diff mbox series

[2/6] futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI

Message ID 20210422194704.984540159@linutronix.de
State Accepted
Commit cdf78db4070967869e4d027c11f4dd825d8f815a
Headers show
Series [1/6] Revert 337f13046ff0 ("futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op") | expand

Commit Message

Thomas Gleixner April 22, 2021, 7:44 p.m. UTC 
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: c2f7d08cccf4 ("futex: Adjust absolute futex timeouts with per time namespace offset")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: stable@vger.kernel.org
---
 kernel/futex.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3781,7 +3781,7 @@  SYSCALL_DEFINE6(futex, u32 __user *, uad
 		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;
 	}
@@ -3975,7 +3975,7 @@  SYSCALL_DEFINE6(futex_time32, u32 __user
 		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;
 	}