kernel/net/batman-adv/bat_v_elp.c, branch linux-rolling-stable

batman-adv: Avoid double-rtnl_lock ELP metric worker

2026-03-19T15:15:19Z

commit cfc83a3c71517b59c1047db57da31e26a9dc2f33 upstream. batadv_v_elp_get_throughput() might be called when the RTNL lock is already held. This could be problematic when the work queue item is cancelled via cancel_delayed_work_sync() in batadv_v_elp_iface_disable(). In this case, an rtnl_lock() would cause a deadlock. To avoid this, rtnl_trylock() was used in this function to skip the retrieval of the ethtool information in case the RTNL lock was already held. But for cfg80211 interfaces, batadv_get_real_netdev() was called - which also uses rtnl_lock(). The approach for __ethtool_get_link_ksettings() must also be used instead and the lockless version __batadv_get_real_netdev() has to be called. Cc: stable@vger.kernel.org Fixes: 8c8ecc98f5c6 ("batman-adv: Drop unmanaged ELP metric worker") Reported-by: Christian Schmidbauer Signed-off-by: Sven Eckelmann Tested-by: Sören Skaarup Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman

batman-adv: store hard_iface as iflink private data

2025-05-31T08:41:11Z

By passing the hard_iface to netdev_master_upper_dev_link() as private data, we can iterate over hardifs of a mesh interface more efficiently using netdev_for_each_lower_private*() (instead of iterating over the global hardif list). In addition, this will enable resolving a hardif from its netdev using netdev_lower_dev_get_private() and getting rid of the global list altogether in the following patches. A similar approach can be seen in the bonding driver. Signed-off-by: Matthias Schiffer Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Use consistent name for mesh interface

2025-02-22T10:36:22Z

The way how the virtual interface is called inside the batman-adv source code is not consistent. The genl headers call it meshif and the rest of the code calls is (mostly) softif. The genl definitions cannot be touched because they are part of the UAPI. But the rest of the batman-adv code can be touched to have a consistent name again. The bulk of the renaming was done using sed -i -e 's/soft\(-\|\_\| \|\)i\([nf]\)/mesh\1i\2/g' \ -e 's/SOFT\(-\|\_\| \|\)I\([NF]\)/MESH\1I\2/g' and then it was adjusted slightly when proofreading the changes. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Drop unmanaged ELP metric worker

2025-01-22T20:46:42Z

The ELP worker needs to calculate new metric values for all neighbors "reachable" over an interface. Some of the used metric sources require locks which might need to sleep. This sleep is incompatible with the RCU list iterator used for the recorded neighbors. The initial approach to work around of this problem was to queue another work item per neighbor and then run this in a new context. Even when this solved the RCU vs might_sleep() conflict, it has a major problems: Nothing was stopping the work item in case it is not needed anymore - for example because one of the related interfaces was removed or the batman-adv module was unloaded - resulting in potential invalid memory accesses. Directly canceling the metric worker also has various problems: * cancel_work_sync for a to-be-deactivated interface is called with rtnl_lock held. But the code in the ELP metric worker also tries to use rtnl_lock() - which will never return in this case. This also means that cancel_work_sync would never return because it is waiting for the worker to finish. * iterating over the neighbor list for the to-be-deactivated interface is currently done using the RCU specific methods. Which means that it is possible to miss items when iterating over it without the associated spinlock - a behaviour which is acceptable for a periodic metric check but not for a cleanup routine (which must "stop" all still running workers) The better approch is to get rid of the per interface neighbor metric worker and handle everything in the interface worker. The original problems are solved by: * creating a list of neighbors which require new metric information inside the RCU protected context, gathering the metric according to the new list outside the RCU protected context * only use rcu_trylock inside metric gathering code to avoid a deadlock when the cancel_delayed_work_sync is called in the interface removal code (which is called with the rtnl_lock held) Cc: stable@vger.kernel.org Fixes: c833484e5f38 ("batman-adv: ELP - compute the metric based on the estimated throughput") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Ignore neighbor throughput metrics in error case

2025-01-22T20:38:19Z

If a temporary error happened in the evaluation of the neighbor throughput information, then the invalid throughput result should not be stored in the throughtput EWMA. Cc: stable@vger.kernel.org Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: fix panic during interface removal

2025-01-19T21:10:20Z

Reference counting is used to ensure that batadv_hardif_neigh_node and batadv_hard_iface are not freed before/during batadv_v_elp_throughput_metric_update work is finished. But there isn't a guarantee that the hard if will remain associated with a soft interface up until the work is finished. This fixes a crash triggered by reboot that looks like this: Call trace: batadv_v_mesh_free+0xd0/0x4dc [batman_adv] batadv_v_elp_throughput_metric_update+0x1c/0xa4 process_one_work+0x178/0x398 worker_thread+0x2e8/0x4d0 kthread+0xd8/0xdc ret_from_fork+0x10/0x20 (the batadv_v_mesh_free call is misleading, and does not actually happen) I was able to make the issue happen more reliably by changing hardif_neigh->bat_v.metric_work work to be delayed work. This allowed me to track down and confirm the fix. Cc: stable@vger.kernel.org Fixes: c833484e5f38 ("batman-adv: ELP - compute the metric based on the estimated throughput") Signed-off-by: Andy Strohman [sven@narfation.org: prevent entering batadv_v_elp_get_throughput without soft_iface] Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Do not get eth header before batadv_check_management_packet

2023-07-28T13:39:38Z

If received skb in batadv_v_elp_packet_recv or batadv_v_ogm_packet_recv is either cloned or non linearized then its data buffer will be reallocated by batadv_check_management_packet when skb_cow or skb_linearize get called. Thus geting ethernet header address inside skb data buffer before batadv_check_management_packet had any chance to reallocate it could lead to the following kernel panic: Unable to handle kernel paging request at virtual address ffffff8020ab069a Mem abort info: ESR = 0x96000007 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x07: level 3 translation fault Data abort info: ISV = 0, ISS = 0x00000007 CM = 0, WnR = 0 swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000040f45000 [ffffff8020ab069a] pgd=180000007fffa003, p4d=180000007fffa003, pud=180000007fffa003, pmd=180000007fefe003, pte=0068000020ab0706 Internal error: Oops: 96000007 [#1] SMP Modules linked in: ahci_mvebu libahci_platform libahci dvb_usb_af9035 dvb_usb_dib0700 dib0070 dib7000m dibx000_common ath11k_pci ath10k_pci ath10k_core mwl8k_new nf_nat_sip nf_conntrack_sip xhci_plat_hcd xhci_hcd nf_nat_pptp nf_conntrack_pptp at24 sbsa_gwdt CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.15.42-00066-g3242268d425c-dirty #550 Hardware name: A8k (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : batadv_is_my_mac+0x60/0xc0 lr : batadv_v_ogm_packet_recv+0x98/0x5d0 sp : ffffff8000183820 x29: ffffff8000183820 x28: 0000000000000001 x27: ffffff8014f9af00 x26: 0000000000000000 x25: 0000000000000543 x24: 0000000000000003 x23: ffffff8020ab0580 x22: 0000000000000110 x21: ffffff80168ae880 x20: 0000000000000000 x19: ffffff800b561000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 00dc098924ae0032 x14: 0f0405433e0054b0 x13: ffffffff00000080 x12: 0000004000000001 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000000000000 x7 : ffffffc076dae000 x6 : ffffff8000183700 x5 : ffffffc00955e698 x4 : ffffff80168ae000 x3 : ffffff80059cf000 x2 : ffffff800b561000 x1 : ffffff8020ab0696 x0 : ffffff80168ae880 Call trace: batadv_is_my_mac+0x60/0xc0 batadv_v_ogm_packet_recv+0x98/0x5d0 batadv_batman_skb_recv+0x1b8/0x244 __netif_receive_skb_core.isra.0+0x440/0xc74 __netif_receive_skb_one_core+0x14/0x20 netif_receive_skb+0x68/0x140 br_pass_frame_up+0x70/0x80 br_handle_frame_finish+0x108/0x284 br_handle_frame+0x190/0x250 __netif_receive_skb_core.isra.0+0x240/0xc74 __netif_receive_skb_list_core+0x6c/0x90 netif_receive_skb_list_internal+0x1f4/0x310 napi_complete_done+0x64/0x1d0 gro_cell_poll+0x7c/0xa0 __napi_poll+0x34/0x174 net_rx_action+0xf8/0x2a0 _stext+0x12c/0x2ac run_ksoftirqd+0x4c/0x7c smpboot_thread_fn+0x120/0x210 kthread+0x140/0x150 ret_from_fork+0x10/0x20 Code: f9403844 eb03009f 54fffee1 f94 Thus ethernet header address should only be fetched after batadv_check_management_packet has been called. Fixes: 0da0035942d4 ("batman-adv: OGMv2 - add basic infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Remi Pommarel Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

batman-adv: Drop prandom.h includes

2023-01-06T07:43:02Z

The commit 8032bf1233a7 ("treewide: use get_random_u32_below() instead of deprecated function") replaced the prandom.h function prandom_u32_max with the random.h function get_random_u32_below. There is no need to still include prandom.h. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich

treewide: use get_random_u32_below() instead of deprecated function

2022-11-18T01:15:15Z

This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Acked-by: Darrick J. Wong # for xfs Reviewed-by: SeongJae Park # for damon Reviewed-by: Jason Gunthorpe # for infiniband Reviewed-by: Russell King (Oracle) # for arm Acked-by: Ulf Hansson # for mmc Signed-off-by: Jason A. Donenfeld

batman-adv: Drop initialization of flexible ethtool_link_ksettings

2022-08-20T07:40:51Z

The commit 94dfc73e7cf4 ("treewide: uapi: Replace zero-length arrays with flexible-array members") changed various structures from using 0-length arrays to flexible arrays net/batman-adv/bat_v_elp.c: note: in included file: ./include/linux/ethtool.h:148:38: warning: nested flexible array net/batman-adv/bat_v_elp.c:128:9: warning: using sizeof on a flexible structure In theory, this could be worked around by using {} as initializer for the variable on the stack. But this variable doesn't has to be initialized at all by the caller of __ethtool_get_link_ksettings - everything will be initialized by the callee when no error occurs. Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich