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IB/IPoIB: Avoid restoring OPER_UP after multicast flush

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ipoib_ib_dev_flush_light() temporarily clears IPOIB_FLAG_OPER_UP to
prevent multicast joins while ipoib_mcast_dev_flush() is running, and
restores the flag afterwards if it was previously set.

This restore races with ipoib_ib_dev_down(). If the interface is brought
down while the flush is in progress, ipoib_ib_dev_down() clears
IPOIB_FLAG_OPER_UP, but the flush path may set it again after the device
has already gone down.

Since commit 894021a752 ("IB/ipoib: Make the carrier_on_task race
aware"), ipoib_mcast_carrier_on_task() relies on IPOIB_FLAG_OPER_UP
being cleared to terminate its rtnl_trylock() retry loop. If the flag is
left set after shutdown, the workqueue retries forever, causing teardown
to deadlock when ipoib_ndo_uninit() waits in destroy_workqueue() while
holding RTNL.

Instead of overloading IPOIB_FLAG_OPER_UP to block multicast joins
during a light flush, introduce a dedicated IPOIB_FLAG_MCAST_FLUSH flag.
Use it together with IPOIB_FLAG_OPER_UP to determine whether multicast
joins are allowed, avoiding the race with device shutdown.

Fixes: 344bacca8c ("IB/ipoib: Don't allow MC joins during light MC flush")
Reported-by: Ben Davies <ben.davies@gresearch.co.uk>
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Edward Srouji <edwards@nvidia.com>
Link: https://patch.msgid.link/20260902-avoid-rest-oper-up-v1-1-04fcd4916cae@nvidia.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
This commit is contained in:
Carolina Jubran
2026-09-06 02:38:35 -04:00
committed by Leon Romanovsky
parent 662ade4de9
commit 9a141d3dc8
3 changed files with 22 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/infiniband/ulp/ipoib/ipoib.h
+7
View File
@@ -87,6 +87,7 @@ enum {
IPOIB_FLAG_INITIALIZED = 1,
IPOIB_FLAG_ADMIN_UP = 2,
IPOIB_PKEY_ASSIGNED = 3,
IPOIB_FLAG_MCAST_FLUSH = 4,
IPOIB_FLAG_SUBINTERFACE = 5,
IPOIB_STOP_REAPER = 7,
IPOIB_FLAG_ADMIN_CM = 9,
@@ -414,6 +415,12 @@ struct ipoib_dev_priv {
const struct net_device_ops *rn_ops;
};
static inline bool ipoib_mcast_allowed(struct ipoib_dev_priv *priv)
{
return test_bit(IPOIB_FLAG_OPER_UP, &priv->flags) &&
!test_bit(IPOIB_FLAG_MCAST_FLUSH, &priv->flags);
}
struct ipoib_ah {
struct net_device *dev;
struct ib_ah *ah;
drivers/infiniband/ulp/ipoib/ipoib_ib.c
+7 -5
View File
@@ -1227,17 +1227,19 @@ static void __ipoib_ib_dev_flush(struct ipoib_dev_priv *priv,
}
if (level == IPOIB_FLUSH_LIGHT) {
int oper_up;
ipoib_mark_paths_invalid(dev);
/* Set IPoIB operation as down to prevent races between:
/* Set MCAST_FLUSH to prevent races between:
* the flush flow which leaves MCG and on the fly joins
* which can happen during that time. mcast restart task
* should deal with join requests we missed.
*
* Do not clear OPER_UP for this; restoring it races with
* ipoib_ib_dev_down() and can leave OPER_UP set after the
* device is down.
*/
oper_up = test_and_clear_bit(IPOIB_FLAG_OPER_UP, &priv->flags);
set_bit(IPOIB_FLAG_MCAST_FLUSH, &priv->flags);
ipoib_mcast_dev_flush(dev);
if (oper_up)
set_bit(IPOIB_FLAG_OPER_UP, &priv->flags);
clear_bit(IPOIB_FLAG_MCAST_FLUSH, &priv->flags);
ipoib_reap_dead_ahs(priv);
}
drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+8 -8
View File
@@ -74,7 +74,7 @@ static void __ipoib_mcast_schedule_join_thread(struct ipoib_dev_priv *priv,
struct ipoib_mcast *mcast,
bool delay)
{
if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
if (!ipoib_mcast_allowed(priv))
return;
/*
@@ -469,7 +469,7 @@ static int ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast)
int ret = 0;
if (!priv->broadcast ||
!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
!ipoib_mcast_allowed(priv))
return -EINVAL;
init_completion(&mcast->done);
@@ -555,7 +555,7 @@ void ipoib_mcast_join_task(struct work_struct *work)
unsigned long delay_until = 0;
struct ipoib_mcast *mcast = NULL;
if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
if (!ipoib_mcast_allowed(priv))
return;
if (ib_query_port(priv->ca, priv->port, &port_attr)) {
@@ -577,7 +577,7 @@ void ipoib_mcast_join_task(struct work_struct *work)
netif_addr_unlock_bh(dev);
spin_lock_irq(&priv->lock);
if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
if (!ipoib_mcast_allowed(priv))
goto out;
if (!priv->broadcast) {
@@ -749,7 +749,7 @@ void ipoib_mcast_send(struct net_device *dev, u8 *daddr, struct sk_buff *skb)
spin_lock_irqsave(&priv->lock, flags);
if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags) ||
if (!ipoib_mcast_allowed(priv) ||
!priv->broadcast ||
!test_bit(IPOIB_MCAST_FLAG_ATTACHED, &priv->broadcast->flags)) {
++dev->stats.tx_dropped;
@@ -871,7 +871,7 @@ void ipoib_mcast_restart_task(struct work_struct *work)
LIST_HEAD(remove_list);
struct ib_sa_mcmember_rec rec;
if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags))
if (!ipoib_mcast_allowed(priv))
/*
* shortcut...on shutdown flush is called next, just
* let it do all the work
@@ -965,9 +965,9 @@ void ipoib_mcast_restart_task(struct work_struct *work)
ipoib_mcast_remove_list(&remove_list);
/*
* Double check that we are still up
* Double check that we are still up and not flushing
*/
if (test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)) {
if (ipoib_mcast_allowed(priv)) {
spin_lock_irq(&priv->lock);
__ipoib_mcast_schedule_join_thread(priv, NULL, 0);
spin_unlock_irq(&priv->lock);