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[PATCH 3.10 38/56] net: call rcu_read_lock early in process_backlog

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 3.10 38/56] net: call rcu_read_lock early in process_backlog
Date 2015-09-29 16:00 +0200
Message-ID <qe3BP-8he-87@gated-at.bofh.it> (permalink)
References <qe3s5-85D-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Julian Anastasov <ja@ssi.bg>

[ Upstream commit 2c17d27c36dcce2b6bf689f41a46b9e909877c21 ]

Incoming packet should be either in backlog queue or
in RCU read-side section. Otherwise, the final sequence of
flush_backlog() and synchronize_net() may miss packets
that can run without device reference:

CPU 1                  CPU 2
                       skb->dev: no reference
                       process_backlog:__skb_dequeue
                       process_backlog:local_irq_enable

on_each_cpu for
flush_backlog =>       IPI(hardirq): flush_backlog
                       - packet not found in backlog

                       CPU delayed ...
synchronize_net
- no ongoing RCU
read-side sections

netdev_run_todo,
rcu_barrier: no
ongoing callbacks
                       __netif_receive_skb_core:rcu_read_lock
                       - too late
free dev
                       process packet for freed dev

Fixes: 6e583ce5242f ("net: eliminate refcounting in backlog queue")
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/core/dev.c |   29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3443,8 +3443,6 @@ static int __netif_receive_skb_core(stru
 
 	pt_prev = NULL;
 
-	rcu_read_lock();
-
 another_round:
 	skb->skb_iif = skb->dev->ifindex;
 
@@ -3454,7 +3452,7 @@ another_round:
 	    skb->protocol == cpu_to_be16(ETH_P_8021AD)) {
 		skb = vlan_untag(skb);
 		if (unlikely(!skb))
-			goto unlock;
+			goto out;
 	}
 
 #ifdef CONFIG_NET_CLS_ACT
@@ -3479,7 +3477,7 @@ skip_taps:
 #ifdef CONFIG_NET_CLS_ACT
 	skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
 	if (!skb)
-		goto unlock;
+		goto out;
 ncls:
 #endif
 
@@ -3494,7 +3492,7 @@ ncls:
 		if (vlan_do_receive(&skb))
 			goto another_round;
 		else if (unlikely(!skb))
-			goto unlock;
+			goto out;
 	}
 
 	rx_handler = rcu_dereference(skb->dev->rx_handler);
@@ -3506,7 +3504,7 @@ ncls:
 		switch (rx_handler(&skb)) {
 		case RX_HANDLER_CONSUMED:
 			ret = NET_RX_SUCCESS;
-			goto unlock;
+			goto out;
 		case RX_HANDLER_ANOTHER:
 			goto another_round;
 		case RX_HANDLER_EXACT:
@@ -3558,8 +3556,6 @@ drop:
 		ret = NET_RX_DROP;
 	}
 
-unlock:
-	rcu_read_unlock();
 out:
 	return ret;
 }
@@ -3606,29 +3602,30 @@ static int __netif_receive_skb(struct sk
  */
 int netif_receive_skb(struct sk_buff *skb)
 {
+	int ret;
+
 	net_timestamp_check(netdev_tstamp_prequeue, skb);
 
 	if (skb_defer_rx_timestamp(skb))
 		return NET_RX_SUCCESS;
 
+	rcu_read_lock();
+
 #ifdef CONFIG_RPS
 	if (static_key_false(&rps_needed)) {
 		struct rps_dev_flow voidflow, *rflow = &voidflow;
-		int cpu, ret;
-
-		rcu_read_lock();
-
-		cpu = get_rps_cpu(skb->dev, skb, &rflow);
+		int cpu = get_rps_cpu(skb->dev, skb, &rflow);
 
 		if (cpu >= 0) {
 			ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
 			rcu_read_unlock();
 			return ret;
 		}
-		rcu_read_unlock();
 	}
 #endif
-	return __netif_receive_skb(skb);
+	ret = __netif_receive_skb(skb);
+	rcu_read_unlock();
+	return ret;
 }
 EXPORT_SYMBOL(netif_receive_skb);
 
@@ -4038,8 +4035,10 @@ static int process_backlog(struct napi_s
 		unsigned int qlen;
 
 		while ((skb = __skb_dequeue(&sd->process_queue))) {
+			rcu_read_lock();
 			local_irq_enable();
 			__netif_receive_skb(skb);
+			rcu_read_unlock();
 			local_irq_disable();
 			input_queue_head_incr(sd);
 			if (++work >= quota) {


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Thread

[PATCH 3.10 00/56] 3.10.90-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
  [PATCH 3.10 01/56] unshare: Unsharing a thread does not require unsharing a vm Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
  [PATCH 3.10 04/56] mac80211: enable assoc check for mesh interfaces Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
  [PATCH 3.10 02/56] rtlwifi: rtl8192cu: Add new device ID Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
  [PATCH 3.10 17/56] NFS: nfs_set_pgio_error sometimes misses errors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
  [PATCH 3.10 25/56] IB/uverbs: reject invalid or unknown opcodes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
  [PATCH 3.10 40/56] net: Fix skb csum races when peeking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 43/56] isdn/gigaset: reset tty->receive_room when attaching ser_gigaset Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 55/56] vfs: Remove incorrect debugging WARN in prepend_path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 29/56] stmmac: fix check for phydev being open Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
    Re: [PATCH 3.10 29/56] stmmac: fix check for phydev being open Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2015-09-30 13:30 +0200
  [PATCH 3.10 49/56] ip6_gre: release cached dst on tunnel removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 27/56] IB/mlx4: Forbid using sysfs to change RoCE pkeys Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 31/56] sctp: fix ASCONF list handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 41/56] net: Fix skb_set_peeked use-after-free bug Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 32/56] vhost/scsi: potential memory corruption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 30/56] hfs,hfsplus: cache pages correctly between bnode_create and bnode_free Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 35/56] net/tipc: initialize security state for new connection socket Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 52/56] net/ipv6: Correct PIM6 mrt_lock handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 50/56] usbnet: Get EVENT_NO_RUNTIME_PM bit before it is cleared Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 44/56] ipv6: lock socket in ip6_datagram_connect() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 42/56] bridge: mdb: fix double add notification Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 33/56] x86: bpf_jit: fix compilation of large bpf programs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 37/56] net: pktgen: fix race between pktgen_thread_worker() and kthread_stop() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 45/56] bonding: fix destruction of bond with devices different from arphrd_ether Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 53/56] sctp: fix race on protocol/netns initialization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 47/56] netlink: dont hold mutex in rcu callback when releasing mmapd ring Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 36/56] bridge: mdb: zero out the local br_ip variable before use Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 48/56] rds: fix an integer overflow test in rds_info_getsockopt() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  Re: [PATCH 3.10 08/56] Input: synaptics - fix handling of disabling gesture mode Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-09-29 16:00 +0200
    Re: [PATCH 3.10 08/56] Input: synaptics - fix handling of disabling  gesture mode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:20 +0200
  [PATCH 3.10 56/56] Revert "iio: bmg160: IIO_BUFFER and IIO_TRIGGERED_BUFFER are required" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 38/56] net: call rcu_read_lock early in process_backlog Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 54/56] fib_rules: fix fib rule dumps across multiple skbs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 46/56] inet: frags: fix defragmented packets IP header for af_packet Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 34/56] ipv6: Make MLD packets to only be processed locally Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 51/56] ipv6: fix exthdrs offload registration in out_rt path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 39/56] net: Clone skb before setting peeked flag Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
  [PATCH 3.10 03/56] tg3: Fix temperature reporting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 22/56] md/raid10: always set reshape_safe when initializing reshape_position. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 18/56] parisc: Filter out spurious interrupts in PA-RISC irq handler Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 13/56] Add radeon suspend/resume quirk for HP Compaq dc5750. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 16/56] NFSv4: dont set SETATTR for O_RDONLY|O_EXCL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 20/56] fs: if a coredump already exists, unlink and recreate with O_EXCL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 08/56] Input: synaptics - fix handling of disabling gesture mode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 06/56] arm64: compat: fix vfp save/restore across signal handlers in big-endian Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 21/56] mmc: core: fix race condition in mmc_wait_data_done Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 24/56] hfs: fix B-tree corruption after insertion at position 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 19/56] vmscan: fix increasing nr_isolated incurred by putback unevictable pages Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 12/56] powerpc/rtas: Introduce rtas_get_sensor_fast() for IRQ handlers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 11/56] powerpc/mm: Fix pte_pagesize_index() crash on 4K w/64K hash Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 07/56] arm64: head.S: initialise mdcr_el2 in el2_setup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  [PATCH 3.10 26/56] IB/uverbs: Fix race between ib_uverbs_open and remove_one Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
  Re: [PATCH 3.10 00/56] 3.10.90-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2015-09-29 19:00 +0200
  Re: [PATCH 3.10 00/56] 3.10.90-stable review Guenter Roeck <linux@roeck-us.net> - 2015-09-29 23:20 +0200
  Re: [PATCH 3.10 00/56] 3.10.90-stable review Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-30 07:50 +0200

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