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| author | Juri Lelli <juri.lelli@redhat.com> | 2022-06-27 12:50:51 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-17 16:14:06 +0300 |
| commit | 74e1beed470405d9e293a2760f54a00c15cf39c7 (patch) | |
| tree | 1d7ec5b1e021a479a0bb6c6c7fe39997e01c40ee | |
| parent | 46cc4c076ac289a6a6702f99af94f67801ee08ab (diff) | |
| download | linux-74e1beed470405d9e293a2760f54a00c15cf39c7.tar.xz | |
wait: Fix __wait_event_hrtimeout for RT/DL tasks
[ Upstream commit cceeeb6a6d02e7b9a74ddd27a3225013b34174aa ]
Changes to hrtimer mode (potentially made by __hrtimer_init_sleeper on
PREEMPT_RT) are not visible to hrtimer_start_range_ns, thus not
accounted for by hrtimer_start_expires call paths. In particular,
__wait_event_hrtimeout suffers from this problem as we have, for
example:
fs/aio.c::read_events
wait_event_interruptible_hrtimeout
__wait_event_hrtimeout
hrtimer_init_sleeper_on_stack <- this might "mode |= HRTIMER_MODE_HARD"
on RT if task runs at RT/DL priority
hrtimer_start_range_ns
WARN_ON_ONCE(!(mode & HRTIMER_MODE_HARD) ^ !timer->is_hard)
fires since the latter doesn't see the change of mode done by
init_sleeper
Fix it by making __wait_event_hrtimeout call hrtimer_sleeper_start_expires,
which is aware of the special RT/DL case, instead of hrtimer_start_range_ns.
Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20220627095051.42470-1-juri.lelli@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | include/linux/wait.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h index 851e07da2583..58cfbf81447c 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -544,10 +544,11 @@ do { \ \ hrtimer_init_sleeper_on_stack(&__t, CLOCK_MONOTONIC, \ HRTIMER_MODE_REL); \ - if ((timeout) != KTIME_MAX) \ - hrtimer_start_range_ns(&__t.timer, timeout, \ - current->timer_slack_ns, \ - HRTIMER_MODE_REL); \ + if ((timeout) != KTIME_MAX) { \ + hrtimer_set_expires_range_ns(&__t.timer, timeout, \ + current->timer_slack_ns); \ + hrtimer_sleeper_start_expires(&__t, HRTIMER_MODE_REL); \ + } \ \ __ret = ___wait_event(wq_head, condition, state, 0, 0, \ if (!__t.task) { \ |