diff options
| author | Juergen Gross <jgross@suse.com> | 2021-06-23 15:09:13 +0200 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2021-06-24 12:52:36 +0200 |
| commit | 3de218ff39b9e3f0d453fe3154f12a174de44b25 (patch) | |
| tree | 992878585c4a8ec453556fa77989796fe510849d /drivers | |
| parent | xen-netback: take a reference to the RX task thread (diff) | |
| download | linux-3de218ff39b9e3f0d453fe3154f12a174de44b25.tar.xz linux-3de218ff39b9e3f0d453fe3154f12a174de44b25.zip | |
xen/events: reset active flag for lateeoi events later
In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.
This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.
Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/xen/events/events_base.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 7bbfd58958bc..d7e361fb0548 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -642,6 +642,9 @@ static void xen_irq_lateeoi_locked(struct irq_info *info, bool spurious) } info->eoi_time = 0; + + /* is_active hasn't been reset yet, do it now. */ + smp_store_release(&info->is_active, 0); do_unmask(info, EVT_MASK_REASON_EOI_PENDING); } @@ -811,6 +814,7 @@ static void xen_evtchn_close(evtchn_port_t port) BUG(); } +/* Not called for lateeoi events. */ static void event_handler_exit(struct irq_info *info) { smp_store_release(&info->is_active, 0); @@ -1883,7 +1887,12 @@ static void lateeoi_ack_dynirq(struct irq_data *data) if (VALID_EVTCHN(evtchn)) { do_mask(info, EVT_MASK_REASON_EOI_PENDING); - event_handler_exit(info); + /* + * Don't call event_handler_exit(). + * Need to keep is_active non-zero in order to ignore re-raised + * events after cpu affinity changes while a lateeoi is pending. + */ + clear_evtchn(evtchn); } } |