[PATCH AUTOSEL 4.9 09/20] sch_netem: fix rcu splat in netem_enqueue()

[PATCH AUTOSEL 4.9 09/20] sch_netem: fix rcu splat in netem_enqueue()

[Sasha Levin]

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 159d2c7d8106177bd9a986fd005a311fe0d11285 ]

qdisc_root() use from netem_enqueue() triggers a lockdep warning.

__dev_queue_xmit() uses rcu_read_lock_bh() which is
not equivalent to rcu_read_lock() + local_bh_disable_bh as far
as lockdep is concerned.

WARNING: suspicious RCU usage
5.3.0-rc7+ #0 Not tainted
-----------------------------
include/net/sch_generic.h:492 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syz-executor427/8855:
 #0: 00000000b5525c01 (rcu_read_lock_bh){....}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline]
 #0: 00000000b5525c01 (rcu_read_lock_bh){....}, at: ip_finish_output2+0x2dc/0x2570 net/ipv4/ip_output.c:214
 #1: 00000000b5525c01 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x3650 net/core/dev.c:3804
 #2: 00000000364bae92 (&(&sch->q.lock)->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline]
 #2: 00000000364bae92 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_xmit_skb net/core/dev.c:3502 [inline]
 #2: 00000000364bae92 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_queue_xmit+0x14b8/0x3650 net/core/dev.c:3838

stack backtrace:
CPU: 0 PID: 8855 Comm: syz-executor427 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5357
 qdisc_root include/net/sch_generic.h:492 [inline]
 netem_enqueue+0x1cfb/0x2d80 net/sched/sch_netem.c:479
 __dev_xmit_skb net/core/dev.c:3527 [inline]
 __dev_queue_xmit+0x15d2/0x3650 net/core/dev.c:3838
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902
 neigh_hh_output include/net/neighbour.h:500 [inline]
 neigh_output include/net/neighbour.h:509 [inline]
 ip_finish_output2+0x1726/0x2570 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:308 [inline]
 __ip_finish_output+0x5fc/0xb90 net/ipv4/ip_output.c:290
 ip_finish_output+0x38/0x1f0 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip_mc_output+0x292/0xf40 net/ipv4/ip_output.c:417
 dst_output include/net/dst.h:436 [inline]
 ip_local_out+0xbb/0x190 net/ipv4/ip_output.c:125
 ip_send_skb+0x42/0xf0 net/ipv4/ip_output.c:1555
 udp_send_skb.isra.0+0x6b2/0x1160 net/ipv4/udp.c:887
 udp_sendmsg+0x1e96/0x2820 net/ipv4/udp.c:1174
 inet_sendmsg+0x9e/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:657
 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2311
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2439
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/sch_generic.h | 5 +++++
 net/sched/sch_netem.c     | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 538f3c4458b04..5d5a137b9067f 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -276,6 +276,11 @@ static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
 	return q;
 }
 
+static inline struct Qdisc *qdisc_root_bh(const struct Qdisc *qdisc)
+{
+	return rcu_dereference_bh(qdisc->dev_queue->qdisc);
+}
+
 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
 {
 	return qdisc->dev_queue->qdisc_sleeping;
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 12e3ae09c4ba1..95002e56fa48b 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -475,7 +475,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	 * skb will be queued.
 	 */
 	if (count > 1 && (skb2 = skb_clone(skb, GFP_ATOMIC)) != NULL) {
-		struct Qdisc *rootq = qdisc_root(sch);
+		struct Qdisc *rootq = qdisc_root_bh(sch);
 		u32 dupsave = q->duplicate; /* prevent duplicating a dup... */
 
 		q->duplicate = 0;
-- 
2.20.1

[PATCH AUTOSEL 4.9 10/20] llc: fix sk_buff leak in llc_sap_state_process()

[Sasha Levin]

From: Eric Biggers <ebiggers@google.com>

[ Upstream commit c6ee11c39fcc1fb55130748990a8f199e76263b4 ]

syzbot reported:

    BUG: memory leak
    unreferenced object 0xffff888116270800 (size 224):
       comm "syz-executor641", pid 7047, jiffies 4294947360 (age 13.860s)
       hex dump (first 32 bytes):
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
         00 20 e1 2a 81 88 ff ff 00 40 3d 2a 81 88 ff ff  . .*.....@=*....
       backtrace:
         [<000000004d41b4cc>] kmemleak_alloc_recursive  include/linux/kmemleak.h:55 [inline]
         [<000000004d41b4cc>] slab_post_alloc_hook mm/slab.h:439 [inline]
         [<000000004d41b4cc>] slab_alloc_node mm/slab.c:3269 [inline]
         [<000000004d41b4cc>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
         [<00000000506a5965>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
         [<000000001ba5a161>] alloc_skb include/linux/skbuff.h:1058 [inline]
         [<000000001ba5a161>] alloc_skb_with_frags+0x5f/0x250  net/core/skbuff.c:5327
         [<0000000047d9c78b>] sock_alloc_send_pskb+0x269/0x2a0  net/core/sock.c:2225
         [<000000003828fe54>] sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2242
         [<00000000e34d94f9>] llc_ui_sendmsg+0x10a/0x540 net/llc/af_llc.c:933
         [<00000000de2de3fb>] sock_sendmsg_nosec net/socket.c:652 [inline]
         [<00000000de2de3fb>] sock_sendmsg+0x54/0x70 net/socket.c:671
         [<000000008fe16e7a>] __sys_sendto+0x148/0x1f0 net/socket.c:1964
	 [...]

The bug is that llc_sap_state_process() always takes an extra reference
to the skb, but sometimes neither llc_sap_next_state() nor
llc_sap_state_process() itself drops this reference.

Fix it by changing llc_sap_next_state() to never consume a reference to
the skb, rather than sometimes do so and sometimes not.  Then remove the
extra skb_get() and kfree_skb() from llc_sap_state_process().

Reported-by: syzbot+6bf095f9becf5efef645@syzkaller.appspotmail.com
Reported-by: syzbot+31c16aa4202dace3812e@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/llc/llc_s_ac.c | 12 +++++++++---
 net/llc/llc_sap.c  | 23 ++++++++---------------
 2 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/net/llc/llc_s_ac.c b/net/llc/llc_s_ac.c
index a94bd56bcac6f..7ae4cc684d3ab 100644
--- a/net/llc/llc_s_ac.c
+++ b/net/llc/llc_s_ac.c
@@ -58,8 +58,10 @@ int llc_sap_action_send_ui(struct llc_sap *sap, struct sk_buff *skb)
 			    ev->daddr.lsap, LLC_PDU_CMD);
 	llc_pdu_init_as_ui_cmd(skb);
 	rc = llc_mac_hdr_init(skb, ev->saddr.mac, ev->daddr.mac);
-	if (likely(!rc))
+	if (likely(!rc)) {
+		skb_get(skb);
 		rc = dev_queue_xmit(skb);
+	}
 	return rc;
 }
 
@@ -81,8 +83,10 @@ int llc_sap_action_send_xid_c(struct llc_sap *sap, struct sk_buff *skb)
 			    ev->daddr.lsap, LLC_PDU_CMD);
 	llc_pdu_init_as_xid_cmd(skb, LLC_XID_NULL_CLASS_2, 0);
 	rc = llc_mac_hdr_init(skb, ev->saddr.mac, ev->daddr.mac);
-	if (likely(!rc))
+	if (likely(!rc)) {
+		skb_get(skb);
 		rc = dev_queue_xmit(skb);
+	}
 	return rc;
 }
 
@@ -135,8 +139,10 @@ int llc_sap_action_send_test_c(struct llc_sap *sap, struct sk_buff *skb)
 			    ev->daddr.lsap, LLC_PDU_CMD);
 	llc_pdu_init_as_test_cmd(skb);
 	rc = llc_mac_hdr_init(skb, ev->saddr.mac, ev->daddr.mac);
-	if (likely(!rc))
+	if (likely(!rc)) {
+		skb_get(skb);
 		rc = dev_queue_xmit(skb);
+	}
 	return rc;
 }
 
diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
index 5404d0d195cc5..d51ff9df9c959 100644
--- a/net/llc/llc_sap.c
+++ b/net/llc/llc_sap.c
@@ -197,29 +197,22 @@ static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
  *	After executing actions of the event, upper layer will be indicated
  *	if needed(on receiving an UI frame). sk can be null for the
  *	datalink_proto case.
+ *
+ *	This function always consumes a reference to the skb.
  */
 static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
 {
 	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
 
-	/*
-	 * We have to hold the skb, because llc_sap_next_state
-	 * will kfree it in the sending path and we need to
-	 * look at the skb->cb, where we encode llc_sap_state_ev.
-	 */
-	skb_get(skb);
 	ev->ind_cfm_flag = 0;
 	llc_sap_next_state(sap, skb);
-	if (ev->ind_cfm_flag == LLC_IND) {
-		if (skb->sk->sk_state == TCP_LISTEN)
-			kfree_skb(skb);
-		else {
-			llc_save_primitive(skb->sk, skb, ev->prim);
 
-			/* queue skb to the user. */
-			if (sock_queue_rcv_skb(skb->sk, skb))
-				kfree_skb(skb);
-		}
+	if (ev->ind_cfm_flag == LLC_IND && skb->sk->sk_state != TCP_LISTEN) {
+		llc_save_primitive(skb->sk, skb, ev->prim);
+
+		/* queue skb to the user. */
+		if (sock_queue_rcv_skb(skb->sk, skb) == 0)
+			return;
 	}
 	kfree_skb(skb);
 }
-- 
2.20.1

[PATCH AUTOSEL 4.9 11/20] llc: fix sk_buff leak in llc_conn_service()

[Sasha Levin]

From: Eric Biggers <ebiggers@google.com>

[ Upstream commit b74555de21acd791f12c4a1aeaf653dd7ac21133 ]

syzbot reported:

    BUG: memory leak
    unreferenced object 0xffff88811eb3de00 (size 224):
       comm "syz-executor559", pid 7315, jiffies 4294943019 (age 10.300s)
       hex dump (first 32 bytes):
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
         00 a0 38 24 81 88 ff ff 00 c0 f2 15 81 88 ff ff  ..8$............
       backtrace:
         [<000000008d1c66a1>] kmemleak_alloc_recursive  include/linux/kmemleak.h:55 [inline]
         [<000000008d1c66a1>] slab_post_alloc_hook mm/slab.h:439 [inline]
         [<000000008d1c66a1>] slab_alloc_node mm/slab.c:3269 [inline]
         [<000000008d1c66a1>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
         [<00000000447d9496>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
         [<000000000cdbf82f>] alloc_skb include/linux/skbuff.h:1058 [inline]
         [<000000000cdbf82f>] llc_alloc_frame+0x66/0x110 net/llc/llc_sap.c:54
         [<000000002418b52e>] llc_conn_ac_send_sabme_cmd_p_set_x+0x2f/0x140  net/llc/llc_c_ac.c:777
         [<000000001372ae17>] llc_exec_conn_trans_actions net/llc/llc_conn.c:475  [inline]
         [<000000001372ae17>] llc_conn_service net/llc/llc_conn.c:400 [inline]
         [<000000001372ae17>] llc_conn_state_process+0x1ac/0x640  net/llc/llc_conn.c:75
         [<00000000f27e53c1>] llc_establish_connection+0x110/0x170  net/llc/llc_if.c:109
         [<00000000291b2ca0>] llc_ui_connect+0x10e/0x370 net/llc/af_llc.c:477
         [<000000000f9c740b>] __sys_connect+0x11d/0x170 net/socket.c:1840
         [...]

The bug is that most callers of llc_conn_send_pdu() assume it consumes a
reference to the skb, when actually due to commit b85ab56c3f81 ("llc:
properly handle dev_queue_xmit() return value") it doesn't.

Revert most of that commit, and instead make the few places that need
llc_conn_send_pdu() to *not* consume a reference call skb_get() before.

Fixes: b85ab56c3f81 ("llc: properly handle dev_queue_xmit() return value")
Reported-by: syzbot+6b825a6494a04cc0e3f7@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/llc_conn.h |  2 +-
 net/llc/llc_c_ac.c     |  8 ++++++--
 net/llc/llc_conn.c     | 32 +++++++++-----------------------
 3 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/include/net/llc_conn.h b/include/net/llc_conn.h
index df528a6235487..ea985aa7a6c5e 100644
--- a/include/net/llc_conn.h
+++ b/include/net/llc_conn.h
@@ -104,7 +104,7 @@ void llc_sk_reset(struct sock *sk);
 
 /* Access to a connection */
 int llc_conn_state_process(struct sock *sk, struct sk_buff *skb);
-int llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb);
+void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb);
 void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb);
 void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit);
 void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit);
diff --git a/net/llc/llc_c_ac.c b/net/llc/llc_c_ac.c
index 4b60f68cb4925..8354ae40ec85b 100644
--- a/net/llc/llc_c_ac.c
+++ b/net/llc/llc_c_ac.c
@@ -372,6 +372,7 @@ int llc_conn_ac_send_i_cmd_p_set_1(struct sock *sk, struct sk_buff *skb)
 	llc_pdu_init_as_i_cmd(skb, 1, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
+		skb_get(skb);
 		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
@@ -389,7 +390,8 @@ static int llc_conn_ac_send_i_cmd_p_set_0(struct sock *sk, struct sk_buff *skb)
 	llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
-		rc = llc_conn_send_pdu(sk, skb);
+		skb_get(skb);
+		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
 	return rc;
@@ -406,6 +408,7 @@ int llc_conn_ac_send_i_xxx_x_set_0(struct sock *sk, struct sk_buff *skb)
 	llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
+		skb_get(skb);
 		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
@@ -916,7 +919,8 @@ static int llc_conn_ac_send_i_rsp_f_set_ackpf(struct sock *sk,
 	llc_pdu_init_as_i_cmd(skb, llc->ack_pf, llc->vS, llc->vR);
 	rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac);
 	if (likely(!rc)) {
-		rc = llc_conn_send_pdu(sk, skb);
+		skb_get(skb);
+		llc_conn_send_pdu(sk, skb);
 		llc_conn_ac_inc_vs_by_1(sk, skb);
 	}
 	return rc;
diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c
index b9290a183a2fd..94c78cc49d3e0 100644
--- a/net/llc/llc_conn.c
+++ b/net/llc/llc_conn.c
@@ -30,7 +30,7 @@
 #endif
 
 static int llc_find_offset(int state, int ev_type);
-static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *skb);
+static void llc_conn_send_pdus(struct sock *sk);
 static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
 static int llc_exec_conn_trans_actions(struct sock *sk,
 				       struct llc_conn_state_trans *trans,
@@ -193,11 +193,11 @@ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
 	return rc;
 }
 
-int llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
+void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
 {
 	/* queue PDU to send to MAC layer */
 	skb_queue_tail(&sk->sk_write_queue, skb);
-	return llc_conn_send_pdus(sk, skb);
+	llc_conn_send_pdus(sk);
 }
 
 /**
@@ -255,7 +255,7 @@ void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
 	if (howmany_resend > 0)
 		llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
 	/* any PDUs to re-send are queued up; start sending to MAC */
-	llc_conn_send_pdus(sk, NULL);
+	llc_conn_send_pdus(sk);
 out:;
 }
 
@@ -296,7 +296,7 @@ void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
 	if (howmany_resend > 0)
 		llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
 	/* any PDUs to re-send are queued up; start sending to MAC */
-	llc_conn_send_pdus(sk, NULL);
+	llc_conn_send_pdus(sk);
 out:;
 }
 
@@ -340,16 +340,12 @@ int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
 /**
  *	llc_conn_send_pdus - Sends queued PDUs
  *	@sk: active connection
- *	@hold_skb: the skb held by caller, or NULL if does not care
  *
- *	Sends queued pdus to MAC layer for transmission. When @hold_skb is
- *	NULL, always return 0. Otherwise, return 0 if @hold_skb is sent
- *	successfully, or 1 for failure.
+ *	Sends queued pdus to MAC layer for transmission.
  */
-static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *hold_skb)
+static void llc_conn_send_pdus(struct sock *sk)
 {
 	struct sk_buff *skb;
-	int ret = 0;
 
 	while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
 		struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
@@ -361,20 +357,10 @@ static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *hold_skb)
 			skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
 			if (!skb2)
 				break;
-			dev_queue_xmit(skb2);
-		} else {
-			bool is_target = skb == hold_skb;
-			int rc;
-
-			if (is_target)
-				skb_get(skb);
-			rc = dev_queue_xmit(skb);
-			if (is_target)
-				ret = rc;
+			skb = skb2;
 		}
+		dev_queue_xmit(skb);
 	}
-
-	return ret;
 }
 
 /**
-- 
2.20.1

[PATCH AUTOSEL 4.9 12/20] bonding: fix potential NULL deref in bond_update_slave_arr

[Sasha Levin]

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit a7137534b597b7c303203e6bc3ed87e87a273bb8 ]

syzbot got a NULL dereference in bond_update_slave_arr() [1],
happening after a failure to allocate bond->slave_arr

A workqueue (bond_slave_arr_handler) is supposed to retry
the allocation later, but if the slave is removed before
the workqueue had a chance to complete, bond->slave_arr
can still be NULL.

[1]

Failed to build slave-array.
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN PTI
Modules linked in:
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bond_update_slave_arr.cold+0xc6/0x198 drivers/net/bonding/bond_main.c:4039
RSP: 0018:ffff88018fe33678 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000290b000
RDX: 0000000000000000 RSI: ffffffff82b63037 RDI: ffff88019745ea20
RBP: ffff88018fe33760 R08: ffff880170754280 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88019745ea00 R14: 0000000000000000 R15: ffff88018fe338b0
FS:  00007febd837d700(0000) GS:ffff8801dad00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004540a0 CR3: 00000001c242e005 CR4: 00000000001626f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 [<ffffffff82b5b45e>] __bond_release_one+0x43e/0x500 drivers/net/bonding/bond_main.c:1923
 [<ffffffff82b5b966>] bond_release drivers/net/bonding/bond_main.c:2039 [inline]
 [<ffffffff82b5b966>] bond_do_ioctl+0x416/0x870 drivers/net/bonding/bond_main.c:3562
 [<ffffffff83ae25f4>] dev_ifsioc+0x6f4/0x940 net/core/dev_ioctl.c:328
 [<ffffffff83ae2e58>] dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:495
 [<ffffffff83995ffd>] sock_do_ioctl+0x1bd/0x300 net/socket.c:1088
 [<ffffffff83996a80>] sock_ioctl+0x300/0x5d0 net/socket.c:1196
 [<ffffffff81b124db>] vfs_ioctl fs/ioctl.c:47 [inline]
 [<ffffffff81b124db>] file_ioctl fs/ioctl.c:501 [inline]
 [<ffffffff81b124db>] do_vfs_ioctl+0xacb/0x1300 fs/ioctl.c:688
 [<ffffffff81b12dc6>] SYSC_ioctl fs/ioctl.c:705 [inline]
 [<ffffffff81b12dc6>] SyS_ioctl+0xb6/0xe0 fs/ioctl.c:696
 [<ffffffff8101ccc8>] do_syscall_64+0x528/0x770 arch/x86/entry/common.c:305
 [<ffffffff84400091>] entry_SYSCALL_64_after_hwframe+0x42/0xb7

Fixes: ee6377147409 ("bonding: Simplify the xmit function for modes that use xmit_hash")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/bonding/bond_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 8820fb1aec5b4..c1971bca62fb1 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3963,7 +3963,7 @@ int bond_update_slave_arr(struct bonding *bond, struct slave *skipslave)
 		 * this to-be-skipped slave to send a packet out.
 		 */
 		old_arr = rtnl_dereference(bond->slave_arr);
-		for (idx = 0; idx < old_arr->count; idx++) {
+		for (idx = 0; old_arr != NULL && idx < old_arr->count; idx++) {
 			if (skipslave == old_arr->arr[idx]) {
 				old_arr->arr[idx] =
 				    old_arr->arr[old_arr->count-1];
-- 
2.20.1

[PATCH AUTOSEL 4.9 13/20] net: usb: sr9800: fix uninitialized local variable

[Sasha Levin]

From: Valentin Vidic <vvidic@valentin-vidic.from.hr>

[ Upstream commit 77b6d09f4ae66d42cd63b121af67780ae3d1a5e9 ]

Make sure res does not contain random value if the call to
sr_read_cmd fails for some reason.

Reported-by: syzbot+f1842130bbcfb335bac1@syzkaller.appspotmail.com
Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/sr9800.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/sr9800.c b/drivers/net/usb/sr9800.c
index 004c955c1fd1b..da0ae16f5c74c 100644
--- a/drivers/net/usb/sr9800.c
+++ b/drivers/net/usb/sr9800.c
@@ -336,7 +336,7 @@ static void sr_set_multicast(struct net_device *net)
 static int sr_mdio_read(struct net_device *net, int phy_id, int loc)
 {
 	struct usbnet *dev = netdev_priv(net);
-	__le16 res;
+	__le16 res = 0;
 
 	mutex_lock(&dev->phy_mutex);
 	sr_set_sw_mii(dev);
-- 
2.20.1

[PATCH AUTOSEL 4.9 15/20] ath9k: dynack: fix possible deadlock in ath_dynack_node_{de}init

[Sasha Levin]

From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit e1aa1a1db3b01c9890e82cf065cee99962ba1ed9 ]

Fix following lockdep warning disabling bh in
ath_dynack_node_init/ath_dynack_node_deinit

[   75.955878] --------------------------------
[   75.955880] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   75.955884] swapper/0/0 [HC0[0]:SC1[3]:HE1:SE0] takes:
[   75.955888] 00000000792a7ee0 (&(&da->qlock)->rlock){+.?.}, at: ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.955905] {SOFTIRQ-ON-W} state was registered at:
[   75.955912]   lock_acquire+0x9a/0x160
[   75.955917]   _raw_spin_lock+0x2c/0x70
[   75.955927]   ath_dynack_node_init+0x2a/0x60 [ath9k_hw]
[   75.955934]   ath9k_sta_state+0xec/0x160 [ath9k]
[   75.955976]   drv_sta_state+0xb2/0x740 [mac80211]
[   75.956008]   sta_info_insert_finish+0x21a/0x420 [mac80211]
[   75.956039]   sta_info_insert_rcu+0x12b/0x2c0 [mac80211]
[   75.956069]   sta_info_insert+0x7/0x70 [mac80211]
[   75.956093]   ieee80211_prep_connection+0x42e/0x730 [mac80211]
[   75.956120]   ieee80211_mgd_auth.cold+0xb9/0x15c [mac80211]
[   75.956152]   cfg80211_mlme_auth+0x143/0x350 [cfg80211]
[   75.956169]   nl80211_authenticate+0x25e/0x2b0 [cfg80211]
[   75.956172]   genl_family_rcv_msg+0x198/0x400
[   75.956174]   genl_rcv_msg+0x42/0x90
[   75.956176]   netlink_rcv_skb+0x35/0xf0
[   75.956178]   genl_rcv+0x1f/0x30
[   75.956180]   netlink_unicast+0x154/0x200
[   75.956182]   netlink_sendmsg+0x1bf/0x3d0
[   75.956186]   ___sys_sendmsg+0x2c2/0x2f0
[   75.956187]   __sys_sendmsg+0x44/0x80
[   75.956190]   do_syscall_64+0x55/0x1a0
[   75.956192]   entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   75.956194] irq event stamp: 2357092
[   75.956196] hardirqs last  enabled at (2357092): [<ffffffff818c62de>] _raw_spin_unlock_irqrestore+0x3e/0x50
[   75.956199] hardirqs last disabled at (2357091): [<ffffffff818c60b1>] _raw_spin_lock_irqsave+0x11/0x80
[   75.956202] softirqs last  enabled at (2357072): [<ffffffff8106dc09>] irq_enter+0x59/0x60
[   75.956204] softirqs last disabled at (2357073): [<ffffffff8106dcbe>] irq_exit+0xae/0xc0
[   75.956206]
               other info that might help us debug this:
[   75.956207]  Possible unsafe locking scenario:

[   75.956208]        CPU0
[   75.956209]        ----
[   75.956210]   lock(&(&da->qlock)->rlock);
[   75.956213]   <Interrupt>
[   75.956214]     lock(&(&da->qlock)->rlock);
[   75.956216]
                *** DEADLOCK ***

[   75.956217] 1 lock held by swapper/0/0:
[   75.956219]  #0: 000000003bb5675c (&(&sc->sc_pcu_lock)->rlock){+.-.}, at: ath9k_tasklet+0x55/0x240 [ath9k]
[   75.956225]
               stack backtrace:
[   75.956228] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc1-wdn+ #13
[   75.956229] Hardware name: Dell Inc. Studio XPS 1340/0K183D, BIOS A11 09/08/2009
[   75.956231] Call Trace:
[   75.956233]  <IRQ>
[   75.956236]  dump_stack+0x67/0x90
[   75.956239]  mark_lock+0x4c1/0x640
[   75.956242]  ? check_usage_backwards+0x130/0x130
[   75.956245]  ? sched_clock_local+0x12/0x80
[   75.956247]  __lock_acquire+0x484/0x7a0
[   75.956250]  ? __lock_acquire+0x3b9/0x7a0
[   75.956252]  lock_acquire+0x9a/0x160
[   75.956259]  ? ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.956262]  _raw_spin_lock_bh+0x34/0x80
[   75.956268]  ? ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.956275]  ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.956280]  ath_rx_tasklet+0xd09/0xe90 [ath9k]
[   75.956286]  ath9k_tasklet+0x102/0x240 [ath9k]
[   75.956288]  tasklet_action_common.isra.0+0x6d/0x170
[   75.956291]  __do_softirq+0xcc/0x425
[   75.956294]  irq_exit+0xae/0xc0
[   75.956296]  do_IRQ+0x8a/0x110
[   75.956298]  common_interrupt+0xf/0xf
[   75.956300]  </IRQ>
[   75.956303] RIP: 0010:cpuidle_enter_state+0xb2/0x400
[   75.956308] RSP: 0018:ffffffff82203e70 EFLAGS: 00000202 ORIG_RAX: ffffffffffffffd7
[   75.956310] RAX: ffffffff82219800 RBX: ffffffff822bd0a0 RCX: 0000000000000000
[   75.956312] RDX: 0000000000000046 RSI: 0000000000000006 RDI: ffffffff82219800
[   75.956314] RBP: ffff888155a01c00 R08: 00000011af51aabe R09: 0000000000000000
[   75.956315] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
[   75.956317] R13: 00000011af51aabe R14: 0000000000000003 R15: ffffffff82219800
[   75.956321]  cpuidle_enter+0x24/0x40
[   75.956323]  do_idle+0x1ac/0x220
[   75.956326]  cpu_startup_entry+0x14/0x20
[   75.956329]  start_kernel+0x482/0x489
[   75.956332]  secondary_startup_64+0xa4/0xb0

Fixes: c774d57fd47c ("ath9k: add dynamic ACK timeout estimation")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/ath/ath9k/dynack.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/dynack.c b/drivers/net/wireless/ath/ath9k/dynack.c
index 6e236a4854311..71b4888b30e71 100644
--- a/drivers/net/wireless/ath/ath9k/dynack.c
+++ b/drivers/net/wireless/ath/ath9k/dynack.c
@@ -300,9 +300,9 @@ void ath_dynack_node_init(struct ath_hw *ah, struct ath_node *an)
 
 	an->ackto = ackto;
 
-	spin_lock(&da->qlock);
+	spin_lock_bh(&da->qlock);
 	list_add_tail(&an->list, &da->nodes);
-	spin_unlock(&da->qlock);
+	spin_unlock_bh(&da->qlock);
 }
 EXPORT_SYMBOL(ath_dynack_node_init);
 
@@ -316,9 +316,9 @@ void ath_dynack_node_deinit(struct ath_hw *ah, struct ath_node *an)
 {
 	struct ath_dynack *da = &ah->dynack;
 
-	spin_lock(&da->qlock);
+	spin_lock_bh(&da->qlock);
 	list_del(&an->list);
-	spin_unlock(&da->qlock);
+	spin_unlock_bh(&da->qlock);
 }
 EXPORT_SYMBOL(ath_dynack_node_deinit);
 
-- 
2.20.1

[PATCH AUTOSEL 4.9 19/20] ipv6: Handle race in addrconf_dad_work

[Sasha Levin]

From: David Ahern <dsahern@gmail.com>

[ Upstream commit a3ce2a21bb8969ae27917281244fa91bf5f286d7 ]

Rajendra reported a kernel panic when a link was taken down:

[ 6870.263084] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
[ 6870.271856] IP: [<ffffffff8efc5764>] __ipv6_ifa_notify+0x154/0x290

<snip>

[ 6870.570501] Call Trace:
[ 6870.573238] [<ffffffff8efc58c6>] ? ipv6_ifa_notify+0x26/0x40
[ 6870.579665] [<ffffffff8efc98ec>] ? addrconf_dad_completed+0x4c/0x2c0
[ 6870.586869] [<ffffffff8efe70c6>] ? ipv6_dev_mc_inc+0x196/0x260
[ 6870.593491] [<ffffffff8efc9c6a>] ? addrconf_dad_work+0x10a/0x430
[ 6870.600305] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.606732] [<ffffffff8ea93a7a>] ? process_one_work+0x18a/0x430
[ 6870.613449] [<ffffffff8ea93d6d>] ? worker_thread+0x4d/0x490
[ 6870.619778] [<ffffffff8ea93d20>] ? process_one_work+0x430/0x430
[ 6870.626495] [<ffffffff8ea99dd9>] ? kthread+0xd9/0xf0
[ 6870.632145] [<ffffffff8f01ade4>] ? __switch_to_asm+0x34/0x70
[ 6870.638573] [<ffffffff8ea99d00>] ? kthread_park+0x60/0x60
[ 6870.644707] [<ffffffff8f01ae77>] ? ret_from_fork+0x57/0x70
[ 6870.650936] Code: 31 c0 31 d2 41 b9 20 00 08 02 b9 09 00 00 0

addrconf_dad_work is kicked to be scheduled when a device is brought
up. There is a race between addrcond_dad_work getting scheduled and
taking the rtnl lock and a process taking the link down (under rtnl).
The latter removes the host route from the inet6_addr as part of
addrconf_ifdown which is run for NETDEV_DOWN. The former attempts
to use the host route in ipv6_ifa_notify. If the down event removes
the host route due to the race to the rtnl, then the BUG listed above
occurs.

This scenario does not occur when the ipv6 address is not kept
(net.ipv6.conf.all.keep_addr_on_down = 0) as addrconf_ifdown sets the
state of the ifp to DEAD. Handle when the addresses are kept by checking
IF_READY which is reset by addrconf_ifdown.

The 'dead' flag for an inet6_addr is set only under rtnl, in
addrconf_ifdown and it means the device is getting removed (or IPv6 is
disabled). The interesting cases for changing the idev flag are
addrconf_notify (NETDEV_UP and NETDEV_CHANGE) and addrconf_ifdown
(reset the flag). The former does not have the idev lock - only rtnl;
the latter has both. Based on that the existing dead + IF_READY check
can be moved to right after the rtnl_lock in addrconf_dad_work.

Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional")
Reported-by: Rajendra Dendukuri <rajendra.dendukuri@broadcom.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv6/addrconf.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6b1310d5e8087..61fd8ff922d97 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3859,6 +3859,12 @@ static void addrconf_dad_work(struct work_struct *w)
 
 	rtnl_lock();
 
+	/* check if device was taken down before this delayed work
+	 * function could be canceled
+	 */
+	if (idev->dead || !(idev->if_flags & IF_READY))
+		goto out;
+
 	spin_lock_bh(&ifp->lock);
 	if (ifp->state == INET6_IFADDR_STATE_PREDAD) {
 		action = DAD_BEGIN;
@@ -3902,11 +3908,6 @@ static void addrconf_dad_work(struct work_struct *w)
 		goto out;
 
 	write_lock_bh(&idev->lock);
-	if (idev->dead || !(idev->if_flags & IF_READY)) {
-		write_unlock_bh(&idev->lock);
-		goto out;
-	}
-
 	spin_lock(&ifp->lock);
 	if (ifp->state == INET6_IFADDR_STATE_DEAD) {
 		spin_unlock(&ifp->lock);
-- 
2.20.1

Re: [PATCH AUTOSEL 4.9 19/20] ipv6: Handle race in addrconf_dad_work

[David Ahern]

On 10/25/19 7:57 AM, Sasha Levin wrote:
> From: David Ahern <dsahern@gmail.com>
> 
> [ Upstream commit a3ce2a21bb8969ae27917281244fa91bf5f286d7 ]
> 

that patch was reverted in favor of a different solution. It should NOT
be backported to any releases.

Re: [PATCH AUTOSEL 4.9 19/20] ipv6: Handle race in addrconf_dad_work

[Sasha Levin]

On Fri, Oct 25, 2019 at 08:22:59AM -0600, David Ahern wrote:
>On 10/25/19 7:57 AM, Sasha Levin wrote:
>> From: David Ahern <dsahern@gmail.com>
>>
>> [ Upstream commit a3ce2a21bb8969ae27917281244fa91bf5f286d7 ]
>>
>
>that patch was reverted in favor of a different solution. It should NOT
>be backported to any releases.

I'll drop it, thank you.

-- 
Thanks,
Sasha