Commit e48a8699 authored by Miroslav Lichvar's avatar Miroslav Lichvar Committed by Thomas Gleixner
Browse files

timekeeping: Fix timex status validation for auxiliary clocks 



The timekeeping_validate_timex() function validates the timex status
of an auxiliary system clock even when the status is not to be changed,
which causes unexpected errors for applications that make read-only
clock_adjtime() calls, or set some other timex fields, but without
clearing the status field.

Do the AUX-specific status validation only when the modes field contains
ADJ_STATUS, i.e. the application is actually trying to change the
status. This makes the AUX-specific clock_adjtime() behavior consistent
with CLOCK_REALTIME.

Fixes: 4eca49d0 ("timekeeping: Prepare do_adtimex() for auxiliary clocks")
Signed-off-by: default avatarMiroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260225085231.276751-1-mlichvar@redhat.com
parent 11439c46

kernel/time/timekeeping.c

+4 −2
Original line number Diff line number Diff line
@@ -2653,7 +2653,8 @@ static int timekeeping_validate_timex(const struct __kernel_timex *txc, bool aux 


	if (aux_clock) {

		/* Auxiliary clocks are similar to TAI and do not have leap seconds */

		if (txc->status & (STA_INS | STA_DEL))

		if (txc->modes & ADJ_STATUS &&

		    txc->status & (STA_INS | STA_DEL))

			return -EINVAL;



		/* No TAI offset setting */
@@ -2661,7 +2662,8 @@ static int timekeeping_validate_timex(const struct __kernel_timex *txc, bool aux 
			return -EINVAL;



		/* No PPS support either */

		if (txc->status & (STA_PPSFREQ | STA_PPSTIME))

		if (txc->modes & ADJ_STATUS &&

		    txc->status & (STA_PPSFREQ | STA_PPSTIME))

			return -EINVAL;

	}