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authorLuka Perkov <luka.perkov@sartura.hr>2016-06-23 13:57:21 +0200
committerGitHub <noreply@github.com>2016-06-23 13:57:21 +0200
commit282b917e47d9ae5017e1e426face9b75cb7aabd0 (patch)
tree3284ca2d20d9c8d7a4563c6446675c1ecf3feac2 /package/kernel/mac80211/patches/303-mac80211-mesh-flush-mesh-paths-unconditionally.patch
parent34d432b05312de6d9575c559db8209809489096d (diff)
parent441a9c879ba6562ea9f431cf33bbb0c0400d5fd0 (diff)
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Merge pull request #11 from wigyori/master
pull req for 4.4.12, ar71xx/mediatek updates, package upgrades
Diffstat (limited to 'package/kernel/mac80211/patches/303-mac80211-mesh-flush-mesh-paths-unconditionally.patch')
-rw-r--r--package/kernel/mac80211/patches/303-mac80211-mesh-flush-mesh-paths-unconditionally.patch146
1 files changed, 146 insertions, 0 deletions
diff --git a/package/kernel/mac80211/patches/303-mac80211-mesh-flush-mesh-paths-unconditionally.patch b/package/kernel/mac80211/patches/303-mac80211-mesh-flush-mesh-paths-unconditionally.patch
new file mode 100644
index 0000000000..518d0a31da
--- /dev/null
+++ b/package/kernel/mac80211/patches/303-mac80211-mesh-flush-mesh-paths-unconditionally.patch
@@ -0,0 +1,146 @@
+From: Bob Copeland <me@bobcopeland.com>
+Date: Sun, 15 May 2016 13:19:16 -0400
+Subject: [PATCH] mac80211: mesh: flush mesh paths unconditionally
+
+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 before destroying
+the sta, and by adding a synchronize_net() after path flush to ensure
+no active readers can still dereference the sta.
+
+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>
+---
+
+--- a/net/mac80211/mesh.c
++++ b/net/mac80211/mesh.c
+@@ -161,6 +161,10 @@ void mesh_sta_cleanup(struct sta_info *s
+ del_timer_sync(&sta->mesh->plink_timer);
+ }
+
++ /* make sure no readers can access nexthop sta from here on */
++ mesh_path_flush_by_nexthop(sta);
++ synchronize_net();
++
+ if (changed)
+ ieee80211_mbss_info_change_notify(sdata, changed);
+ }