[PATCH 6.18 079/227] timekeeping: Adjust the leap state for the correct auxiliary timekeeper

Greg Kroah-Hartman
2026-01-28T15:54:29Z

From: Thomas Weißschuh <thomas.weissschuh@linutronix.de>

commit e806f7dde8ba28bc72a7a0898589cac79f6362ac upstream.

When __do_ajdtimex() was introduced to handle adjtimex for any
timekeeper, this reference to tk_core was not updated. When called on an
auxiliary timekeeper, the core timekeeper would be updated incorrectly.

This gets caught by the lock debugging diagnostics because the
timekeepers sequence lock gets written to without holding its
associated spinlock:

WARNING: include/linux/seqlock.h:226 at __do_adjtimex+0x394/0x3b0, CPU#2: test/125
aux_clock_adj (kernel/time/timekeeping.c:2979)
__do_sys_clock_adjtime (kernel/time/posix-timers.c:1161 kernel/time/posix-timers.c:1173)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)

Update the correct auxiliary timekeeper.

Fixes: 775f71ebedd3 ("timekeeping: Make do_adjtimex() reusable")
Fixes: ecf3e7030491 ("timekeeping: Provide adjtimex() for auxiliary clocks")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260120-timekeeper-auxclock-leapstate-v1-1-5b358c6b3cfd@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/time/timekeeping.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -2721,7 +2721,7 @@ static int __do_adjtimex(struct tk_data
timekeeping_update_from_shadow(tkd, TK_CLOCK_WAS_SET);
result->clock_set = true;
} else {
- tk_update_leap_state_all(&tk_core);
+ tk_update_leap_state_all(tkd);
}

/* Update the multiplier immediately if frequency was set directly */