The following commit has been merged into the locking/core branch of tip: Commit-ID: e112c41341c03d9224a9fc522bdb3539bc849b56 Gitweb: https://git.kernel.org/tip/e112c41341c03d9224a9fc522bdb3539bc849b56 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Thu, 22 Apr 2021 21:44:22 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Tue, 22 Jun 2021 16:42:08 +02:00 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@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210422194705.338657741@xxxxxxxxxxxxx --- kernel/futex.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/futex.c b/kernel/futex.c index 08008c2..f820439 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);
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