From: Jiri Pirko Date: Tue, 27 Jan 2026 09:38:39 +0000 (+0100) Subject: RDMA/core: Fix stale RoCE GIDs during netdev events at registration X-Git-Tag: v7.0-rc2~35^2~10 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9af0feae8016ba58ad7ff784a903404986b395b1;p=thirdparty%2Fkernel%2Flinux.git RDMA/core: Fix stale RoCE GIDs during netdev events at registration RoCE GID entries become stale when netdev properties change during the IB device registration window. This is reproducible with a udev rule that sets a MAC address when a VF netdev appears: ACTION=="add", SUBSYSTEM=="net", KERNEL=="eth4", \ RUN+="/sbin/ip link set eth4 address 88:22:33:44:55:66" After VF creation, show_gids displays GIDs derived from the original random MAC rather than the configured one. The root cause is a race between netdev event processing and device registration: CPU 0 (driver) CPU 1 (udev/workqueue) ────────────── ────────────────────── ib_register_device() ib_cache_setup_one() gid_table_setup_one() _gid_table_setup_one() ← GID table allocated rdma_roce_rescan_device() ← GIDs populated with OLD MAC ip link set eth4 addr NEW_MAC NETDEV_CHANGEADDR queued netdevice_event_work_handler() ib_enum_all_roce_netdevs() ← Iterates DEVICE_REGISTERED ← Device NOT marked yet, SKIP! enable_device_and_get() xa_set_mark(DEVICE_REGISTERED) ← Too late, event was lost The netdev event handler uses ib_enum_all_roce_netdevs() which only iterates devices marked DEVICE_REGISTERED. However, this mark is set late in the registration process, after the GID cache is already populated. Events arriving in this window are silently dropped. Fix this by introducing a new xarray mark DEVICE_GID_UPDATES that is set immediately after the GID table is allocated and initialized. Use the new mark in ib_enum_all_roce_netdevs() function to iterate devices instead of DEVICE_REGISTERED. This is safe because: - After _gid_table_setup_one(), all required structures exist (port_data, immutable, cache.gid) - The GID table mutex serializes concurrent access between the initial rescan and event handlers - Event handlers correctly update stale GIDs even when racing with rescan - The mark is cleared in ib_cache_cleanup_one() before teardown This also fixes similar races for IP address events (inetaddr_event, inet6addr_event) which use the same enumeration path. Fixes: 0df91bb67334 ("RDMA/devices: Use xarray to store the client_data") Signed-off-by: Jiri Pirko Link: https://patch.msgid.link/20260127093839.126291-1-jiri@resnulli.us Reported-by: syzbot+881d65229ca4f9ae8c84@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84 Signed-off-by: Leon Romanovsky --- diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c index b415d4aad04f..ee4a2bc68fb2 100644 --- a/drivers/infiniband/core/cache.c +++ b/drivers/infiniband/core/cache.c @@ -926,6 +926,13 @@ static int gid_table_setup_one(struct ib_device *ib_dev) if (err) return err; + /* + * Mark the device as ready for GID cache updates. This allows netdev + * event handlers to update the GID cache even before the device is + * fully registered. + */ + ib_device_enable_gid_updates(ib_dev); + rdma_roce_rescan_device(ib_dev); return err; @@ -1637,6 +1644,12 @@ void ib_cache_release_one(struct ib_device *device) void ib_cache_cleanup_one(struct ib_device *device) { + /* + * Clear the GID updates mark first to prevent event handlers from + * accessing the device while it's being torn down. + */ + ib_device_disable_gid_updates(device); + /* The cleanup function waits for all in-progress workqueue * elements and cleans up the GID cache. This function should be * called after the device was removed from the devices list and diff --git a/drivers/infiniband/core/core_priv.h b/drivers/infiniband/core/core_priv.h index 05102769a918..a2c36666e6fc 100644 --- a/drivers/infiniband/core/core_priv.h +++ b/drivers/infiniband/core/core_priv.h @@ -100,6 +100,9 @@ void ib_enum_all_roce_netdevs(roce_netdev_filter filter, roce_netdev_callback cb, void *cookie); +void ib_device_enable_gid_updates(struct ib_device *device); +void ib_device_disable_gid_updates(struct ib_device *device); + typedef int (*nldev_callback)(struct ib_device *device, struct sk_buff *skb, struct netlink_callback *cb, diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index 1b5f1ee0a557..558b73940d66 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -93,6 +93,7 @@ static struct workqueue_struct *ib_unreg_wq; static DEFINE_XARRAY_FLAGS(devices, XA_FLAGS_ALLOC); static DECLARE_RWSEM(devices_rwsem); #define DEVICE_REGISTERED XA_MARK_1 +#define DEVICE_GID_UPDATES XA_MARK_2 static u32 highest_client_id; #define CLIENT_REGISTERED XA_MARK_1 @@ -2412,11 +2413,42 @@ void ib_enum_all_roce_netdevs(roce_netdev_filter filter, unsigned long index; down_read(&devices_rwsem); - xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) + xa_for_each_marked(&devices, index, dev, DEVICE_GID_UPDATES) ib_enum_roce_netdev(dev, filter, filter_cookie, cb, cookie); up_read(&devices_rwsem); } +/** + * ib_device_enable_gid_updates - Mark device as ready for GID cache updates + * @device: Device to mark + * + * Called after GID table is allocated and initialized. After this mark is set, + * netdevice event handlers can update the device's GID cache. This allows + * events that arrive during device registration to be processed, avoiding + * stale GID entries when netdev properties change during the device + * registration process. + */ +void ib_device_enable_gid_updates(struct ib_device *device) +{ + down_write(&devices_rwsem); + xa_set_mark(&devices, device->index, DEVICE_GID_UPDATES); + up_write(&devices_rwsem); +} + +/** + * ib_device_disable_gid_updates - Clear the GID updates mark + * @device: Device to unmark + * + * Called before GID table cleanup to prevent event handlers from accessing + * the device while it's being torn down. + */ +void ib_device_disable_gid_updates(struct ib_device *device) +{ + down_write(&devices_rwsem); + xa_clear_mark(&devices, device->index, DEVICE_GID_UPDATES); + up_write(&devices_rwsem); +} + /* * ib_enum_all_devs - enumerate all ib_devices * @cb: Callback to call for each found ib_device