kernel/linux.git/net/bridge/br_switchdev.c, branch v7.1-rc6

bridge: Fix sleep in atomic context in sysfs path

2026-05-28T00:23:05+00:00

Since the start of the git history, brport_store() always acquired the bridge lock. Back then this decision made sense: The bridge lock protects the STP state of the bridge and its ports and at that time the function was only used by two STP related attributes (cost and priority). Nowadays, brport_store() processes a lot more attributes and most of them do not need the bridge lock: * Bridge flags: Only require RTNL. Read locklessly by the data path. Annotations can be added in net-next. * FDB port flushing: Only requires the FDB lock. * Multicast attributes: Only require the multicast lock. * Group forward mask: Only requires RTNL. Read locklessly by the data path. Annotations can be added in net-next. * Backup port: Only requires RTNL. Read locklessly by the data path. This is a problem as the bridge calls dev_set_promiscuity() when certain bridge port flags change and this function can sleep since the commit cited below, resulting in a splat such as [1]. Fix this by reducing the scope of the bridge lock and only take it when processing the two STP related attributes that require it. Remove the now stale comment from br_switchdev_set_port_flag(). The SWITCHDEV_F_DEFER flag can be removed in net-next. [1] BUG: sleeping function called from invalid context at net/core/dev_addr_lists.c:1262 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 372, name: bash preempt_count: 201, expected: 0 RCU nest depth: 0, expected: 0 5 locks held by bash/372: #0: ffff88810c51c3f0 (sb_writers#7){.+.+}-{0:0}, at: ksys_write (fs/read_write.c:740) #1: ffff888115ce9480 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter (fs/kernfs/file.c:343) #2: ffff88810b9fd330 (kn->active#37){.+.+}-{0:0}, at: kernfs_fop_write_iter (fs/kernfs/file.c:80 fs/kernfs/file.c:344) #3: ffffffffa59473a0 (rtnl_mutex){+.+.}-{4:4}, at: brport_store (net/bridge/br_sysfs_if.c:326) #4: ffff8881099d2d58 (&br->lock){+...}-{3:3}, at: brport_store (./include/linux/spinlock.h:348 net/bridge/br_sysfs_if.c:345) Preemption disabled at: 0x0 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) __might_resched.cold (kernel/sched/core.c:9163) netif_rx_mode_run (net/core/dev_addr_lists.c:1262) netif_rx_mode_sync (net/core/dev_addr_lists.c:1428) dev_set_promiscuity (net/core/dev_api.c:289) br_manage_promisc (net/bridge/br_if.c:135 net/bridge/br_if.c:172) br_port_flags_change (net/bridge/br_if.c:242 net/bridge/br_if.c:747) store_learning (net/bridge/br_sysfs_if.c:79 net/bridge/br_sysfs_if.c:235) brport_store (net/bridge/br_sysfs_if.c:346) kernfs_fop_write_iter (fs/kernfs/file.c:352) new_sync_write (fs/read_write.c:595) vfs_write (fs/read_write.c:688) ksys_write (fs/read_write.c:740) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Fixes: 78cd408356fe ("net: add missing instance lock to dev_set_promiscuity") Reviewed-by: Nikolay Aleksandrov Signed-off-by: Ido Schimmel Link: https://patch.msgid.link/20260526064818.272516-3-idosch@nvidia.com Signed-off-by: Jakub Kicinski

bridge: No DEV_PATH_BR_VLAN_UNTAG_HW for dsa foreign

2026-03-19T12:14:00+00:00

In network setup as below: fastpath bypass .----------------------------------------. / \ | IP - forwarding | | / \ v | / wan ... | / | | | | | brlan.1 | | | +-------------------------------+ | | vlan 1 | | | | | | brlan (vlan-filtering) | | | +---------------+ | | | DSA-SWITCH | | | vlan 1 | | | | to | | | | untagged 1 vlan 1 | | +---------------+---------------+ . / \ ----->wlan1 lan0 . . . ^ ^ vlan 1 tagged packets untagged packets br_vlan_fill_forward_path_mode() sets DEV_PATH_BR_VLAN_UNTAG_HW when filling in from brlan.1 towards wlan1. But it should be set to DEV_PATH_BR_VLAN_UNTAG in this case. Using BR_VLFLAG_ADDED_BY_SWITCHDEV is not correct. The dsa switchdev adds it as a foreign port. The same problem for all foreignly added dsa vlans on the bridge. First add the vlan, trying only native devices. If this fails, we know this may be a vlan from a foreign device. Use BR_VLFLAG_TAGGING_BY_SWITCHDEV to make sure DEV_PATH_BR_VLAN_UNTAG_HW is set only when there if no foreign device involved. Acked-by: Nikolay Aleksandrov Signed-off-by: Eric Woudstra Link: https://patch.msgid.link/20260317110347.363875-1-ericwouds@gmail.com Signed-off-by: Paolo Abeni

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

net: s/dev_get_port_parent_id/netif_get_port_parent_id/

2025-07-19T00:27:46+00:00

Commit cc34acd577f1 ("docs: net: document new locking reality") introduced netif_ vs dev_ function semantics: the former expects locked netdev, the latter takes care of the locking. We don't strictly follow this semantics on either side, but there are more dev_xxx handlers now that don't fit. Rename them to netif_xxx where appropriate. Signed-off-by: Stanislav Fomichev Link: https://patch.msgid.link/20250717172333.1288349-2-sdf@fomichev.me Signed-off-by: Jakub Kicinski

net: bridge: Do not offload IGMP/MLD messages

2025-07-17T14:46:41+00:00

Do not offload IGMP/MLD messages as it could lead to IGMP/MLD Reports being unintentionally flooded to Hosts. Instead, let the bridge decide where to send these IGMP/MLD messages. Consider the case where the local host is sending out reports in response to a remote querier like the following: mcast-listener-process (IP_ADD_MEMBERSHIP) \ br0 / \ swp1 swp2 | | QUERIER SOME-OTHER-HOST In the above setup, br0 will want to br_forward() reports for mcast-listener-process's group(s) via swp1 to QUERIER; but since the source hwdom is 0, the report is eligible for tx offloading, and is flooded by hardware to both swp1 and swp2, reaching SOME-OTHER-HOST as well. (Example and illustration provided by Tobias.) Fixes: 472111920f1c ("net: bridge: switchdev: allow the TX data plane forwarding to be offloaded") Signed-off-by: Joseph Huang Acked-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20250716153551.1830255-1-Joseph.Huang@garmin.com Signed-off-by: Jakub Kicinski

net: bridge: mcast: Notify on mdb offload failure

2025-04-14T22:56:43+00:00

Notify user space on mdb offload failure if mdb_offload_fail_notification is enabled. Signed-off-by: Joseph Huang Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250411150323.1117797-4-Joseph.Huang@garmin.com Signed-off-by: Jakub Kicinski

net: bridge: mcast: Add offload failed mdb flag

2025-04-14T22:56:42+00:00

Add MDB_FLAGS_OFFLOAD_FAILED and MDB_PG_FLAGS_OFFLOAD_FAILED to indicate that an attempt to offload the MDB entry to switchdev has failed. Signed-off-by: Joseph Huang Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250411150323.1117797-2-Joseph.Huang@garmin.com Signed-off-by: Jakub Kicinski

net: bridge: switchdev: Ensure deferred event delivery on unoffload

2024-02-16T09:36:37+00:00

When unoffloading a device, it is important to ensure that all relevant deferred events are delivered to it before it disassociates itself from the bridge. Before this change, this was true for the normal case when a device maps 1:1 to a net_bridge_port, i.e. br0 / swp0 When swp0 leaves br0, the call to switchdev_deferred_process() in del_nbp() makes sure to process any outstanding events while the device is still associated with the bridge. In the case when the association is indirect though, i.e. when the device is attached to the bridge via an intermediate device, like a LAG... br0 / lag0 / swp0 ...then detaching swp0 from lag0 does not cause any net_bridge_port to be deleted, so there was no guarantee that all events had been processed before the device disassociated itself from the bridge. Fix this by always synchronously processing all deferred events before signaling completion of unoffloading back to the driver. Fixes: 4e51bf44a03a ("net: bridge: move the switchdev object replay helpers to "push" mode") Signed-off-by: Tobias Waldekranz Reviewed-by: Vladimir Oltean Signed-off-by: David S. Miller

net: bridge: switchdev: Skip MDB replays of deferred events on offload

2024-02-16T09:36:37+00:00

Before this change, generation of the list of MDB events to replay would race against the creation of new group memberships, either from the IGMP/MLD snooping logic or from user configuration. While new memberships are immediately visible to walkers of br->mdb_list, the notification of their existence to switchdev event subscribers is deferred until a later point in time. So if a replay list was generated during a time that overlapped with such a window, it would also contain a replay of the not-yet-delivered event. The driver would thus receive two copies of what the bridge internally considered to be one single event. On destruction of the bridge, only a single membership deletion event was therefore sent. As a consequence of this, drivers which reference count memberships (at least DSA), would be left with orphan groups in their hardware database when the bridge was destroyed. This is only an issue when replaying additions. While deletion events may still be pending on the deferred queue, they will already have been removed from br->mdb_list, so no duplicates can be generated in that scenario. To a user this meant that old group memberships, from a bridge in which a port was previously attached, could be reanimated (in hardware) when the port joined a new bridge, without the new bridge's knowledge. For example, on an mv88e6xxx system, create a snooping bridge and immediately add a port to it: root@infix-06-0b-00:~$ ip link add dev br0 up type bridge mcast_snooping 1 && \ > ip link set dev x3 up master br0 And then destroy the bridge: root@infix-06-0b-00:~$ ip link del dev br0 root@infix-06-0b-00:~$ mvls atu ADDRESS FID STATE Q F 0 1 2 3 4 5 6 7 8 9 a DEV:0 Marvell 88E6393X 33:33:00:00:00:6a 1 static - - 0 . . . . . . . . . . 33:33:ff:87:e4:3f 1 static - - 0 . . . . . . . . . . ff:ff:ff:ff:ff:ff 1 static - - 0 1 2 3 4 5 6 7 8 9 a root@infix-06-0b-00:~$ The two IPv6 groups remain in the hardware database because the port (x3) is notified of the host's membership twice: once via the original event and once via a replay. Since only a single delete notification is sent, the count remains at 1 when the bridge is destroyed. Then add the same port (or another port belonging to the same hardware domain) to a new bridge, this time with snooping disabled: root@infix-06-0b-00:~$ ip link add dev br1 up type bridge mcast_snooping 0 && \ > ip link set dev x3 up master br1 All multicast, including the two IPv6 groups from br0, should now be flooded, according to the policy of br1. But instead the old memberships are still active in the hardware database, causing the switch to only forward traffic to those groups towards the CPU (port 0). Eliminate the race in two steps: 1. Grab the write-side lock of the MDB while generating the replay list. This prevents new memberships from showing up while we are generating the replay list. But it leaves the scenario in which a deferred event was already generated, but not delivered, before we grabbed the lock. Therefore: 2. Make sure that no deferred version of a replay event is already enqueued to the switchdev deferred queue, before adding it to the replay list, when replaying additions. Fixes: 4f2673b3a2b6 ("net: bridge: add helper to replay port and host-joined mdb entries") Signed-off-by: Tobias Waldekranz Reviewed-by: Vladimir Oltean Signed-off-by: David S. Miller

net: switchdev: Add a helper to replay objects on a bridge port

2023-07-21T07:54:03+00:00

When a front panel joins a bridge via another netdevice (typically a LAG), the driver needs to learn about the objects configured on the bridge port. When the bridge port is offloaded by the driver for the first time, this can be achieved by passing a notifier to switchdev_bridge_port_offload(). The notifier is then invoked for the individual objects (such as VLANs) configured on the bridge, and can look for the interesting ones. Calling switchdev_bridge_port_offload() when the second port joins the bridge lower is unnecessary, but the replay is still needed. To that end, add a new function, switchdev_bridge_port_replay(), which does only the replay part of the _offload() function in exactly the same way as that function. Cc: Jiri Pirko Cc: Ivan Vecera Cc: Roopa Prabhu Cc: Nikolay Aleksandrov Cc: bridge@lists.linux-foundation.org Signed-off-by: Petr Machata Reviewed-by: Danielle Ratson Signed-off-by: David S. Miller