FAILED: patch "[PATCH] x86/init: Initialize wall clock in get_rtc_noop()" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] x86/init: Initialize wall clock in get_rtc_noop()" failed to apply to 5.15-stable tree

[Sasha Levin]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 7d5af1f256fdecff6a7986bbc9146b69cb355bb5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261109202235-failed-5.15-7d5af1f256fd@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 7d5af1f256fdecff6a7986bbc9146b69cb355bb5 Mon Sep 17 00:00:00 2001
From: Naman Jain <namjain@linux.microsoft.com>
Date: Mon, 31 Aug 2026 08:25:28 +0000
Subject: [PATCH] x86/init: Initialize wall clock in get_rtc_noop()

get_rtc_noop() is used when an RTC is unavailable, but leaves its output
argument untouched. When CONFIG_INIT_STACK_ALL_ZERO is not enabled,
timekeeping_init() may therefore receive a nonzero invalid persistent
clock value and warn:

  "Persistent clock returned invalid value"

Initialize the output to zero, the documented representation of an
unsupported persistent clock.

Fixes: c311ed6183f4 ("x86/init: Allow DT configured systems to disable RTC at boot time")
Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Roman Kisel <vdso@mailbox.org>
Reviewed-by: Hardik Garg <hargar@linux.microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260831082528.1623843-1-namjain@linux.microsoft.com
---
 arch/x86/kernel/x86_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index 252c5827d0634..3b9b41820c84c 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -37,7 +37,7 @@ static void iommu_shutdown_noop(void) { }
 bool __init bool_x86_init_noop(void) { return false; }
 void x86_op_int_noop(int cpu) { }
 int set_rtc_noop(const struct timespec64 *now) { return -EINVAL; }
-void get_rtc_noop(struct timespec64 *now) { }
+void get_rtc_noop(struct timespec64 *now) { *now = (struct timespec64){0}; }
 
 static __initconst const struct of_device_id of_cmos_match[] = {
 	{ .compatible = "motorola,mc146818" },
-- 
2.53.0

[PATCH 5.15.y] x86/init: Initialize wall clock in get_rtc_noop()

[Naman Jain]

get_rtc_noop() is used when an RTC is unavailable, but leaves its output
argument untouched. When CONFIG_INIT_STACK_ALL_ZERO is not enabled,
timekeeping_init() may therefore receive a nonzero invalid persistent
clock value and warn:

  "Persistent clock returned invalid value"

Initialize the output to zero, the documented representation of an
unsupported persistent clock.

Fixes: c311ed6183f4 ("x86/init: Allow DT configured systems to disable RTC at boot time")
Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Roman Kisel <vdso@mailbox.org>
Reviewed-by: Hardik Garg <hargar@linux.microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260831082528.1623843-1-namjain@linux.microsoft.com
(cherry picked from commit 7d5af1f256fdecff6a7986bbc9146b69cb355bb5)
---
 arch/x86/kernel/x86_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index d3e3b16ea9cf3..ef8c7f975f7ad 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -33,7 +33,7 @@ static void iommu_shutdown_noop(void) { }
 bool __init bool_x86_init_noop(void) { return false; }
 void x86_op_int_noop(int cpu) { }
 static int set_rtc_noop(const struct timespec64 *now) { return -EINVAL; }
-static void get_rtc_noop(struct timespec64 *now) { }
+static void get_rtc_noop(struct timespec64 *now) { *now = (struct timespec64){0}; }
 
 static __initconst const struct of_device_id of_cmos_match[] = {
 	{ .compatible = "motorola,mc146818" },
-- 
2.43.0