| Message ID | 1463248198-3926-1-git-send-email-me@bobcopeland.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Johannes Berg |
| Headers | show |
On 2016-05-14 19:49, Bob Copeland wrote: > Currently, the mesh paths associated with a nexthop station are cleaned > up in the following code path: > > __sta_info_destroy_part1 > synchronize_net() > __sta_info_destroy_part2 > -> cleanup_single_sta > -> mesh_sta_cleanup > -> mesh_plink_deactivate > -> mesh_path_flush_by_nexthop > > However, there are a couple of problems here: > > 1) the paths aren't flushed at all if the MPM is running in userspace > (e.g. when using wpa_supplicant or authsae) > > 2) there is no synchronize_rcu between removing the path and readers > accessing the nexthop, which means the following race is possible: > > CPU0 CPU1 > ~~~~ ~~~~ > sta_info_destroy_part1() > synchronize_net() > rcu_read_lock() > mesh_nexthop_resolve() > mpath = mesh_path_lookup() > [...] -> mesh_path_flush_by_nexthop() > sta = rcu_dereference( > mpath->next_hop) > kfree(sta) > access sta <-- CRASH > > Fix both of these by unconditionally flushing paths in part1 of sta > destroy. The synchronize_net() will then happen after paths > are flushed, preventing mesh_path_lookup from finding a path with > the to-be-freed nexthop sta. > > Also, add a new sta bit and a check in mesh_path_assign_nexthop() to > avoid adding it back between the flush and the synchronize_net(). > > Fixes this crash: > > [ 348.529295] BUG: unable to handle kernel paging request at 00020040 > [ 348.530014] IP: [<f929245d>] ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211] > [ 348.530014] *pde = 00000000 > [ 348.530014] Oops: 0000 [#1] PREEMPT > [ 348.530014] Modules linked in: drbg ansi_cprng ctr ccm ppp_generic slhc ipt_MASQUERADE nf_nat_masquerade_ipv4 8021q ] > [ 348.530014] CPU: 0 PID: 20597 Comm: wget Tainted: G O 4.6.0-rc5-wt=V1 #1 > [ 348.530014] Hardware name: To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080016 11/07/2014 > [ 348.530014] task: f64fa280 ti: f4f9c000 task.ti: f4f9c000 > [ 348.530014] EIP: 0060:[<f929245d>] EFLAGS: 00010246 CPU: 0 > [ 348.530014] EIP is at ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211] > [ 348.530014] EAX: f4ce63e0 EBX: 00000088 ECX: f3788416 EDX: 00020008 > [ 348.530014] ESI: 00000000 EDI: 00000088 EBP: f6409a4c ESP: f6409a40 > [ 348.530014] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 > [ 348.530014] CR0: 80050033 CR2: 00020040 CR3: 33190000 CR4: 00000690 > [ 348.530014] Stack: > [ 348.530014] 00000000 f4ce63e0 f5f9bd80 f6409a64 f9291d80 0000ce67 f5d51e00 f4ce63e0 > [ 348.530014] f3788416 f6409a80 f9291dc1 f4ce8320 f4ce63e0 f5d51e00 f4ce63e0 f4ce8320 > [ 348.530014] f6409a98 f9277f6f 00000000 00000000 0000007c 00000000 f6409b2c f9278dd1 > [ 348.530014] Call Trace: > [ 348.530014] [<f9291d80>] mesh_nexthop_lookup+0xbb/0xc8 [mac80211] > [ 348.530014] [<f9291dc1>] mesh_nexthop_resolve+0x34/0xd8 [mac80211] > [ 348.530014] [<f9277f6f>] ieee80211_xmit+0x92/0xc1 [mac80211] > [ 348.530014] [<f9278dd1>] __ieee80211_subif_start_xmit+0x807/0x83c [mac80211] > [ 348.530014] [<c04df012>] ? sch_direct_xmit+0xd7/0x1b3 > [ 348.530014] [<c022a8c6>] ? __local_bh_enable_ip+0x5d/0x7b > [ 348.530014] [<f956870c>] ? nf_nat_ipv4_out+0x4c/0xd0 [nf_nat_ipv4] > [ 348.530014] [<f957e036>] ? iptable_nat_ipv4_fn+0xf/0xf [iptable_nat] > [ 348.530014] [<c04c6f45>] ? netif_skb_features+0x14d/0x30a > [ 348.530014] [<f9278e10>] ieee80211_subif_start_xmit+0xa/0xe [mac80211] > [ 348.530014] [<c04c769c>] dev_hard_start_xmit+0x1f8/0x267 > [ 348.530014] [<c04c7261>] ? validate_xmit_skb.isra.120.part.121+0x10/0x253 > [ 348.530014] [<c04defc6>] sch_direct_xmit+0x8b/0x1b3 > [ 348.530014] [<c04c7a9c>] __dev_queue_xmit+0x2c8/0x513 > [ 348.530014] [<c04c7cfb>] dev_queue_xmit+0xa/0xc > [ 348.530014] [<f91bfc7a>] batadv_send_skb_packet+0xd6/0xec [batman_adv] > [ 348.530014] [<f91bfdc4>] batadv_send_unicast_skb+0x15/0x4a [batman_adv] > [ 348.530014] [<f91b5938>] batadv_dat_send_data+0x27e/0x310 [batman_adv] > [ 348.530014] [<f91c30b5>] ? batadv_tt_global_hash_find.isra.11+0x8/0xa [batman_adv] > [ 348.530014] [<f91b63f3>] batadv_dat_snoop_outgoing_arp_request+0x208/0x23d [batman_adv] > [ 348.530014] [<f91c0cd9>] batadv_interface_tx+0x206/0x385 [batman_adv] > [ 348.530014] [<c04c769c>] dev_hard_start_xmit+0x1f8/0x267 > [ 348.530014] [<c04c7261>] ? validate_xmit_skb.isra.120.part.121+0x10/0x253 > [ 348.530014] [<c04defc6>] sch_direct_xmit+0x8b/0x1b3 > [ 348.530014] [<c04c7a9c>] __dev_queue_xmit+0x2c8/0x513 > [ 348.530014] [<f80cbd2a>] ? igb_xmit_frame+0x57/0x72 [igb] > [ 348.530014] [<c04c7cfb>] dev_queue_xmit+0xa/0xc > [ 348.530014] [<f843a326>] br_dev_queue_push_xmit+0xeb/0xfb [bridge] > [ 348.530014] [<f843a35f>] br_forward_finish+0x29/0x74 [bridge] > [ 348.530014] [<f843a23b>] ? deliver_clone+0x3b/0x3b [bridge] > [ 348.530014] [<f843a714>] __br_forward+0x89/0xe7 [bridge] > [ 348.530014] [<f843a336>] ? br_dev_queue_push_xmit+0xfb/0xfb [bridge] > [ 348.530014] [<f843a234>] deliver_clone+0x34/0x3b [bridge] > [ 348.530014] [<f843a68b>] ? br_flood+0x95/0x95 [bridge] > [ 348.530014] [<f843a66d>] br_flood+0x77/0x95 [bridge] > [ 348.530014] [<f843a809>] br_flood_forward+0x13/0x1a [bridge] > [ 348.530014] [<f843a68b>] ? br_flood+0x95/0x95 [bridge] > [ 348.530014] [<f843b877>] br_handle_frame_finish+0x392/0x3db [bridge] > [ 348.530014] [<c04e9b2b>] ? nf_iterate+0x2b/0x6b > [ 348.530014] [<f843baa6>] br_handle_frame+0x1e6/0x240 [bridge] > [ 348.530014] [<f843b4e5>] ? br_handle_local_finish+0x6a/0x6a [bridge] > [ 348.530014] [<c04c4ba0>] __netif_receive_skb_core+0x43a/0x66b > [ 348.530014] [<f843b8c0>] ? br_handle_frame_finish+0x3db/0x3db [bridge] > [ 348.530014] [<c023cea4>] ? resched_curr+0x19/0x37 > [ 348.530014] [<c0240707>] ? check_preempt_wakeup+0xbf/0xfe > [ 348.530014] [<c0255dec>] ? ktime_get_with_offset+0x5c/0xfc > [ 348.530014] [<c04c4fc1>] __netif_receive_skb+0x47/0x55 > [ 348.530014] [<c04c57ba>] netif_receive_skb_internal+0x40/0x5a > [ 348.530014] [<c04c61ef>] napi_gro_receive+0x3a/0x94 > [ 348.530014] [<f80ce8d5>] igb_poll+0x6fd/0x9ad [igb] > [ 348.530014] [<c0242bd8>] ? swake_up_locked+0x14/0x26 > [ 348.530014] [<c04c5d29>] net_rx_action+0xde/0x250 > [ 348.530014] [<c022a743>] __do_softirq+0x8a/0x163 > [ 348.530014] [<c022a6b9>] ? __hrtimer_tasklet_trampoline+0x19/0x19 > [ 348.530014] [<c021100f>] do_softirq_own_stack+0x26/0x2c > [ 348.530014] <IRQ> > [ 348.530014] [<c022a957>] irq_exit+0x31/0x6f > [ 348.530014] [<c0210eb2>] do_IRQ+0x8d/0xa0 > [ 348.530014] [<c058152c>] common_interrupt+0x2c/0x40 > [ 348.530014] Code: e7 8c 00 66 81 ff 88 00 75 12 85 d2 75 0e b2 c3 b8 83 e9 29 f9 e8 a7 5f f9 c6 eb 74 66 81 e3 8c 005 > [ 348.530014] EIP: [<f929245d>] ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211] SS:ESP 0068:f6409a40 > [ 348.530014] CR2: 0000000000020040 > [ 348.530014] ---[ end trace 48556ac26779732e ]--- > [ 348.530014] Kernel panic - not syncing: Fatal exception in interrupt > [ 348.530014] Kernel Offset: disabled > > Cc: stable@vger.kernel.org > Reported-by: Fred Veldini <fred.veldini@gmail.com> > Tested-by: Fred Veldini <fred.veldini@gmail.com> > Signed-off-by: Bob Copeland <me@bobcopeland.com> > --- > From git history, this appears to go back to earliest commits adding > authsae support. I reproduced in a 4.4 kernel, which predates all of > the mesh pathtable rework, though it is harder to hit there than in > the current code. > > This is slightly different from the version Fred tested (CCed) -- > the version I sent him didn't have the BLOCK_MPATH part, but that > seems necessary to me to prevent re-adding in hwmp_route_info_get(). > But I can reproduce the above crash and this patch fixes it for > me. > --- > net/mac80211/mesh_pathtbl.c | 4 ++++ > net/mac80211/sta_info.c | 10 ++++++++++ > net/mac80211/sta_info.h | 2 ++ > 3 files changed, 16 insertions(+) > > diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h > index c8b8ccc370eb..65ecd3746c3b 100644 > --- a/net/mac80211/sta_info.h > +++ b/net/mac80211/sta_info.h > @@ -70,6 +70,7 @@ > * @WLAN_STA_MPSP_RECIPIENT: local STA is recipient of a MPSP. > * @WLAN_STA_PS_DELIVER: station woke up, but we're still blocking TX > * until pending frames are delivered > + * @WLAN_STA_BLOCK_MPATH: block adding this station as a mesh path > * > * @NUM_WLAN_STA_FLAGS: number of defined flags > */ > @@ -100,6 +101,7 @@ enum ieee80211_sta_info_flags { > WLAN_STA_MPSP_OWNER, > WLAN_STA_MPSP_RECIPIENT, > WLAN_STA_PS_DELIVER, > + WLAN_STA_BLOCK_MPATH, I think this flag needs to be added to sta_flag_names in debugfs_sta.c - Felix -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, May 14, 2016 at 08:54:13PM +0200, Felix Fietkau wrote: > > + WLAN_STA_BLOCK_MPATH, > I think this flag needs to be added to sta_flag_names in debugfs_sta.c > > - Felix Good point. I also missed the part where mesh_path_assign_nexthop should return an error to indicate the path shouldn't be activated. So, I'll send a v2 tomorrow, additional comments welcome in the meantime.
On Sat, May 14, 2016 at 08:54:13PM +0200, Felix Fietkau wrote: > > + WLAN_STA_BLOCK_MPATH, > I think this flag needs to be added to sta_flag_names in debugfs_sta.c On further reflection, using a flag for this is racy anyway, even if quite narrow. Maybe I should just flush in part2 unconditionally and have a second synchronize_net().
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c index 6db2ddfa0695..798c522b6522 100644 --- a/net/mac80211/mesh_pathtbl.c +++ b/net/mac80211/mesh_pathtbl.c @@ -87,6 +87,10 @@ void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta) struct ieee80211_hdr *hdr; unsigned long flags; + /* sta is being deleted, don't add back */ + if (test_sta_flag(sta, WLAN_STA_BLOCK_MPATH)) + return; + rcu_assign_pointer(mpath->next_hop, sta); spin_lock_irqsave(&mpath->frame_queue.lock, flags); diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 5ccfdbd406bd..f2a1bfa53c04 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -914,6 +914,16 @@ static int __must_check __sta_info_destroy_part1(struct sta_info *sta) list_del_rcu(&sta->list); sta->removed = true; + /* + * Remove all path table references to the station (and prevent + * adding new ones) so that new mesh transmissions won't use it + * as a next hop. + */ + if (ieee80211_vif_is_mesh(&sdata->vif)) { + set_sta_flag(sta, WLAN_STA_BLOCK_MPATH); + mesh_path_flush_by_nexthop(sta); + } + drv_sta_pre_rcu_remove(local, sta->sdata, sta); if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN && diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index c8b8ccc370eb..65ecd3746c3b 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -70,6 +70,7 @@ * @WLAN_STA_MPSP_RECIPIENT: local STA is recipient of a MPSP. * @WLAN_STA_PS_DELIVER: station woke up, but we're still blocking TX * until pending frames are delivered + * @WLAN_STA_BLOCK_MPATH: block adding this station as a mesh path * * @NUM_WLAN_STA_FLAGS: number of defined flags */ @@ -100,6 +101,7 @@ enum ieee80211_sta_info_flags { WLAN_STA_MPSP_OWNER, WLAN_STA_MPSP_RECIPIENT, WLAN_STA_PS_DELIVER, + WLAN_STA_BLOCK_MPATH, NUM_WLAN_STA_FLAGS, };
Currently, the mesh paths associated with a nexthop station are cleaned up in the following code path: __sta_info_destroy_part1 synchronize_net() __sta_info_destroy_part2 -> cleanup_single_sta -> mesh_sta_cleanup -> mesh_plink_deactivate -> mesh_path_flush_by_nexthop However, there are a couple of problems here: 1) the paths aren't flushed at all if the MPM is running in userspace (e.g. when using wpa_supplicant or authsae) 2) there is no synchronize_rcu between removing the path and readers accessing the nexthop, which means the following race is possible: CPU0 CPU1 ~~~~ ~~~~ sta_info_destroy_part1() synchronize_net() rcu_read_lock() mesh_nexthop_resolve() mpath = mesh_path_lookup() [...] -> mesh_path_flush_by_nexthop() sta = rcu_dereference( mpath->next_hop) kfree(sta) access sta <-- CRASH Fix both of these by unconditionally flushing paths in part1 of sta destroy. The synchronize_net() will then happen after paths are flushed, preventing mesh_path_lookup from finding a path with the to-be-freed nexthop sta. Also, add a new sta bit and a check in mesh_path_assign_nexthop() to avoid adding it back between the flush and the synchronize_net(). Fixes this crash: [ 348.529295] BUG: unable to handle kernel paging request at 00020040 [ 348.530014] IP: [<f929245d>] ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211] [ 348.530014] *pde = 00000000 [ 348.530014] Oops: 0000 [#1] PREEMPT [ 348.530014] Modules linked in: drbg ansi_cprng ctr ccm ppp_generic slhc ipt_MASQUERADE nf_nat_masquerade_ipv4 8021q ] [ 348.530014] CPU: 0 PID: 20597 Comm: wget Tainted: G O 4.6.0-rc5-wt=V1 #1 [ 348.530014] Hardware name: To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080016 11/07/2014 [ 348.530014] task: f64fa280 ti: f4f9c000 task.ti: f4f9c000 [ 348.530014] EIP: 0060:[<f929245d>] EFLAGS: 00010246 CPU: 0 [ 348.530014] EIP is at ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211] [ 348.530014] EAX: f4ce63e0 EBX: 00000088 ECX: f3788416 EDX: 00020008 [ 348.530014] ESI: 00000000 EDI: 00000088 EBP: f6409a4c ESP: f6409a40 [ 348.530014] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 [ 348.530014] CR0: 80050033 CR2: 00020040 CR3: 33190000 CR4: 00000690 [ 348.530014] Stack: [ 348.530014] 00000000 f4ce63e0 f5f9bd80 f6409a64 f9291d80 0000ce67 f5d51e00 f4ce63e0 [ 348.530014] f3788416 f6409a80 f9291dc1 f4ce8320 f4ce63e0 f5d51e00 f4ce63e0 f4ce8320 [ 348.530014] f6409a98 f9277f6f 00000000 00000000 0000007c 00000000 f6409b2c f9278dd1 [ 348.530014] Call Trace: [ 348.530014] [<f9291d80>] mesh_nexthop_lookup+0xbb/0xc8 [mac80211] [ 348.530014] [<f9291dc1>] mesh_nexthop_resolve+0x34/0xd8 [mac80211] [ 348.530014] [<f9277f6f>] ieee80211_xmit+0x92/0xc1 [mac80211] [ 348.530014] [<f9278dd1>] __ieee80211_subif_start_xmit+0x807/0x83c [mac80211] [ 348.530014] [<c04df012>] ? sch_direct_xmit+0xd7/0x1b3 [ 348.530014] [<c022a8c6>] ? __local_bh_enable_ip+0x5d/0x7b [ 348.530014] [<f956870c>] ? nf_nat_ipv4_out+0x4c/0xd0 [nf_nat_ipv4] [ 348.530014] [<f957e036>] ? iptable_nat_ipv4_fn+0xf/0xf [iptable_nat] [ 348.530014] [<c04c6f45>] ? netif_skb_features+0x14d/0x30a [ 348.530014] [<f9278e10>] ieee80211_subif_start_xmit+0xa/0xe [mac80211] [ 348.530014] [<c04c769c>] dev_hard_start_xmit+0x1f8/0x267 [ 348.530014] [<c04c7261>] ? validate_xmit_skb.isra.120.part.121+0x10/0x253 [ 348.530014] [<c04defc6>] sch_direct_xmit+0x8b/0x1b3 [ 348.530014] [<c04c7a9c>] __dev_queue_xmit+0x2c8/0x513 [ 348.530014] [<c04c7cfb>] dev_queue_xmit+0xa/0xc [ 348.530014] [<f91bfc7a>] batadv_send_skb_packet+0xd6/0xec [batman_adv] [ 348.530014] [<f91bfdc4>] batadv_send_unicast_skb+0x15/0x4a [batman_adv] [ 348.530014] [<f91b5938>] batadv_dat_send_data+0x27e/0x310 [batman_adv] [ 348.530014] [<f91c30b5>] ? batadv_tt_global_hash_find.isra.11+0x8/0xa [batman_adv] [ 348.530014] [<f91b63f3>] batadv_dat_snoop_outgoing_arp_request+0x208/0x23d [batman_adv] [ 348.530014] [<f91c0cd9>] batadv_interface_tx+0x206/0x385 [batman_adv] [ 348.530014] [<c04c769c>] dev_hard_start_xmit+0x1f8/0x267 [ 348.530014] [<c04c7261>] ? validate_xmit_skb.isra.120.part.121+0x10/0x253 [ 348.530014] [<c04defc6>] sch_direct_xmit+0x8b/0x1b3 [ 348.530014] [<c04c7a9c>] __dev_queue_xmit+0x2c8/0x513 [ 348.530014] [<f80cbd2a>] ? igb_xmit_frame+0x57/0x72 [igb] [ 348.530014] [<c04c7cfb>] dev_queue_xmit+0xa/0xc [ 348.530014] [<f843a326>] br_dev_queue_push_xmit+0xeb/0xfb [bridge] [ 348.530014] [<f843a35f>] br_forward_finish+0x29/0x74 [bridge] [ 348.530014] [<f843a23b>] ? deliver_clone+0x3b/0x3b [bridge] [ 348.530014] [<f843a714>] __br_forward+0x89/0xe7 [bridge] [ 348.530014] [<f843a336>] ? br_dev_queue_push_xmit+0xfb/0xfb [bridge] [ 348.530014] [<f843a234>] deliver_clone+0x34/0x3b [bridge] [ 348.530014] [<f843a68b>] ? br_flood+0x95/0x95 [bridge] [ 348.530014] [<f843a66d>] br_flood+0x77/0x95 [bridge] [ 348.530014] [<f843a809>] br_flood_forward+0x13/0x1a [bridge] [ 348.530014] [<f843a68b>] ? br_flood+0x95/0x95 [bridge] [ 348.530014] [<f843b877>] br_handle_frame_finish+0x392/0x3db [bridge] [ 348.530014] [<c04e9b2b>] ? nf_iterate+0x2b/0x6b [ 348.530014] [<f843baa6>] br_handle_frame+0x1e6/0x240 [bridge] [ 348.530014] [<f843b4e5>] ? br_handle_local_finish+0x6a/0x6a [bridge] [ 348.530014] [<c04c4ba0>] __netif_receive_skb_core+0x43a/0x66b [ 348.530014] [<f843b8c0>] ? br_handle_frame_finish+0x3db/0x3db [bridge] [ 348.530014] [<c023cea4>] ? resched_curr+0x19/0x37 [ 348.530014] [<c0240707>] ? check_preempt_wakeup+0xbf/0xfe [ 348.530014] [<c0255dec>] ? ktime_get_with_offset+0x5c/0xfc [ 348.530014] [<c04c4fc1>] __netif_receive_skb+0x47/0x55 [ 348.530014] [<c04c57ba>] netif_receive_skb_internal+0x40/0x5a [ 348.530014] [<c04c61ef>] napi_gro_receive+0x3a/0x94 [ 348.530014] [<f80ce8d5>] igb_poll+0x6fd/0x9ad [igb] [ 348.530014] [<c0242bd8>] ? swake_up_locked+0x14/0x26 [ 348.530014] [<c04c5d29>] net_rx_action+0xde/0x250 [ 348.530014] [<c022a743>] __do_softirq+0x8a/0x163 [ 348.530014] [<c022a6b9>] ? __hrtimer_tasklet_trampoline+0x19/0x19 [ 348.530014] [<c021100f>] do_softirq_own_stack+0x26/0x2c [ 348.530014] <IRQ> [ 348.530014] [<c022a957>] irq_exit+0x31/0x6f [ 348.530014] [<c0210eb2>] do_IRQ+0x8d/0xa0 [ 348.530014] [<c058152c>] common_interrupt+0x2c/0x40 [ 348.530014] Code: e7 8c 00 66 81 ff 88 00 75 12 85 d2 75 0e b2 c3 b8 83 e9 29 f9 e8 a7 5f f9 c6 eb 74 66 81 e3 8c 005 [ 348.530014] EIP: [<f929245d>] ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211] SS:ESP 0068:f6409a40 [ 348.530014] CR2: 0000000000020040 [ 348.530014] ---[ end trace 48556ac26779732e ]--- [ 348.530014] Kernel panic - not syncing: Fatal exception in interrupt [ 348.530014] Kernel Offset: disabled Cc: stable@vger.kernel.org Reported-by: Fred Veldini <fred.veldini@gmail.com> Tested-by: Fred Veldini <fred.veldini@gmail.com> Signed-off-by: Bob Copeland <me@bobcopeland.com> --- From git history, this appears to go back to earliest commits adding authsae support. I reproduced in a 4.4 kernel, which predates all of the mesh pathtable rework, though it is harder to hit there than in the current code. This is slightly different from the version Fred tested (CCed) -- the version I sent him didn't have the BLOCK_MPATH part, but that seems necessary to me to prevent re-adding in hwmp_route_info_get(). But I can reproduce the above crash and this patch fixes it for me. --- net/mac80211/mesh_pathtbl.c | 4 ++++ net/mac80211/sta_info.c | 10 ++++++++++ net/mac80211/sta_info.h | 2 ++ 3 files changed, 16 insertions(+)