diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2021-04-22 21:44:22 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-06-22 16:42:08 +0200 |
| commit | e112c41341c03d9224a9fc522bdb3539bc849b56 (patch) | |
| tree | ebdf35aeef76543b9af96ebd50848d2833dd89cf | |
| parent | 1a8122960484b19d8d887fb32e1cf42be5647533 (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
| -rw-r--r-- | kernel/futex.c | 3 |
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); |