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Eric Dumazet 144d56e910 tcp: fix possible socket refcount problem 
Commit 6f458dfb40 (tcp: improve latencies of timer triggered events)
added bug leading to following trace :

[ 2866.131281] IPv4: Attempt to release TCP socket in state 1 ffff880019ec0000
[ 2866.131726]
[ 2866.132188] =========================
[ 2866.132281] [ BUG: held lock freed! ]
[ 2866.132281] 3.6.0-rc1+ #622 Not tainted
[ 2866.132281] -------------------------
[ 2866.132281] kworker/0:1/652 is freeing memory ffff880019ec0000-ffff880019ec0a1f, with a lock still held there!
[ 2866.132281]  (sk_lock-AF_INET-RPC){+.+...}, at: [<ffffffff81903619>] tcp_sendmsg+0x29/0xcc6
[ 2866.132281] 4 locks held by kworker/0:1/652:
[ 2866.132281]  #0:  (rpciod){.+.+.+}, at: [<ffffffff81083567>] process_one_work+0x1de/0x47f
[ 2866.132281]  #1:  ((&task->u.tk_work)){+.+.+.}, at: [<ffffffff81083567>] process_one_work+0x1de/0x47f
[ 2866.132281]  #2:  (sk_lock-AF_INET-RPC){+.+...}, at: [<ffffffff81903619>] tcp_sendmsg+0x29/0xcc6
[ 2866.132281]  #3:  (&icsk->icsk_retransmit_timer){+.-...}, at: [<ffffffff81078017>] run_timer_softirq+0x1ad/0x35f
[ 2866.132281]
[ 2866.132281] stack backtrace:
[ 2866.132281] Pid: 652, comm: kworker/0:1 Not tainted 3.6.0-rc1+ #622
[ 2866.132281] Call Trace:
[ 2866.132281]  <IRQ>  [<ffffffff810bc527>] debug_check_no_locks_freed+0x112/0x159
[ 2866.132281]  [<ffffffff818a0839>] ? __sk_free+0xfd/0x114
[ 2866.132281]  [<ffffffff811549fa>] kmem_cache_free+0x6b/0x13a
[ 2866.132281]  [<ffffffff818a0839>] __sk_free+0xfd/0x114
[ 2866.132281]  [<ffffffff818a08c0>] sk_free+0x1c/0x1e
[ 2866.132281]  [<ffffffff81911e1c>] tcp_write_timer+0x51/0x56
[ 2866.132281]  [<ffffffff81078082>] run_timer_softirq+0x218/0x35f
[ 2866.132281]  [<ffffffff81078017>] ? run_timer_softirq+0x1ad/0x35f
[ 2866.132281]  [<ffffffff810f5831>] ? rb_commit+0x58/0x85
[ 2866.132281]  [<ffffffff81911dcb>] ? tcp_write_timer_handler+0x148/0x148
[ 2866.132281]  [<ffffffff81070bd6>] __do_softirq+0xcb/0x1f9
[ 2866.132281]  [<ffffffff81a0a00c>] ? _raw_spin_unlock+0x29/0x2e
[ 2866.132281]  [<ffffffff81a1227c>] call_softirq+0x1c/0x30
[ 2866.132281]  [<ffffffff81039f38>] do_softirq+0x4a/0xa6
[ 2866.132281]  [<ffffffff81070f2b>] irq_exit+0x51/0xad
[ 2866.132281]  [<ffffffff81a129cd>] do_IRQ+0x9d/0xb4
[ 2866.132281]  [<ffffffff81a0a3ef>] common_interrupt+0x6f/0x6f
[ 2866.132281]  <EOI>  [<ffffffff8109d006>] ? sched_clock_cpu+0x58/0xd1
[ 2866.132281]  [<ffffffff81a0a172>] ? _raw_spin_unlock_irqrestore+0x4c/0x56
[ 2866.132281]  [<ffffffff81078692>] mod_timer+0x178/0x1a9
[ 2866.132281]  [<ffffffff818a00aa>] sk_reset_timer+0x19/0x26
[ 2866.132281]  [<ffffffff8190b2cc>] tcp_rearm_rto+0x99/0xa4
[ 2866.132281]  [<ffffffff8190dfba>] tcp_event_new_data_sent+0x6e/0x70
[ 2866.132281]  [<ffffffff8190f7ea>] tcp_write_xmit+0x7de/0x8e4
[ 2866.132281]  [<ffffffff818a565d>] ? __alloc_skb+0xa0/0x1a1
[ 2866.132281]  [<ffffffff8190f952>] __tcp_push_pending_frames+0x2e/0x8a
[ 2866.132281]  [<ffffffff81904122>] tcp_sendmsg+0xb32/0xcc6
[ 2866.132281]  [<ffffffff819229c2>] inet_sendmsg+0xaa/0xd5
[ 2866.132281]  [<ffffffff81922918>] ? inet_autobind+0x5f/0x5f
[ 2866.132281]  [<ffffffff810ee7f1>] ? trace_clock_local+0x9/0xb
[ 2866.132281]  [<ffffffff8189adab>] sock_sendmsg+0xa3/0xc4
[ 2866.132281]  [<ffffffff810f5de6>] ? rb_reserve_next_event+0x26f/0x2d5
[ 2866.132281]  [<ffffffff8103e6a9>] ? native_sched_clock+0x29/0x6f
[ 2866.132281]  [<ffffffff8103e6f8>] ? sched_clock+0x9/0xd
[ 2866.132281]  [<ffffffff810ee7f1>] ? trace_clock_local+0x9/0xb
[ 2866.132281]  [<ffffffff8189ae03>] kernel_sendmsg+0x37/0x43
[ 2866.132281]  [<ffffffff8199ce49>] xs_send_kvec+0x77/0x80
[ 2866.132281]  [<ffffffff8199cec1>] xs_sendpages+0x6f/0x1a0
[ 2866.132281]  [<ffffffff8107826d>] ? try_to_del_timer_sync+0x55/0x61
[ 2866.132281]  [<ffffffff8199d0d2>] xs_tcp_send_request+0x55/0xf1
[ 2866.132281]  [<ffffffff8199bb90>] xprt_transmit+0x89/0x1db
[ 2866.132281]  [<ffffffff81999bcd>] ? call_connect+0x3c/0x3c
[ 2866.132281]  [<ffffffff81999d92>] call_transmit+0x1c5/0x20e
[ 2866.132281]  [<ffffffff819a0d55>] __rpc_execute+0x6f/0x225
[ 2866.132281]  [<ffffffff81999bcd>] ? call_connect+0x3c/0x3c
[ 2866.132281]  [<ffffffff819a0f33>] rpc_async_schedule+0x28/0x34
[ 2866.132281]  [<ffffffff810835d6>] process_one_work+0x24d/0x47f
[ 2866.132281]  [<ffffffff81083567>] ? process_one_work+0x1de/0x47f
[ 2866.132281]  [<ffffffff819a0f0b>] ? __rpc_execute+0x225/0x225
[ 2866.132281]  [<ffffffff81083a6d>] worker_thread+0x236/0x317
[ 2866.132281]  [<ffffffff81083837>] ? process_scheduled_works+0x2f/0x2f
[ 2866.132281]  [<ffffffff8108b7b8>] kthread+0x9a/0xa2
[ 2866.132281]  [<ffffffff81a12184>] kernel_thread_helper+0x4/0x10
[ 2866.132281]  [<ffffffff81a0a4b0>] ? retint_restore_args+0x13/0x13
[ 2866.132281]  [<ffffffff8108b71e>] ? __init_kthread_worker+0x5a/0x5a
[ 2866.132281]  [<ffffffff81a12180>] ? gs_change+0x13/0x13
[ 2866.308506] IPv4: Attempt to release TCP socket in state 1 ffff880019ec0000
[ 2866.309689] =============================================================================
[ 2866.310254] BUG TCP (Not tainted): Object already free
[ 2866.310254] -----------------------------------------------------------------------------
[ 2866.310254]

The bug comes from the fact that timer set in sk_reset_timer() can run
before we actually do the sock_hold(). socket refcount reaches zero and
we free the socket too soon.

timer handler is not allowed to reduce socket refcnt if socket is owned
by the user, or we need to change sk_reset_timer() implementation.

We should take a reference on the socket in case TCP_DELACK_TIMER_DEFERRED
or TCP_DELACK_TIMER_DEFERRED bit are set in tsq_flags

Also fix a typo in tcp_delack_timer(), where TCP_WRITE_TIMER_DEFERRED
was used instead of TCP_DELACK_TIMER_DEFERRED.

For consistency, use same socket refcount change for TCP_MTU_REDUCED_DEFERRED,
even if not fired from a timer.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-21 14:42:23 -07:00
..
9p net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
802 tokenring: delete all remaining driver support 2012-05-15 20:23:16 -04:00
8021q vlan: clean up vlan_dev_hard_start_xmit() 2012-08-14 14:33:32 -07:00
appletalk net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
atm atm: fix info leak via getsockname() 2012-08-15 21:36:30 -07:00
ax25 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-07-19 11:17:30 -07:00
batman-adv batman-adv: Fix mem leak in the batadv_tt_local_event() function 2012-08-08 16:04:04 -07:00
bluetooth Bluetooth: L2CAP - Fix info leak via getsockname() 2012-08-15 21:36:31 -07:00
bridge bridge: fix rcu dereference outside of rcu_read_lock 2012-08-15 15:09:41 -07:00
caif caif: Do not dereference NULL in chnl_recv_cb() 2012-08-20 02:47:49 -07:00
can can: gw: Remove pointless casts 2012-07-10 22:36:17 +02:00
ceph libceph: fix crypto key null deref, memory leak 2012-08-02 09:19:20 -07:00
core net/core/dev.c: fix kernel-doc warning 2012-08-20 03:00:55 -07:00
dcb net: Fix non-kernel-doc comments with kernel-doc start marker 2012-07-10 23:13:45 -07:00
dccp dccp: fix info leak via getsockopt(DCCP_SOCKOPT_CCID_TX_INFO) 2012-08-15 21:36:31 -07:00
decnet ipv4: Restore old dst_free() behavior. 2012-07-31 14:41:38 -07:00
dns_resolver Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2012-05-21 20:27:36 -07:00
dsa dsa: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:19 -04:00
ethernet ipx: move peII functions 2012-07-19 10:48:00 -07:00
ieee802154 6lowpan: Change byte order when storing/accessing to len field 2012-07-16 22:52:02 -07:00
ipv4 tcp: fix possible socket refcount problem 2012-08-21 14:42:23 -07:00
ipv6 net: tcp: move sk_rx_dst_set call after tcp_create_openreq_child() 2012-08-20 03:03:33 -07:00
ipx ipx: move peII functions 2012-07-19 10:48:00 -07:00
irda irda: Fix typo in irda 2012-07-16 23:23:52 -07:00
iucv net: remove skb_orphan_try() 2012-06-15 15:30:15 -07:00
key net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
l2tp l2tp: fix info leak via getsockname() 2012-08-15 21:36:31 -07:00
lapb lapb: Neaten debugging 2012-05-17 18:45:20 -04:00
llc llc: fix info leak via getsockname() 2012-08-15 21:36:31 -07:00
mac80211 Merge branch 'for-john' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211 2012-08-02 13:49:38 -04:00
mac802154 mac802154: sparse warnings: make symbols static 2012-07-12 07:54:45 -07:00
netfilter Merge git://1984.lsi.us.es/nf 2012-08-20 02:44:29 -07:00
netlabel
netlink genetlink: define lockdep_genl_is_held() when CONFIG_LOCKDEP 2012-07-24 00:01:30 -07:00
netrom net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
nfc Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem 2012-07-20 12:30:48 -04:00
openvswitch Revert "openvswitch: potential NULL deref in sample()" 2012-07-27 13:45:51 -07:00
packet af_packet: don't emit packet on orig fanout group 2012-08-20 02:37:29 -07:00
phonet net: remove my future former mail address 2012-06-17 16:29:38 -07:00
rds rds: set correct msg_namelen 2012-07-23 01:01:44 -07:00
rfkill rfkill: Add the capability to switch all devices of all type in __rfkill_switch_all(). 2012-06-06 15:18:17 -04:00
rose net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
rxrpc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-07-10 23:56:33 -07:00
sched act_mirred: do not drop packets when fails to mirror it 2012-08-16 14:54:44 -07:00
sctp netvm: prevent a stream-specific deadlock 2012-07-31 18:42:47 -07:00
sunrpc Merge branch 'akpm' (Andrew's patch-bomb) 2012-07-31 19:25:39 -07:00
tipc tipc: remove print_buf and deprecated log buffer code 2012-07-13 19:34:43 -04:00
unix Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-08-01 10:26:23 -07:00
wanrouter wanmain: comparing array with NULL 2012-07-24 13:55:21 -07:00
wimax net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
wireless cfg80211: process pending events when unregistering net device 2012-08-06 14:29:58 -04:00
x25 net: Fix (nearly-)kernel-doc comments for various functions 2012-07-10 23:13:45 -07:00
xfrm net: ipv6: fix oops in inet_putpeer() 2012-08-20 02:56:56 -07:00
compat.c net: Fix references to out-of-scope variables in put_cmsg_compat() 2012-07-22 17:50:49 -07:00
Kconfig net: drop NET dependency from HAVE_BPF_JIT 2012-05-21 12:50:12 -07:00
Makefile econet: remove ancient bug ridden protocol 2012-05-18 01:35:08 -04:00
nonet.c
socket.c net: fix info leak in compat dev_ifconf() 2012-08-15 21:36:31 -07:00
sysctl_net.c net: delete all instances of special processing for token ring 2012-05-15 20:14:35 -04:00