Eric Dumazet 518fbf9cdf net: fix sk_sockets_allocated_read_positive ... Denys Fedoryshchenko reported frequent crashes on a proxy server and kindly provided a lockdep report that explains it all : [ 762.903868] [ 762.903880] ================================= [ 762.903890] [ INFO: inconsistent lock state ] [ 762.903903] 3.3.4-build-0061 #8 Not tainted [ 762.904133] --------------------------------- [ 762.904344] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. [ 762.904542] squid/1603 [HC0[0]:SC0[0]:HE1:SE1] takes: [ 762.904542] (key#3){+.?...}, at: [<c0232cc4>] __percpu_counter_sum+0xd/0x58 [ 762.904542] {IN-SOFTIRQ-W} state was registered at: [ 762.904542] [<c0158b84>] __lock_acquire+0x284/0xc26 [ 762.904542] [<c01598e8>] lock_acquire+0x71/0x85 [ 762.904542] [<c0349765>] _raw_spin_lock+0x33/0x40 [ 762.904542] [<c0232c93>] __percpu_counter_add+0x58/0x7c [ 762.904542] [<c02cfde1>] sk_clone_lock+0x1e5/0x200 [ 762.904542] [<c0303ee4>] inet_csk_clone_lock+0xe/0x78 [ 762.904542] [<c0315778>] tcp_create_openreq_child+0x1b/0x404 [ 762.904542] [<c031339c>] tcp_v4_syn_recv_sock+0x32/0x1c1 [ 762.904542] [<c031615a>] tcp_check_req+0x1fd/0x2d7 [ 762.904542] [<c0313f77>] tcp_v4_do_rcv+0xab/0x194 [ 762.904542] [<c03153bb>] tcp_v4_rcv+0x3b3/0x5cc [ 762.904542] [<c02fc0c4>] ip_local_deliver_finish+0x13a/0x1e9 [ 762.904542] [<c02fc539>] NF_HOOK.clone.11+0x46/0x4d [ 762.904542] [<c02fc652>] ip_local_deliver+0x41/0x45 [ 762.904542] [<c02fc4d1>] ip_rcv_finish+0x31a/0x33c [ 762.904542] [<c02fc539>] NF_HOOK.clone.11+0x46/0x4d [ 762.904542] [<c02fc857>] ip_rcv+0x201/0x23e [ 762.904542] [<c02daa3a>] __netif_receive_skb+0x319/0x368 [ 762.904542] [<c02dac07>] netif_receive_skb+0x4e/0x7d [ 762.904542] [<c02dacf6>] napi_skb_finish+0x1e/0x34 [ 762.904542] [<c02db122>] napi_gro_receive+0x20/0x24 [ 762.904542] [<f85d1743>] e1000_receive_skb+0x3f/0x45 [e1000e] [ 762.904542] [<f85d3464>] e1000_clean_rx_irq+0x1f9/0x284 [e1000e] [ 762.904542] [<f85d3926>] e1000_clean+0x62/0x1f4 [e1000e] [ 762.904542] [<c02db228>] net_rx_action+0x90/0x160 [ 762.904542] [<c012a445>] __do_softirq+0x7b/0x118 [ 762.904542] irq event stamp: 156915469 [ 762.904542] hardirqs last enabled at (156915469): [<c019b4f4>] __slab_alloc.clone.58.clone.63+0xc4/0x2de [ 762.904542] hardirqs last disabled at (156915468): [<c019b452>] __slab_alloc.clone.58.clone.63+0x22/0x2de [ 762.904542] softirqs last enabled at (156915466): [<c02ce677>] lock_sock_nested+0x64/0x6c [ 762.904542] softirqs last disabled at (156915464): [<c0349914>] _raw_spin_lock_bh+0xe/0x45 [ 762.904542] [ 762.904542] other info that might help us debug this: [ 762.904542] Possible unsafe locking scenario: [ 762.904542] [ 762.904542] CPU0 [ 762.904542] ---- [ 762.904542] lock(key#3); [ 762.904542] <Interrupt> [ 762.904542] lock(key#3); [ 762.904542] [ 762.904542] *** DEADLOCK *** [ 762.904542] [ 762.904542] 1 lock held by squid/1603: [ 762.904542] #0: (sk_lock-AF_INET){+.+.+.}, at: [<c03055c0>] lock_sock+0xa/0xc [ 762.904542] [ 762.904542] stack backtrace: [ 762.904542] Pid: 1603, comm: squid Not tainted 3.3.4-build-0061 #8 [ 762.904542] Call Trace: [ 762.904542] [<c0347b73>] ? printk+0x18/0x1d [ 762.904542] [<c015873a>] valid_state+0x1f6/0x201 [ 762.904542] [<c0158816>] mark_lock+0xd1/0x1bb [ 762.904542] [<c015876b>] ? mark_lock+0x26/0x1bb [ 762.904542] [<c015805d>] ? check_usage_forwards+0x77/0x77 [ 762.904542] [<c0158bf8>] __lock_acquire+0x2f8/0xc26 [ 762.904542] [<c0159b8e>] ? mark_held_locks+0x5d/0x7b [ 762.904542] [<c0159cf6>] ? trace_hardirqs_on+0xb/0xd [ 762.904542] [<c0158dd4>] ? __lock_acquire+0x4d4/0xc26 [ 762.904542] [<c01598e8>] lock_acquire+0x71/0x85 [ 762.904542] [<c0232cc4>] ? __percpu_counter_sum+0xd/0x58 [ 762.904542] [<c0349765>] _raw_spin_lock+0x33/0x40 [ 762.904542] [<c0232cc4>] ? __percpu_counter_sum+0xd/0x58 [ 762.904542] [<c0232cc4>] __percpu_counter_sum+0xd/0x58 [ 762.904542] [<c02cebc4>] __sk_mem_schedule+0xdd/0x1c7 [ 762.904542] [<c02d178d>] ? __alloc_skb+0x76/0x100 [ 762.904542] [<c0305e8e>] sk_wmem_schedule+0x21/0x2d [ 762.904542] [<c0306370>] sk_stream_alloc_skb+0x42/0xaa [ 762.904542] [<c0306567>] tcp_sendmsg+0x18f/0x68b [ 762.904542] [<c031f3dc>] ? ip_fast_csum+0x30/0x30 [ 762.904542] [<c0320193>] inet_sendmsg+0x53/0x5a [ 762.904542] [<c02cb633>] sock_aio_write+0xd2/0xda [ 762.904542] [<c015876b>] ? mark_lock+0x26/0x1bb [ 762.904542] [<c01a1017>] do_sync_write+0x9f/0xd9 [ 762.904542] [<c01a2111>] ? file_free_rcu+0x2f/0x2f [ 762.904542] [<c01a17a1>] vfs_write+0x8f/0xab [ 762.904542] [<c01a284d>] ? fget_light+0x75/0x7c [ 762.904542] [<c01a1900>] sys_write+0x3d/0x5e [ 762.904542] [<c0349ec9>] syscall_call+0x7/0xb [ 762.904542] [<c0340000>] ? rp_sidt+0x41/0x83 Bug is that sk_sockets_allocated_read_positive() calls percpu_counter_sum_positive() without BH being disabled. This bug was added in commit 180d8cd942 (foundations of per-cgroup memory pressure controlling.), since previous code was using percpu_counter_read_positive() which is IRQ safe. In __sk_mem_schedule() we dont need the precise count of allocated sockets and can revert to previous behavior. Reported-by: Denys Fedoryshchenko <denys@visp.net.lb> Sined-off-by: Eric Dumazet <edumazet@google.com> Cc: Glauber Costa <glommer@parallels.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2012-04-30 13:37:59 -04:00
..
9p	9p: Reduce object size with CONFIG_NET_9P_DEBUG	2012-01-05 10:51:44 -06:00
bluetooth	Bluetooth: Fix userspace compatibility issue with mgmt interface	2012-04-05 15:05:51 -03:00
caif	caif-hsi: Add RX flip buffer	2012-02-04 16:06:28 -05:00
irda	Fix common misspellings	2011-03-31 11:26:23 -03:00
iucv	af_iucv: add shutdown for HS transport	2012-03-07 22:52:24 -08:00
netfilter	netfilter: xt_LOG: don't use xchg() for simple assignment	2012-03-26 14:00:28 +02:00
netns	BUG: headers with BUG/BUG_ON etc. need linux/bug.h	2012-03-04 17:54:34 -05:00
nfc	NFC: NCI code identation fixes	2012-03-06 15:16:25 -05:00
phonet	net: dont hold rtnl mutex during netlink dump callbacks	2011-05-02 15:26:28 -07:00
sctp	sctp: Export sctp_do_peeloff	2012-03-08 13:52:08 -08:00
tc_act
act_api.h	net: sched: constify tcf_proto and tc_action	2011-07-06 02:52:16 -07:00
addrconf.h	ipv6: Remove never used function inet6_ac_check().	2012-02-01 16:14:17 -05:00
af_ieee802154.h
af_rxrpc.h	net: Remove __KERNEL__ cpp checks from include/net	2011-04-24 10:54:56 -07:00
af_unix.h	switch unix_sock to struct path	2012-03-20 21:29:41 -04:00
ah.h	ipsec: update MAX_AH_AUTH_LEN to support sha512	2011-01-13 21:48:25 -08:00
arp.h	ipv4: Eliminate spurious argument to __ipv4_neigh_lookup	2012-02-15 17:48:35 -05:00
atmclip.h	atm: clip: Use device neigh support on top of "arp_tbl".	2011-11-30 18:51:03 -05:00
ax25.h	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
ax88796.h
cfg80211-wext.h	cfg80211: remove unused wext handler exports	2011-08-08 14:26:29 -04:00
cfg80211.h	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless	2012-03-27 22:15:01 -04:00
checksum.h
cipso_ipv4.h	doc: Update the email address for Paul Moore in various source files	2011-08-01 17:58:33 -07:00
cls_cgroup.h
compat.h	net: get rid of some pointless casts to sockaddr	2012-03-11 19:11:22 -07:00
datalink.h
dcbevent.h	dcb: Add stub routines for !CONFIG_DCB	2011-10-06 15:49:51 -04:00
dcbnl.h	net: dcb: getnumtcs()/setnumtcs() should return an int	2012-03-02 18:16:49 -08:00
dn_dev.h	decnet: RCU conversion and get rid of dev_base_lock	2010-11-08 13:50:08 -08:00
dn_fib.h	decnet: Convert to use flowidn where applicable.	2011-03-12 15:08:55 -08:00
dn_neigh.h
dn_nsp.h
dn_route.h	decnet: Convert to use flowidn where applicable.	2011-03-12 15:08:55 -08:00
dn.h	decnet: net/dn.h needs net/flow.h	2012-02-15 16:37:44 -05:00
dsa.h	dsa: Include linux/if_ether.h to fix build error	2011-12-01 11:41:06 -05:00
dsfield.h
dst_ops.h	net: Rename the dst_opt default_mtu method to mtu	2011-11-26 14:29:50 -05:00
dst.h	set fake_rtable's dst to NULL to avoid kernel Oops	2012-04-24 00:16:24 -04:00
esp.h
ethoc.h
fib_rules.h
flow_keys.h	flow_dissector: use a 64bit load/store	2011-11-29 13:17:03 -05:00
flow.h	ipv4: reset flowi parameters on route connect	2012-02-04 19:29:48 -05:00
garp.h	garp: remove last synchronize_rcu() call	2011-05-12 17:46:56 -04:00
gen_stats.h	Fix common misspellings	2011-03-31 11:26:23 -03:00
genetlink.h	net: Deinline __nlmsg_put and genlmsg_put. -7k code on i386 defconfig.	2012-01-30 15:22:06 -05:00
gre.h
icmp.h	ipv4: reduce percpu needs for icmpmsg mibs	2011-11-09 16:04:20 -05:00
ieee80211_radiotap.h	wireless: move ieee80211chan2mhz macro	2011-11-11 12:32:50 -05:00
ieee802154_netdev.h
ieee802154.h	6LoWPAN: add fragmentation support	2011-11-14 00:19:42 -05:00
if_inet6.h	ipv6: updates to privacy addresses per RFC 4941.	2011-08-01 18:05:00 -07:00
inet6_connection_sock.h	inet: Pass flowi to ->queue_xmit().	2011-05-08 15:28:28 -07:00
inet6_hashtables.h	net: use IS_ENABLED(CONFIG_IPV6)	2011-12-11 18:25:16 -05:00
inet_common.h
inet_connection_sock.h	net: rename sk_clone to sk_clone_lock	2011-11-08 17:07:07 -05:00
inet_ecn.h	inet: add rfc 3168 extract in front of INET_ECN_encapsulate()	2011-10-22 01:25:23 -04:00
inet_frag.h
inet_hashtables.h	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
inet_sock.h	net: implement IP_RECVTOS for IP_PKTOPTIONS	2012-02-13 00:46:41 -05:00
inet_timewait_sock.h	inet: remove rcu protection on tw_net	2011-12-14 13:34:55 -05:00
inetpeer.h	route: Remove redirect_genid	2012-03-08 00:30:32 -08:00
ip6_checksum.h
ip6_fib.h	ipv6: clean up rt6_clean_expires	2012-04-17 22:31:59 -04:00
ip6_route.h	Merge branch 'nf-next' of git://1984.lsi.us.es/net-next	2011-12-25 02:21:45 -05:00
ip6_tunnel.h
ip_fib.h	ipv4: Call fib_select_default() only when actually necessary.	2011-04-14 15:05:22 -07:00
ip_vs.h	ipvs: kernel oops - do_ip_vs_get_ctl	2012-04-30 10:40:35 +02:00
ip.h	ipv4: Make ip_call_ra_chain() return bool.	2012-03-09 14:34:50 -08:00
ipcomp.h
ipconfig.h
ipip.h
ipv6.h	ipv6: Add fragment reporting to ipv6_skip_exthdr().	2011-12-03 09:35:10 -08:00
ipx.h	net: Remove __KERNEL__ cpp checks from include/net	2011-04-24 10:54:56 -07:00
iw_handler.h	Fix common misspellings	2011-03-31 11:26:23 -03:00
lapb.h	wan: make LAPB callbacks const	2011-09-16 19:20:20 -04:00
lib80211.h	include: replace linux/module.h with "struct module" wherever possible	2011-10-31 19:32:32 -04:00
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h
llc_if.h
llc_pdu.h	bonding,llc: Fix structure sizeof incompatibility for some PDUs	2011-05-13 15:13:24 -04:00
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
llc.h	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
mac80211.h	mac80211: Convert WARN_ON to WARN_ON_ONCE	2012-04-09 15:54:48 -04:00
mip6.h
mld.h
ndisc.h	ipv6: Remove neigh argument from ndisc_send_redirect()	2012-01-27 21:00:08 -05:00
neighbour.h	ipv6: Use universal hash for NDISC.	2011-12-28 15:06:58 -05:00
net_namespace.h	net: use IS_ENABLED(CONFIG_IPV6)	2011-12-11 18:25:16 -05:00
net_ratelimit.h	net: Kill ratelimit.h dependency in linux/net.h	2011-05-27 13:41:33 -04:00
netdma.h
netevent.h	net: Remove __KERNEL__ cpp checks from include/net	2011-04-24 10:54:56 -07:00
netlabel.h	doc: Update the email address for Paul Moore in various source files	2011-08-01 17:58:33 -07:00
netlink.h	net: Deinline __nlmsg_put and genlmsg_put. -7k code on i386 defconfig.	2012-01-30 15:22:06 -05:00
netprio_cgroup.h	netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m	2012-02-10 15:08:57 -05:00
netrom.h
nexthop.h
nl802154.h
p8022.h
ping.h	net: ping: fix build failure	2011-05-17 14:16:58 -04:00
pkt_cls.h	net: Fix range checks in tcf_valid_offset().	2010-12-21 12:43:16 -08:00
pkt_sched.h	net: sched: constify tcf_proto and tc_action	2011-07-06 02:52:16 -07:00
protocol.h	net: use IS_ENABLED(CONFIG_IPV6)	2011-12-11 18:25:16 -05:00
psnap.h
raw.h
rawv6.h	net: Remove __KERNEL__ cpp checks from include/net	2011-04-24 10:54:56 -07:00
red.h	net_sched: red: Make minor corrections to comments	2012-04-16 23:53:11 -04:00
regulatory.h	cfg80211: pass DFS region to drivers through reg_notifier()	2011-11-21 16:20:41 -05:00
request_sock.h	tcp: Change possible SYN flooding messages	2011-09-15 14:49:43 -04:00
rose.h	rose: Add length checks to CALL_REQUEST parsing	2011-03-27 17:59:04 -07:00
route.h	ipv4: reset flowi parameters on route connect	2012-02-04 19:29:48 -05:00
rtnetlink.h	rtnetlink: Fix problem with buffer allocation	2012-02-21 16:56:45 -05:00
sch_generic.h	net: Make qdisc_skb_cb upper size bound explicit.	2012-02-09 13:50:34 -05:00
scm.h	af_unix: dont send SCM_CREDENTIALS by default	2011-09-28 13:29:50 -04:00
secure_seq.h	tcp: add const qualifiers where possible	2011-10-21 05:22:42 -04:00
slhc_vj.h
snmp.h	Merge branch 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2012-01-09 13:08:28 -08:00
sock.h	net: fix sk_sockets_allocated_read_positive	2012-04-30 13:37:59 -04:00
stp.h
tcp_memcontrol.h	cgroup: remove cgroup_subsys argument from callbacks	2012-02-02 09:20:22 -08:00
tcp_states.h
tcp.h	The following text was taken from the original review request:	2012-03-24 10:08:39 -07:00
timewait_sock.h	BUG: headers with BUG/BUG_ON etc. need linux/bug.h	2012-03-04 17:54:34 -05:00
transp_v6.h	net: relax PKTINFO non local ipv6 udp xmit check	2011-08-30 17:39:01 -04:00
udp.h	BUG: headers with BUG/BUG_ON etc. need linux/bug.h	2012-03-04 17:54:34 -05:00
udplite.h	net: ipv4: Standardize prefixes for message logging	2012-03-12 17:05:21 -07:00
wext.h
wimax.h	net: wimax: Remove of unused 'rfkill_input' pointer	2011-06-24 17:50:44 -07:00
wpan-phy.h	BUG: headers with BUG/BUG_ON etc. need linux/bug.h	2012-03-04 17:54:34 -05:00
x25.h	X25 remove bkl in subscription ioctls	2010-11-28 11:12:20 -08:00
x25device.h
xfrm.h	xfrm: remove unneeded method typedef declaration in net/xfrm.h.	2012-02-25 20:19:24 -05:00