On Tue, Nov 03, 2020 at 07:14:07PM +0100, Greg KH wrote:

On Tue, Nov 03, 2020 at 09:53:36AM -0800, Ira Weiny wrote:

quoted

On Tue, Nov 03, 2020 at 07:50:24AM +0100, Greg KH wrote:

quoted

On Mon, Nov 02, 2020 at 12:53:15PM -0800, ira.weiny@intel.com wrote:

quoted

From: Fenghua Yu <redacted>

[snip]

quoted

quoted

diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h
index 2955ba976048..0959a4c0ca64 100644
--- a/include/linux/pkeys.h
+++ b/include/linux/pkeys.h

@@ -50,4 +50,28 @@ static inline void copy_init_pkru_to_fpregs(void)
 
 #endif /* ! CONFIG_ARCH_HAS_PKEYS */
 
+#define PKS_FLAG_EXCLUSIVE 0x00
+
+#ifndef CONFIG_ARCH_HAS_SUPERVISOR_PKEYS
+static inline int pks_key_alloc(const char * const pkey_user, int flags)
+{
+	return -EOPNOTSUPP;
+}
+static inline void pks_key_free(int pkey)
+{
+}
+static inline void pks_mk_noaccess(int pkey)
+{
+	WARN_ON_ONCE(1);

So for panic-on-warn systems, this is ok to reboot the box?

I would not expect this to reboot the box no.  But it is a violation of the API
contract.  If pky_key_alloc() returns an error calling any of the other
functions is an error.

quoted

Are you sure, that feels odd...

It does feel odd and downright wrong...  But there are a lot of WARN_ON_ONCE's
out there to catch this type of internal programming error.  Is panic-on-warn
commonly used?

Yes it is, and we are trying to recover from that as it is something
that you should recover from.  Properly handle the error and move on.

Sorry, I did not know that...  Ok I'll look at the series because I probably
have others I need to change.

Thanks,
Ira