linux-stable.git/net, branch v4.6.5 Linux kernel stable tree af_unix: fix hard linked sockets on overlay 2016-07-27T15:42:16+00:00 Miklos Szeredi mszeredi@redhat.com 2016-05-20T20:13:45+00:00 d808791ed068f7dabcc54fe07f07636fa436ddbb commit eb0a4a47ae89aaa0674ab3180de6a162f3be2ddf upstream. Overlayfs uses separate inodes even in the case of hard links on the underlying filesystems. This is a problem for AF_UNIX socket implementation which indexes sockets based on the inode. This resulted in hard linked sockets not working. The fix is to use the real, underlying inode. Test case follows: -- ovl-sock-test.c -- #include <unistd.h> #include <err.h> #include <sys/socket.h> #include <sys/un.h> #define SOCK "test-sock" #define SOCK2 "test-sock2" int main(void) { int fd, fd2; struct sockaddr_un addr = { .sun_family = AF_UNIX, .sun_path = SOCK, }; struct sockaddr_un addr2 = { .sun_family = AF_UNIX, .sun_path = SOCK2, }; unlink(SOCK); unlink(SOCK2); if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) err(1, "socket"); if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1) err(1, "bind"); if (listen(fd, 0) == -1) err(1, "listen"); if (link(SOCK, SOCK2) == -1) err(1, "link"); if ((fd2 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) err(1, "socket"); if (connect(fd2, (struct sockaddr *) &addr2, sizeof(addr2)) == -1) err (1, "connect"); return 0; } ---- Reported-by: Alexander Morozov <alexandr.morozov@docker.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit eb0a4a47ae89aaa0674ab3180de6a162f3be2ddf upstream.

Overlayfs uses separate inodes even in the case of hard links on the
underlying filesystems.  This is a problem for AF_UNIX socket
implementation which indexes sockets based on the inode.  This resulted in
hard linked sockets not working.

The fix is to use the real, underlying inode.

Test case follows:

-- ovl-sock-test.c --
#include <unistd.h>
#include <err.h>
#include <sys/socket.h>
#include <sys/un.h>

#define SOCK "test-sock"
#define SOCK2 "test-sock2"

int main(void)
{
	int fd, fd2;
	struct sockaddr_un addr = {
		.sun_family = AF_UNIX,
		.sun_path = SOCK,
	};
	struct sockaddr_un addr2 = {
		.sun_family = AF_UNIX,
		.sun_path = SOCK2,
	};

	unlink(SOCK);
	unlink(SOCK2);
	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
		err(1, "socket");
	if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1)
		err(1, "bind");
	if (listen(fd, 0) == -1)
		err(1, "listen");
	if (link(SOCK, SOCK2) == -1)
		err(1, "link");
	if ((fd2 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
		err(1, "socket");
	if (connect(fd2, (struct sockaddr *) &addr2, sizeof(addr2)) == -1)
		err (1, "connect");
	return 0;
}
----

Reported-by: Alexander Morozov <alexandr.morozov@docker.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ipv6: Fix mem leak in rt6i_pcpu 2016-07-27T15:42:14+00:00 Martin KaFai Lau kafai@fb.com 2016-07-05T19:10:23+00:00 2ac4d627cd27cfee683add65ad972de71e4df5c1 [ Upstream commit 903ce4abdf374e3365d93bcb3df56c62008835ba ] It was first reported and reproduced by Petr (thanks!) in https://bugzilla.kernel.org/show_bug.cgi?id=119581 free_percpu(rt->rt6i_pcpu) used to always happen in ip6_dst_destroy(). However, after fixing a deadlock bug in commit 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt"), free_percpu() is not called before setting non_pcpu_rt->rt6i_pcpu to NULL. It is worth to note that rt6i_pcpu is protected by table->tb6_lock. kmemleak somehow did not report it. We nailed it down by observing the pcpu entries in /proc/vmallocinfo (first suggested by Hannes, thanks!). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Fixes: 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt") Reported-by: Petr Novopashenniy <pety@rusnet.ru> Tested-by: Petr Novopashenniy <pety@rusnet.ru> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Petr Novopashenniy <pety@rusnet.ru> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 903ce4abdf374e3365d93bcb3df56c62008835ba ]

It was first reported and reproduced by Petr (thanks!) in
https://bugzilla.kernel.org/show_bug.cgi?id=119581

free_percpu(rt->rt6i_pcpu) used to always happen in ip6_dst_destroy().

However, after fixing a deadlock bug in
commit 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt"),
free_percpu() is not called before setting non_pcpu_rt->rt6i_pcpu to NULL.

It is worth to note that rt6i_pcpu is protected by table->tb6_lock.

kmemleak somehow did not report it.  We nailed it down by
observing the pcpu entries in /proc/vmallocinfo (first suggested
by Hannes, thanks!).

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Fixes: 9c7370a166b4 ("ipv6: Fix a potential deadlock when creating pcpu rt")
Reported-by: Petr Novopashenniy <pety@rusnet.ru>
Tested-by: Petr Novopashenniy <pety@rusnet.ru>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Petr Novopashenniy <pety@rusnet.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net_sched: fix mirrored packets checksum 2016-07-27T15:42:13+00:00 WANG Cong xiyou.wangcong@gmail.com 2016-06-30T17:15:22+00:00 49729eccc9d7ef545d484fe3d277697fa2701840 [ Upstream commit 82a31b9231f02d9c1b7b290a46999d517b0d312a ] Similar to commit 9b368814b336 ("net: fix bridge multicast packet checksum validation") we need to fixup the checksum for CHECKSUM_COMPLETE when pushing skb on RX path. Otherwise we get similar splats. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Tom Herbert <tom@herbertland.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 82a31b9231f02d9c1b7b290a46999d517b0d312a ]

Similar to commit 9b368814b336 ("net: fix bridge multicast packet checksum validation")
we need to fixup the checksum for CHECKSUM_COMPLETE when
pushing skb on RX path. Otherwise we get similar splats.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
packet: Use symmetric hash for PACKET_FANOUT_HASH. 2016-07-27T15:42:13+00:00 David S. Miller davem@davemloft.net 2016-07-01T20:07:50+00:00 74a601e604a228bacdb79323ec9667756eb3e162 [ Upstream commit eb70db8756717b90c01ccc765fdefc4dd969fc74 ] People who use PACKET_FANOUT_HASH want a symmetric hash, meaning that they want packets going in both directions on a flow to hash to the same bucket. The core kernel SKB hash became non-symmetric when the ipv6 flow label and other entities were incorporated into the standard flow hash order to increase entropy. But there are no users of PACKET_FANOUT_HASH who want an assymetric hash, they all want a symmetric one. Therefore, use the flow dissector to compute a flat symmetric hash over only the protocol, addresses and ports. This hash does not get installed into and override the normal skb hash, so this change has no effect whatsoever on the rest of the stack. Reported-by: Eric Leblond <eric@regit.org> Tested-by: Eric Leblond <eric@regit.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit eb70db8756717b90c01ccc765fdefc4dd969fc74 ]

People who use PACKET_FANOUT_HASH want a symmetric hash, meaning that
they want packets going in both directions on a flow to hash to the
same bucket.

The core kernel SKB hash became non-symmetric when the ipv6 flow label
and other entities were incorporated into the standard flow hash order
to increase entropy.

But there are no users of PACKET_FANOUT_HASH who want an assymetric
hash, they all want a symmetric one.

Therefore, use the flow dissector to compute a flat symmetric hash
over only the protocol, addresses and ports.  This hash does not get
installed into and override the normal skb hash, so this change has
no effect whatsoever on the rest of the stack.

Reported-by: Eric Leblond <eric@regit.org>
Tested-by: Eric Leblond <eric@regit.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rpc: share one xps between all backchannels 2016-07-27T15:42:12+00:00 J. Bruce Fields bfields@redhat.com 2016-05-17T16:38:21+00:00 ea22632f041a5f6e436ea308aaf7d84aaa6009b1 commit 39a9beab5acb83176e8b9a4f0778749a09341f1f upstream. The spec allows backchannels for multiple clients to share the same tcp connection. When that happens, we need to use the same xprt for all of them. Similarly, we need the same xps. This fixes list corruption introduced by the multipath code. Signed-off-by: J. Bruce Fields <bfields@redhat.com> Acked-by: Trond Myklebust <trondmy@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 39a9beab5acb83176e8b9a4f0778749a09341f1f upstream.

The spec allows backchannels for multiple clients to share the same tcp
connection.  When that happens, we need to use the same xprt for all of
them.  Similarly, we need the same xps.

This fixes list corruption introduced by the multipath code.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
SUNRPC: fix xprt leak on xps allocation failure 2016-07-27T15:42:12+00:00 J. Bruce Fields bfields@redhat.com 2016-05-20T21:07:17+00:00 863af7a779f0f0b6f2d49d32c8c23f4dd68507e5 commit 1208fd569c07ab84aa5d024abd863267c2953b4a upstream. Callers of rpc_create_xprt expect it to put the xprt on success and failure. Signed-off-by: J. Bruce Fields <bfields@redhat.com> Acked-by: Trond Myklebust <trondmy@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1208fd569c07ab84aa5d024abd863267c2953b4a upstream.

Callers of rpc_create_xprt expect it to put the xprt on success and
failure.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nfsd4/rpc: move backchannel create logic into rpc code 2016-07-27T15:42:11+00:00 J. Bruce Fields bfields@redhat.com 2016-05-16T21:03:42+00:00 2de09ffe78ed319167f329f79dcefae32221fd55 commit d50039ea5ee63c589b0434baa5ecf6e5075bb6f9 upstream. Also simplify the logic a bit. Signed-off-by: J. Bruce Fields <bfields@redhat.com> Acked-by: Trond Myklebust <trondmy@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d50039ea5ee63c589b0434baa5ecf6e5075bb6f9 upstream.

Also simplify the logic a bit.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cfg80211: fix proto in ieee80211_data_to_8023 for frames without LLC header 2016-07-27T15:42:07+00:00 Felix Fietkau nbd@nbd.name 2016-06-29T08:36:39+00:00 ac2b80507d990bcc2d682cc1506741afcbcf2904 commit c041778c966c92c964033f1cdfee60a9f2b5e465 upstream. The PDU length of incoming LLC frames is set to the total skb payload size in __ieee80211_data_to_8023() of net/wireless/util.c which incorrectly includes the length of the IEEE 802.11 header. The resulting LLC frame header has a too large PDU length, causing the llc_fixup_skb() function of net/llc/llc_input.c to reject the incoming skb, effectively breaking STP. Solve the problem by properly substracting the IEEE 802.11 frame header size from the PDU length, allowing the LLC processor to pick up the incoming control messages. Special thanks to Gerry Rozema for tracking down the regression and proposing a suitable patch. Fixes: 2d1c304cb2d5 ("cfg80211: add function for 802.3 conversion with separate output buffer") Reported-by: Gerry Rozema <gerryr@rozeware.com> Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c041778c966c92c964033f1cdfee60a9f2b5e465 upstream.

The PDU length of incoming LLC frames is set to the total skb payload size
in __ieee80211_data_to_8023() of net/wireless/util.c which incorrectly
includes the length of the IEEE 802.11 header.

The resulting LLC frame header has a too large PDU length, causing the
llc_fixup_skb() function of net/llc/llc_input.c to reject the incoming
skb, effectively breaking STP.

Solve the problem by properly substracting the IEEE 802.11 frame header size
from the PDU length, allowing the LLC processor to pick up the incoming
control messages.

Special thanks to Gerry Rozema for tracking down the regression and proposing
a suitable patch.

Fixes: 2d1c304cb2d5 ("cfg80211: add function for 802.3 conversion with separate output buffer")
Reported-by: Gerry Rozema <gerryr@rozeware.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mac80211: Fix mesh estab_plinks counting in STA removal case 2016-07-27T15:42:07+00:00 Jouni Malinen j@w1.fi 2016-06-19T20:51:02+00:00 18c1df61dd764c2dcd97a90af91ac5a64ad95fd6 commit 126e7557328a1cd576be4fca95b133a2695283ff upstream. If a user space program (e.g., wpa_supplicant) deletes a STA entry that is currently in NL80211_PLINK_ESTAB state, the number of established plinks counter was not decremented and this could result in rejecting new plink establishment before really hitting the real maximum plink limit. For !user_mpm case, this decrementation is handled by mesh_plink_deactive(). Fix this by decrementing estab_plinks on STA deletion (mesh_sta_cleanup() gets called from there) so that the counter has a correct value and the Beacon frame advertisement in Mesh Configuration element shows the proper value for capability to accept additional peers. Signed-off-by: Jouni Malinen <j@w1.fi> Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 126e7557328a1cd576be4fca95b133a2695283ff upstream.

If a user space program (e.g., wpa_supplicant) deletes a STA entry that
is currently in NL80211_PLINK_ESTAB state, the number of established
plinks counter was not decremented and this could result in rejecting
new plink establishment before really hitting the real maximum plink
limit. For !user_mpm case, this decrementation is handled by
mesh_plink_deactive().

Fix this by decrementing estab_plinks on STA deletion
(mesh_sta_cleanup() gets called from there) so that the counter has a
correct value and the Beacon frame advertisement in Mesh Configuration
element shows the proper value for capability to accept additional
peers.

Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mac80211: mesh: flush mesh paths unconditionally 2016-07-27T15:42:07+00:00 Bob Copeland me@bobcopeland.com 2016-05-15T17:19:16+00:00 a7db982a262e939e687b014b1c501e701d085578 commit fe7a7c57629e8dcbc0e297363a9b2366d67a6dc5 upstream. 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 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit fe7a7c57629e8dcbc0e297363a9b2366d67a6dc5 upstream.

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

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>