Messages in this thread Patch in this message | | | Date | Fri, 23 Apr 2021 11:34:24 +0200 | From | Lukasz Majewski <> | Subject | Re: [patch 5/6] futex: Prepare futex_lock_pi() for runtime clock selection |
| |
Hi Thomas,
> 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> > --- > kernel/futex.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -2786,7 +2786,7 @@ static int futex_lock_pi(u32 __user *uad > 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); @@ -3711,7 +3711,7 @@ long do_futex(u32 __user *uaddr, > int op, > if (op & FUTEX_CLOCK_REALTIME) { > flags |= FLAGS_CLOCKRT; > - if (cmd != FUTEX_WAIT_BITSET && cmd != > FUTEX_WAIT_REQUEUE_PI) > + if (cmd != FUTEX_WAIT_BITSET && cmd != > FUTEX_WAIT_REQUEUE_PI) return -ENOSYS;
What is the exact change for those two lines above? Looks like some different tab/spaces...
> } > > @@ -3743,6 +3743,7 @@ long do_futex(u32 __user *uaddr, int op, > 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); >
Best regards,
Lukasz Majewski
-- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de [unhandled content-type:application/pgp-signature] | |