207c2ddf812a43
-- 
2.52.0

Re: [PATCH] x86/traps: Print unhashed pointers on stack overflow

Posted by Ryosuke Yasuoka 3 weeks, 4 days ago

On Wed, Dec 24, 2025 at 04:07:32PM +0900, Ryosuke Yasuoka wrote:
> When a stack overflow occurs, the kernel prints hashed fault address and
> the stack range using %p. The actual addresses are required for
> debugging and hashed pointers provide no useful information in this
> context.
> 
> Use %px to print the unhashed, raw addresses.
> 
> Signed-off-by: Ryosuke Yasuoka <ryasuoka@redhat.com>
> ---
>  arch/x86/kernel/traps.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index bcf1dedc1d00..5a6a772e0a6c 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -549,7 +549,7 @@ __visible void __noreturn handle_stack_overflow(struct pt_regs *regs,
>  {
>  	const char *name = stack_type_name(info->type);
>  
> -	printk(KERN_EMERG "BUG: %s stack guard page was hit at %p (stack is %p..%p)\n",
> +	printk(KERN_EMERG "BUG: %s stack guard page was hit at %px (stack is %px..%px)\n",
>  	       name, (void *)fault_address, info->begin, info->end);
>  
>  	die("stack guard page", regs, 0);
> 
> base-commit: b927546677c876e26eba308550207c2ddf812a43
> -- 
> 2.52.0
> 

Hi all,

It's just a gentle ping on this patch.

Please let me know if there are any changes required. Any feedbacks are
welcome.

Thank you
Ryosuke

[tip: x86/misc] x86/traps: Print unhashed pointers on stack overflow

Posted by tip-bot2 for Ryosuke Yasuoka 3 weeks, 3 days ago

The following commit has been merged into the x86/misc branch of tip:

Commit-ID:     6b32c93560cb194e10279bd3be3c1d0fa30df3e7
Gitweb:        https://git.kernel.org/tip/6b32c93560cb194e10279bd3be3c1d0fa30df3e7
Author:        Ryosuke Yasuoka <ryasuoka@redhat.com>
AuthorDate:    Wed, 24 Dec 2025 16:07:32 +09:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Wed, 14 Jan 2026 16:31:53 +01:00

x86/traps: Print unhashed pointers on stack overflow

When a stack overflow occurs, the kernel prints hashed fault address and the
stack range using %p. The actual addresses are required for debugging and
hashed pointers provide no useful information in this context.

Use %px to print the unhashed, raw addresses.

Signed-off-by: Ryosuke Yasuoka <ryasuoka@redhat.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20251224070735.454816-1-ryasuoka@redhat.com
---
 arch/x86/kernel/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index bcf1ded..5a6a772 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -549,7 +549,7 @@ __visible void __noreturn handle_stack_overflow(struct pt_regs *regs,
 {
 	const char *name = stack_type_name(info->type);
 
-	printk(KERN_EMERG "BUG: %s stack guard page was hit at %p (stack is %p..%p)\n",
+	printk(KERN_EMERG "BUG: %s stack guard page was hit at %px (stack is %px..%px)\n",
 	       name, (void *)fault_address, info->begin, info->end);
 
 	die("stack guard page", regs, 0);