linux/net/devlink/core.c, branch v6.4

devlink: Fix crash with CONFIG_NET_NS=n

2023-05-17T02:57:52Z

'__net_initdata' becomes a no-op with CONFIG_NET_NS=y, but when this option is disabled it becomes '__initdata', which means the data can be freed after the initialization phase. This annotation is obviously incorrect for the devlink net device notifier block which is still registered after the initialization phase [1]. Fix this crash by removing the '__net_initdata' annotation. [1] general protection fault, probably for non-canonical address 0xcccccccccccccccc: 0000 [#1] PREEMPT SMP CPU: 3 PID: 117 Comm: (udev-worker) Not tainted 6.4.0-rc1-custom-gdf0acdc59b09 #64 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc37 04/01/2014 RIP: 0010:notifier_call_chain+0x58/0xc0 [...] Call Trace: dev_set_mac_address+0x85/0x120 dev_set_mac_address_user+0x30/0x50 do_setlink+0x219/0x1270 rtnl_setlink+0xf7/0x1a0 rtnetlink_rcv_msg+0x142/0x390 netlink_rcv_skb+0x58/0x100 netlink_unicast+0x188/0x270 netlink_sendmsg+0x214/0x470 __sys_sendto+0x12f/0x1a0 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x38/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: e93c9378e33f ("devlink: change per-devlink netdev notifier to static one") Reported-by: Marek Szyprowski Closes: https://lore.kernel.org/netdev/600ddf9e-589a-2aa0-7b69-a438f833ca10@samsung.com/ Tested-by: Marek Szyprowski Signed-off-by: Ido Schimmel Reviewed-by: Jiri Pirko Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230515162925.1144416-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski

devlink: change per-devlink netdev notifier to static one

2023-05-12T01:06:50Z

The commit 565b4824c39f ("devlink: change port event netdev notifier from per-net to global") changed original per-net notifier to be per-devlink instance. That fixed the issue of non-receiving events of netdev uninit if that moved to a different namespace. That worked fine in -net tree. However, later on when commit ee75f1fc44dd ("net/mlx5e: Create separate devlink instance for ethernet auxiliary device") and commit 72ed5d5624af ("net/mlx5: Suspend auxiliary devices only in case of PCI device suspend") were merged, a deadlock was introduced when removing a namespace with devlink instance with another nested instance. Here there is the bad flow example resulting in deadlock with mlx5: net_cleanup_work -> cleanup_net (takes down_read(&pernet_ops_rwsem) -> devlink_pernet_pre_exit() -> devlink_reload() -> mlx5_devlink_reload_down() -> mlx5_unload_one_devl_locked() -> mlx5_detach_device() -> del_adev() -> mlx5e_remove() -> mlx5e_destroy_devlink() -> devlink_free() -> unregister_netdevice_notifier() (takes down_write(&pernet_ops_rwsem) Steps to reproduce: $ modprobe mlx5_core $ ip netns add ns1 $ devlink dev reload pci/0000:08:00.0 netns ns1 $ ip netns del ns1 Resolve this by converting the notifier from per-devlink instance to a static one registered during init phase and leaving it registered forever. Use this notifier for all devlink port instances created later on. Note what a tree needs this fix only in case all of the cited fixes commits are present. Reported-by: Moshe Shemesh Fixes: 565b4824c39f ("devlink: change port event netdev notifier from per-net to global") Fixes: ee75f1fc44dd ("net/mlx5e: Create separate devlink instance for ethernet auxiliary device") Fixes: 72ed5d5624af ("net/mlx5: Suspend auxiliary devices only in case of PCI device suspend") Signed-off-by: Jiri Pirko Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230510144621.932017-1-jiri@resnulli.us Signed-off-by: Jakub Kicinski

devlink: convert param list to xarray

2023-02-13T09:49:14Z

Loose the linked list for params and use xarray instead. Note that this is required to be eventually possible to call devl_param_driverinit_value_get() without holding instance lock. Signed-off-by: Jiri Pirko Reviewed-by: Simon Horman Acked-by: Jakub Kicinski Reviewed-by: Jacob Keller Signed-off-by: David S. Miller

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

2023-02-09T20:25:40Z

net/devlink/leftover.c / net/core/devlink.c: 565b4824c39f ("devlink: change port event netdev notifier from per-net to global") f05bd8ebeb69 ("devlink: move code to a dedicated directory") 687125b5799c ("devlink: split out core code") https://lore.kernel.org/all/20230208094657.379f2b1a@canb.auug.org.au/ Signed-off-by: Jakub Kicinski

devlink: remove devlink features

2023-01-30T08:37:46Z

Devlink features were introduced to disallow devlink reload calls of userspace before the devlink was fully initialized. The reason for this workaround was the fact that devlink reload was originally called without devlink instance lock held. However, with recent changes that converted devlink reload to be performed under devlink instance lock, this is redundant so remove devlink features entirely. Note that mlx5 used this to enable devlink reload conditionally only when device didn't act as multi port slave. Move the multi port check into mlx5_devlink_reload_down() callback alongside with the other checks preventing the device from reload in certain states. Signed-off-by: Jiri Pirko Reviewed-by: Jacob Keller Signed-off-by: David S. Miller

devlink: remove reporters_lock

2023-01-20T03:08:37Z

Similar to other devlink objects, rely on devlink instance lock and remove object specific reporters_lock. Signed-off-by: Jiri Pirko Reviewed-by: Jacob Keller Signed-off-by: Jakub Kicinski

devlink: remove linecards lock

2023-01-20T03:08:37Z

Similar to other devlink objects, convert the linecards list to be protected by devlink instance lock. Alongside with that rename the create/destroy() functions to devl_* to indicate the devlink instance lock needs to be held while calling them. Signed-off-by: Jiri Pirko Reviewed-by: Ido Schimmel Reviewed-by: Jacob Keller Signed-off-by: Jakub Kicinski

devlink: keep the instance mutex alive until references are gone

2023-01-12T04:49:32Z

The reference needs to keep the instance memory around, but also the instance lock must remain valid. Users will take the lock, check registration status and release the lock. mutex_destroy() etc. belong in the same place as the freeing of the memory. Unfortunately lockdep_unregister_key() sleeps so we need to switch the an rcu_work. Note that the problem is a bit hard to repro, because devlink_pernet_pre_exit() iterates over registered instances. AFAIU the instances must get devlink_free()d concurrently with the namespace getting deleted for the problem to occur. Reported-by: syzbot+d94d214ea473e218fc89@syzkaller.appspotmail.com Reported-by: syzbot+9f0dd863b87113935acf@syzkaller.appspotmail.com Fixes: 9053637e0da7 ("devlink: remove the registration guarantee of references") Reviewed-by: Jiri Pirko Reviewed-by: Jacob Keller Link: https://lore.kernel.org/r/20230111042908.988199-1-kuba@kernel.org Signed-off-by: Jakub Kicinski

devlink: don't require setting features before registration

2023-01-06T12:56:19Z

Requiring devlink_set_features() to be run before devlink is registered is overzealous. devlink_set_features() itself is a leftover from old workarounds which were trying to prevent initiating reload before probe was complete. Signed-off-by: Jakub Kicinski Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller

devlink: remove the registration guarantee of references

2023-01-06T12:56:19Z

The objective of exposing the devlink instance locks to drivers was to let them use these locks to prevent user space from accessing the device before it's fully initialized. This is difficult because devlink_unregister() waits for all references to be released, meaning that devlink_unregister() can't itself be called under the instance lock. To avoid this issue devlink_register() was moved after subobject registration a while ago. Unfortunately the netdev paths get a hold of the devlink instances _before_ they are registered. Ideally netdev should wait for devlink init to finish (synchronizing on the instance lock). This can't work because we don't know if the instance will _ever_ be registered (in case of failures it may not). The other option of returning an error until devlink_register() is called is unappealing (user space would get a notification netdev exist but would have to wait arbitrary amount of time before accessing some of its attributes). Weaken the guarantees of the devlink references. Holding a reference will now only guarantee that the memory of the object is around. Another way of looking at it is that the reference now protects the object not its "registered" status. Use devlink instance lock to synchronize unregistration. This implies that releasing of the "main" reference of the devlink instance moves from devlink_unregister() to devlink_free(). Reviewed-by: Jacob Keller Signed-off-by: Jakub Kicinski Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller