linux/net/mac80211
Bob Copeland fe7a7c5762 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>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2016-05-31 12:12:53 +02:00
..
aes_ccm.c mac80211: Switch to new AEAD interface 2015-05-28 11:23:20 +08:00
aes_ccm.h mac80111: Add CCMP-256 cipher 2015-01-27 11:07:35 +01:00
aes_cmac.c mac80211: remove ieee80211_aes_cmac_calculate_k1_k2() 2015-08-13 11:31:45 +02:00
aes_cmac.h mac80111: Add BIP-CMAC-256 cipher 2015-01-27 11:09:13 +01:00
aes_gcm.c mac80211: Switch to new AEAD interface 2015-05-28 11:23:20 +08:00
aes_gcm.h mac80111: Add GCMP and GCMP-256 ciphers 2015-01-27 11:06:09 +01:00
aes_gmac.c mac80211: Switch to new AEAD interface 2015-05-28 11:23:20 +08:00
aes_gmac.h mac80111: Add BIP-GMAC-128 and BIP-GMAC-256 ciphers 2015-01-27 11:10:13 +01:00
agg-rx.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-03-08 12:34:12 -05:00
agg-tx.c mac80211: add A-MSDU tx support 2016-04-06 13:18:19 +02:00
cfg.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
chan.c mac80211: recalc min_def chanctx even when chandef is identical 2016-04-05 10:51:08 +02:00
debug.h mac80211: 802.11p OCB mode support 2014-11-04 13:18:21 +01:00
debugfs_key.c mac80211: move TKIP TX IVs to public part of key struct 2016-02-24 09:04:38 +01:00
debugfs_key.h
debugfs_netdev.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
debugfs_netdev.h mac80211: fix some missing includes 2014-04-09 14:49:43 +02:00
debugfs_sta.c mac80211: clean up station flags debugfs 2016-04-05 12:12:26 +02:00
debugfs_sta.h
debugfs.c mac80211: add A-MSDU tx support 2016-04-06 13:18:19 +02:00
debugfs.h mac80211: fix some missing includes 2014-04-09 14:49:43 +02:00
driver-ops.c mac80211: pass block ack session timeout to to driver 2016-01-14 11:13:17 +01:00
driver-ops.h mac80211: synchronize driver rx queues before removing a station 2016-04-05 10:56:34 +02:00
ethtool.c mac80211: move station statistics into sub-structs 2015-10-21 10:08:22 +02:00
ht.c mac80211: limit the A-MSDU Tx based on peer's capabilities 2016-02-24 09:04:20 +01:00
ibss.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
ieee80211_i.h cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
iface.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-05-04 00:52:29 -04:00
Kconfig mac80211: use DECLARE_EWMA 2015-08-14 17:49:53 +02:00
key.c mac80211: add fast-rx path 2016-04-06 13:18:18 +02:00
key.h mac80211: move TKIP TX IVs to public part of key struct 2016-02-24 09:04:38 +01:00
led.c mac80211: fix throughput LED trigger 2015-05-11 19:16:04 +02:00
led.h mac80211: make LED triggering depend on activation 2015-05-05 14:21:56 +02:00
main.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
Makefile mac80211: remove event.c 2015-10-14 18:40:26 +02:00
mesh_hwmp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-04-09 17:41:41 -04:00
mesh_pathtbl.c mac80211: mesh: embed gates hlist head directly 2016-04-05 21:34:51 +02:00
mesh_plink.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
mesh_ps.c mac80211: mesh: separate plid and aid concepts 2015-07-17 15:47:11 +02:00
mesh_sync.c mac80211: move mesh related station fields to own struct 2015-07-17 15:38:06 +02:00
mesh.c mac80211: mesh: flush mesh paths unconditionally 2016-05-31 12:12:53 +02:00
mesh.h mac80211: mesh: fix cleanup for mesh pathtable 2016-04-05 21:34:53 +02:00
michael.c
michael.h mac80211: fix some missing includes 2014-04-09 14:49:43 +02:00
mlme.c mac80211: remove disconnected APs from BSS table 2016-05-12 11:14:23 +02:00
ocb.c mac80211: remove rx_stats.last_rx update after sta alloc 2016-04-06 13:18:15 +02:00
offchannel.c mac80211: avoid ROC during hw restart 2016-01-14 11:10:14 +01:00
pm.c mac80211: don't reconfigure sched scan in case of wowlan 2015-11-03 10:42:05 +01:00
rate.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
rate.h mac80211: remove sta_info debugfs sub-struct 2016-04-05 11:59:05 +02:00
rc80211_minstrel_debugfs.c mac80211: minstrel[_ht]: remove non-ascii debugfs characters 2015-09-29 15:56:47 +02:00
rc80211_minstrel_ht_debugfs.c mac80211: minstrel[_ht]: remove non-ascii debugfs characters 2015-09-29 15:56:47 +02:00
rc80211_minstrel_ht.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
rc80211_minstrel_ht.h mac80211: add max lossless throughput per rate 2015-04-01 20:44:32 +02:00
rc80211_minstrel.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
rc80211_minstrel.h mac80211: add standard deviation to Minstrel stats 2015-04-01 20:44:33 +02:00
rx.c mac80211: allow software PS-Poll/U-APSD with AP_LINK_PS 2016-05-12 11:16:55 +02:00
scan.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
spectmgmt.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
sta_info.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-04-09 17:41:41 -04:00
sta_info.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-04-09 17:41:41 -04:00
status.c mac80211: add separate last_ack variable 2016-04-06 13:18:16 +02:00
tdls.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
tkip.c mac80211: move TKIP TX IVs to public part of key struct 2016-02-24 09:04:38 +01:00
tkip.h mac80211: move TKIP TX IVs to public part of key struct 2016-02-24 09:04:38 +01:00
trace_msg.h mac80211: Move message tracepoints to their own header 2015-04-07 12:32:09 -04:00
trace.c mac80211: Move message tracepoints to their own header 2015-04-07 12:32:09 -04:00
trace.h cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
tx.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
util.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
vht.c cfg80211: remove enum ieee80211_band 2016-04-12 15:56:15 +02:00
wep.c mac80211: move WEP tailroom size check 2015-05-11 14:51:29 +02:00
wep.h mac80211: move RX WEP weak IV counting 2012-03-13 14:54:16 -04:00
wme.c mac80211: synchronously reserve TID per station 2014-11-19 18:45:36 +01:00
wme.h mac80211: add WMM admission control support 2014-10-22 10:42:09 +02:00
wpa.c mac80211: allow same PN for AMSDU sub-frames 2016-05-12 11:14:45 +02:00
wpa.h mac80111: Add BIP-GMAC-128 and BIP-GMAC-256 ciphers 2015-01-27 11:10:13 +01:00