wait: Fix __wait_event_hrtimeout for RT/DL tasks
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
Please register or sign in to comment