linux.git/include/net/netdev_lock.h, branch v7.2-rc1

net: ethtool: make dev->hwprov ops-protected

2026-06-09T17:13:04+00:00

dev->hwprov tracks the active hwtstamp provider for the device.
Make it ops protected (instance lock if the netdev driver opts
into holding instance lock around callbacks, otherwise rtnl_lock).

hwprov is written and read in:
 - drivers/net/phy/phy_device.c
    phydev and ops protection don't currently mix, add a comment
 - net/ethtool/
    as of now holds both rtnl lock and ops lock, this one will
    soon only hold one lock or the other

read in:
 - net/core/dev_ioctl.c
    holds both rtnl lock and ops lock
 - net/core/timestamping.c
    RCU reader

The new netdev_ops_lock_dereference() helper does not have
"compat" in the name. The name would be quite long and I think
in this case it should be obvious that we need _a_ lock.
netdev_lock_dereference() already exists and means dev->lock
is always expected.

Reviewed-by: Eric Dumazet 
Acked-by: Stanislav Fomichev 
Reviewed-by: Jacob Keller 
Link: https://patch.msgid.link/20260605002912.3456868-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: ethtool: cmis_cdb: hold instance lock for ops locked devices

2026-06-04T21:04:55+00:00

FW module flashing was written so that the flashing happens
without holding rtnl_lock. This allows flashing multiple modules
at once. Current drivers can handle that well, but we should
let drivers depend on the netdev instance lock. Instance lock
is per netdev, and so is the module so we won't break parallel
updates.

Reviewed-by: Jakub Sitnicki 
Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260603012840.2254293-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: rename netdev_ops_assert_locked()

2026-06-04T21:04:55+00:00

Jakub suggests renaming the existing assert to match
the netdev_lock_ops_compat() semantics.

We want netdev_assert_locked_ops() to mean - if the driver
is ops locked - check that it's holding the device lock.

The existing helper check for either ops lock or rtnl_lock,
which is the locking behavior of netdev_lock_ops_compat().

The reason for naming divergence is likely that
netdev_ops_assert_locked() predated the _compat() helpers.

Suggested-by: Jakub Sitnicki 
Reviewed-by: Nicolai Buchwitz 
Reviewed-by: Jakub Sitnicki 
Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260603012840.2254293-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-05-22T16:42:41+00:00

Cross-merge networking fixes after downstream PR (net-6.15-rc8).

Conflicts:
  80f2ab46c2ee ("irdma: free iwdev->rf after removing MSI-X")
  4bcc063939a5 ("ice, irdma: fix an off by one in error handling code")
  c24a65b6a27c ("iidc/ice/irdma: Update IDC to support multiple consumers")
https://lore.kernel.org/20250513130630.280ee6c5@canb.auug.org.au

No extra adjacent changes.

Signed-off-by: Jakub Kicinski

bnxt_en: Fix netdev locking in ULP IRQ functions

2025-05-21T01:52:11+00:00

netdev_lock is already held when calling bnxt_ulp_irq_stop() and
bnxt_ulp_irq_restart().  When converting rtnl_lock to netdev_lock,
the original code was rtnl_dereference() to indicate that rtnl_lock
was already held.  rcu_dereference_protected() is the correct
conversion after replacing rtnl_lock with netdev_lock.

Add a new helper netdev_lock_dereference() similar to
rtnl_dereference().

Fixes: 004b5008016a ("eth: bnxt: remove most dependencies on RTNL")
Reviewed-by: Andy Gospodarek 
Reviewed-by: Pavan Chebbi 
Signed-off-by: Michael Chan 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250519204130.3097027-2-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski

net: let lockdep compare instance locks

2025-05-21T01:14:33+00:00

AFAIU always returning -1 from lockdep's compare function
basically disables checking of dependencies between given
locks. Try to be a little more precise about what guarantees
that instance locks won't deadlock.

Right now we only nest them under protection of rtnl_lock.
Mostly in unregister_netdevice_many() and dev_close_many().

Acked-by: Stanislav Fomichev 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250517200810.466531-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

netdev: fix the locking for netdev notifications

2025-04-18T01:55:14+00:00

Kuniyuki reports that the assert for netdev lock fires when
there are netdev event listeners (otherwise we skip the netlink
event generation).

Correct the locking when coming from the notifier.

The NETDEV_XDP_FEAT_CHANGE notifier is already fully locked,
it's the documentation that's incorrect.

Fixes: 99e44f39a8f7 ("netdev: depend on netdev->lock for xdp features")
Reported-by: syzkaller 
Reported-by: Kuniyuki Iwashima 
Link: https://lore.kernel.org/20250410171019.62128-1-kuniyu@amazon.com
Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250416030447.1077551-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

netdev: add "ops compat locking" helpers

2025-04-10T00:01:51+00:00

Add helpers to "lock a netdev in a backward-compatible way",
which for ops-locked netdevs will mean take the instance lock.
For drivers which haven't opted into the ops locking we'll take
rtnl_lock.

The scoped foreach is dropping and re-taking the lock for each
device, even if prev and next are both under rtnl_lock.
I hope that's fine since we expect that netdev nl to be mostly
supported by modern drivers, and modern drivers should also
opt into the instance locking.

Note that these helpers are mostly needed for queue related state,
because drivers modify queue config in their ops in a non-atomic
way. Or differently put, queue changes don't have a clear-cut API
like NAPI configuration. Any state that can should just use the
instance lock directly, not the "compat" hacks.

Reviewed-by: Joe Damato 
Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250408195956.412733-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski

netdevsim: add dummy device notifiers

2025-04-03T22:32:08+00:00

In order to exercise and verify notifiers' locking assumptions,
register dummy notifiers (via register_netdevice_notifier_dev_net).
Share notifier event handler that enforces the assumptions with
lock_debug.c (rename and export rtnl_net_debug_event as
netdev_debug_event). Add ops lock asserts to netdev_debug_event.

Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250401163452.622454-6-sdf@fomichev.me
Signed-off-by: Jakub Kicinski

net: designate queue -> napi linking as "ops protected"

2025-03-25T17:06:49+00:00

netdev netlink is the only reader of netdev_{,rx_}queue->napi,
and it already holds netdev->lock. Switch protection of
the writes to netdev->lock to "ops protected".

The expectation will be now that accessing queue->napi
will require netdev->lock for "ops locked" drivers, and
rtnl_lock for all other drivers.

Current "ops locked" drivers don't require any changes.
gve and netdevsim use _locked() helpers right next to
netif_queue_set_napi() so they must be holding the instance
lock. iavf doesn't call it. bnxt is a bit messy but all paths
seem locked.

Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250324224537.248800-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski