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authorThomas Gleixner <tglx@linutronix.de>2021-04-22 21:44:22 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-06-22 16:42:08 +0200
commite112c41341c03d9224a9fc522bdb3539bc849b56 (patch)
treeebdf35aeef76543b9af96ebd50848d2833dd89cf /kernel/futex.c
parent1a8122960484b19d8d887fb32e1cf42be5647533 (diff)
futex: Prepare futex_lock_pi() for runtime clock selection
futex_lock_pi() is the only futex operation which cannot select the clock for timeouts (CLOCK_MONOTONIC/CLOCK_REALTIME). That's inconsistent and there is no particular reason why this cannot be supported. This was overlooked when CLOCK_REALTIME_FLAG was introduced and unfortunately not reported when the inconsistency was discovered in glibc. Prepare the function and enforce the CLOCK_REALTIME_FLAG on FUTEX_LOCK_PI so that a new FUTEX_LOCK_PI2 can implement it correctly. Reported-by: Kurt Kanzenbach <kurt@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210422194705.338657741@linutronix.de
Diffstat (limited to 'kernel/futex.c')
-rw-r--r--kernel/futex.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 08008c225bec..f820439a8aae 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2783,7 +2783,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
if (refill_pi_state_cache())
return -ENOMEM;
- to = futex_setup_timer(time, &timeout, FLAGS_CLOCKRT, 0);
+ to = futex_setup_timer(time, &timeout, flags, 0);
retry:
ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, FUTEX_WRITE);
@@ -3739,6 +3739,7 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
case FUTEX_WAKE_OP:
return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
case FUTEX_LOCK_PI:
+ flags |= FLAGS_CLOCKRT;
return futex_lock_pi(uaddr, flags, timeout, 0);
case FUTEX_UNLOCK_PI:
return futex_unlock_pi(uaddr, flags);