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Groups > linux.kernel > #1494364
| From | Thomas Gleixner <tglx@linutronix.de> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 07/13] futex: Throughput-optimized (TP) futexes |
| Date | 2016-10-01 09:00 +0200 |
| Message-ID | <snmr7-4JK-3@gated-at.bofh.it> (permalink) |
| References | <sndxv-7oR-7@gated-at.bofh.it> <sndHb-7ss-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, 30 Sep 2016, Waiman Long wrote:
> + WRITE_ONCE(state->owner, current);
> + preempt_disable();
> + for (;;) {
> + ret = futex_trylock(uaddr, vpid, &uval, true);
Did you actually read what I said? You CANNOT access userspace in a preempt
disabled region without disabling pagefaults and handle the resulting
wreckage yourself.
End of review.
tglx
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[PATCH v3 00/13] futex: Introducing throughput-optimized futexes Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:30 +0200
[PATCH v3 02/13] futex: Rename futex_pi_state to futex_state Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:30 +0200
[PATCH v3 13/13] perf bench: New microbenchmark for userspace mutex performance Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:30 +0200
[PATCH v3 04/13] futex: Consolidate pure pi_state_list add & delete codes to helpers Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:40 +0200
[PATCH v3 06/13] futex: Allow direct attachment of futex_state objects to hash bucket Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:40 +0200
[PATCH v3 07/13] futex: Throughput-optimized (TP) futexes Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:40 +0200
Re: [PATCH v3 07/13] futex: Throughput-optimized (TP) futexes Thomas Gleixner <tglx@linutronix.de> - 2016-10-01 09:00 +0200
[PATCH v3 10/13] futex: Inform FUTEX_LOCK callers on how the lock is acquired Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:40 +0200
[PATCH v3 11/13] futex: Add timeout support to TP futexes Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:40 +0200
[PATCH v3 05/13] futex: Add a new futex type field into futex_state Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:40 +0200
[PATCH v3 08/13] futex: Enable robust handling of TP futexes Waiman Long <Waiman.Long@hpe.com> - 2016-09-30 23:40 +0200
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