[v13,16/24] selftests/vm: clear the bits in shadow reg when a pkey is freed.

Message ID 1528937115-10132-17-git-send-email-linuxram@us.ibm.com
State New
Headers show
Series
  • selftests, powerpc, x86 : Memory Protection Keys
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Commit Message

Ram Pai June 14, 2018, 12:45 a.m.
When a key is freed, the  key  is  no  more  effective.
Clear the bits corresponding to the pkey in the shadow
register. Otherwise  it  will carry some spurious bits
which can trigger false-positive asserts.

cc: Dave Hansen <dave.hansen@intel.com>
cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
 tools/testing/selftests/vm/protection_keys.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

Comments

Dave Hansen June 20, 2018, 3:07 p.m. | #1
On 06/13/2018 05:45 PM, Ram Pai wrote:
> --- a/tools/testing/selftests/vm/protection_keys.c
> +++ b/tools/testing/selftests/vm/protection_keys.c
> @@ -577,7 +577,8 @@ int sys_pkey_free(unsigned long pkey)
>  	int ret = syscall(SYS_pkey_free, pkey);
>  
>  	if (!ret)
> -		shadow_pkey_reg &= clear_pkey_flags(pkey, PKEY_DISABLE_ACCESS);
> +		shadow_pkey_reg &= clear_pkey_flags(pkey,
> +				PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE);
>  	dprintf1("%s(pkey=%ld) syscall ret: %d\n", __func__, pkey, ret);
>  	return ret;
>  }

Why did you introduce this code earlier and then modify it now?

BTW, my original aversion to this code still stands.

Patch

diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index 88dfa40..ba184ca 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -577,7 +577,8 @@  int sys_pkey_free(unsigned long pkey)
 	int ret = syscall(SYS_pkey_free, pkey);
 
 	if (!ret)
-		shadow_pkey_reg &= clear_pkey_flags(pkey, PKEY_DISABLE_ACCESS);
+		shadow_pkey_reg &= clear_pkey_flags(pkey,
+				PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE);
 	dprintf1("%s(pkey=%ld) syscall ret: %d\n", __func__, pkey, ret);
 	return ret;
 }