+ selftests-proc-proc-empty-vm-handle-cpus-without-protection-keys.patch added to mm-nonmm-unstable branch

+ selftests-proc-proc-empty-vm-handle-cpus-without-protection-keys.patch added to mm-nonmm-unstable branch

[Andrew Morton]

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The patch titled
     Subject: selftests/proc: proc-empty-vm: handle CPUs without protection keys
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     selftests-proc-proc-empty-vm-handle-cpus-without-protection-keys.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-proc-proc-empty-vm-handle-cpus-without-protection-keys.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Kurt Lin <lylin1023@gmail.com>
Subject: selftests/proc: proc-empty-vm: handle CPUs without protection keys
Date: Mon,  9 Nov 2026 23:19:12 +0800

On x86 CPUs without protection keys, pkey_alloc() fails with ENOSPC,
as documented in pkey_alloc(2). protection_key_support() only expects
ENOSYS or EINVAL, so the test fails on such machines, e.g. an Intel
Core i5-7200U:

  protection_key_support: error: rv -1, errno 28

Treat ENOSPC as "no protection key support" as well.

An AI coding assistant (Claude) was used to analyze the failure and to
draft the fix and this changelog. Tested on v7.4-rc1 on the machine
above; the test now passes.

Link: https://lore.kernel.org/20261109151912.156518-1-lylin1023@gmail.com
Fixes: bf5add391eeb ("proc: test ProtectionKey in proc-empty-vm test")
Signed-off-by: Kurt Lin <lylin1023@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Swarup Laxman Kotiaklapudi <swarupkotikalapudi@gmail.com>
Cc: Carlos López <clopez@suse.de>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
---

 tools/testing/selftests/proc/proc-empty-vm.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/tools/testing/selftests/proc/proc-empty-vm.c~selftests-proc-proc-empty-vm-handle-cpus-without-protection-keys
+++ a/tools/testing/selftests/proc/proc-empty-vm.c
@@ -78,6 +78,9 @@ static int protection_key_support(void)
 	} else if (rv == -1 && errno == EINVAL) {
 		// ospke=n
 		return 0;
+	} else if (rv == -1 && errno == ENOSPC) {
+		// CPU without protection keys
+		return 0;
 	} else {
 		fprintf(stderr, "%s: error: rv %ld, errno %d\n", __func__, rv, errno);
 		exit(EXIT_FAILURE);
_

Patches currently in -mm which might be from lylin1023@gmail.com are

selftests-proc-proc-empty-vm-handle-cpus-without-protection-keys.patch