diff mbox series

[2/5] x86/uaccess: instrument copy_from_user_nmi()

Message ID 20221102110611.1085175-2-glider@google.com
State New
Headers
Series [1/5] kmsan: core: kmsan_in_runtime() should return true in NMI context |

Commit Message

Alexander Potapenko Nov. 2, 2022, 11:06 a.m. UTC 
  Make sure usercopy hooks from linux/instrumented.h are invoked for
copy_from_user_nmi().
This fixes KMSAN false positives reported when dumping opcodes for a
stack trace.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: x86@kernel.org
Signed-off-by: Alexander Potapenko <glider@google.com>
---
 arch/x86/lib/usercopy.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Peter Zijlstra Nov. 2, 2022, 12:52 p.m. UTC | #1 
On Wed, Nov 02, 2022 at 12:06:08PM +0100, Alexander Potapenko wrote:
> Make sure usercopy hooks from linux/instrumented.h are invoked for
> copy_from_user_nmi().
> This fixes KMSAN false positives reported when dumping opcodes for a
> stack trace.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
> Cc: x86@kernel.org
> Signed-off-by: Alexander Potapenko <glider@google.com>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> ---
>  arch/x86/lib/usercopy.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
> index f1bb186171562..24b48af274173 100644
> --- a/arch/x86/lib/usercopy.c
> +++ b/arch/x86/lib/usercopy.c
> @@ -6,6 +6,7 @@
>  
>  #include <linux/uaccess.h>
>  #include <linux/export.h>
> +#include <linux/instrumented.h>
>  
>  #include <asm/tlbflush.h>
>  
> @@ -44,7 +45,9 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
>  	 * called from other contexts.
>  	 */
>  	pagefault_disable();
> +	instrument_copy_from_user_before(to, from, n);
>  	ret = raw_copy_from_user(to, from, n);
> +	instrument_copy_from_user_after(to, from, n, ret);
>  	pagefault_enable();
>  
>  	return ret;
> -- 
> 2.38.1.273.g43a17bfeac-goog
>
diff mbox series

Patch

diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
index f1bb186171562..24b48af274173 100644
--- a/arch/x86/lib/usercopy.c
+++ b/arch/x86/lib/usercopy.c
@@ -6,6 +6,7 @@ 
 
 #include <linux/uaccess.h>
 #include <linux/export.h>
+#include <linux/instrumented.h>
 
 #include <asm/tlbflush.h>
 
@@ -44,7 +45,9 @@  copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
 	 * called from other contexts.
 	 */
 	pagefault_disable();
+	instrument_copy_from_user_before(to, from, n);
 	ret = raw_copy_from_user(to, from, n);
+	instrument_copy_from_user_after(to, from, n, ret);
 	pagefault_enable();
 
 	return ret;