Commit cdf78db4 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI 



FUTEX_LOCK_PI does not require to have the FUTEX_CLOCK_REALTIME bit set
because it has been using CLOCK_REALTIME based absolute timeouts
forever. Due to that, the time namespace adjustment which is applied when
FUTEX_CLOCK_REALTIME is not set, will wrongly take place for FUTEX_LOCK_PI
and wreckage the timeout.

Exclude it from that procedure.

Fixes: c2f7d08c ("futex: Adjust absolute futex timeouts with per time namespace offset")
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210422194704.984540159@linutronix.de
parent 4fbf5d68

kernel/futex.c

+2 −2
Original line number Diff line number Diff line
@@ -3780,7 +3780,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, 
		t = timespec64_to_ktime(ts);

		if (cmd == FUTEX_WAIT)

			t = ktime_add_safe(ktime_get(), t);

		else if (!(op & FUTEX_CLOCK_REALTIME))

		else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))

			t = timens_ktime_to_host(CLOCK_MONOTONIC, t);

		tp = &t;

	}
@@ -3974,7 +3974,7 @@ SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val, 
		t = timespec64_to_ktime(ts);

		if (cmd == FUTEX_WAIT)

			t = ktime_add_safe(ktime_get(), t);

		else if (!(op & FUTEX_CLOCK_REALTIME))

		else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))

			t = timens_ktime_to_host(CLOCK_MONOTONIC, t);

		tp = &t;

	}