linux/net
Dmitry Mishin 7c91767a6b [NET]: add_timer -> mod_timer() in dst_run_gc()
Patch from Dmitry Mishin <dim@openvz.org>:

Replace add_timer() by mod_timer() in dst_run_gc
in order to avoid BUG message.

       CPU1                            CPU2
dst_run_gc()  entered           dst_run_gc() entered
spin_lock(&dst_lock)                   .....
del_timer(&dst_gc_timer)         fail to get lock
       ....                         mod_timer() <--- puts 
                                                 timer back
                                                 to the list
add_timer(&dst_gc_timer) <--- BUG because timer is in list already.

Found during OpenVZ internal testing.

At first we thought that it is OpenVZ specific as we
added dst_run_gc(0) call in dst_dev_event(),
but as Alexey pointed to me it is possible to trigger
this condition in mainstream kernel.

F.e. timer has fired on CPU2, but the handler was preeempted
by an irq before dst_lock is tried.
Meanwhile, someone on CPU1 adds an entry to gc list and
starts the timer.
If CPU2 was preempted long enough, this timer can expire
simultaneously with resuming timer handler on CPU1, arriving
exactly to the situation described.

Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-09 02:25:54 -07:00
..
802 Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
8021q [VLAN]: Fix link state propagation 2006-07-24 13:52:13 -07:00
appletalk [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
atm [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
ax25 [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
bluetooth [Bluetooth] Correct RFCOMM channel MTU for broken implementations 2006-07-24 12:44:25 -07:00
bridge [BRIDGE]: netlink status fix 2006-08-04 22:59:48 -07:00
core [NET]: add_timer -> mod_timer() in dst_run_gc() 2006-08-09 02:25:54 -07:00
dccp [IPV6]: Audit all ip6_dst_lookup/ip6_dst_store calls 2006-08-02 13:38:14 -07:00
decnet [DECNET]: Fix for routing bug 2006-08-02 14:14:44 -07:00
econet [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
ethernet Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
ieee80211 [PATCH] ieee80211: TKIP requires CRC32 2006-07-27 14:37:31 -04:00
ipv4 [TCP]: SNMPv2 tcpOutSegs counter error 2006-08-07 21:04:15 -07:00
ipv6 [IPV6]: SNMPv2 "ipv6IfStatsOutFragCreates" counter error 2006-08-02 13:41:21 -07:00
ipx [IPX]: Another nonlinear receive fix 2006-08-08 16:48:51 -07:00
irda [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
key Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
lapb [LAPB]: Fix windowsize check 2006-08-05 21:15:58 -07:00
llc [LLX]: SOCK_DGRAM interface fixes 2006-08-04 22:59:50 -07:00
netfilter [NETFILTER]: xt_hashlimit/xt_string: missing string validation 2006-08-02 13:38:29 -07:00
netlink [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
netrom [NETROM] lockdep: fix false positive 2006-07-12 13:59:02 -07:00
packet Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
rose [ROSE] lockdep: fix false positive 2006-07-12 13:58:59 -07:00
rxrpc [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
sched [PKT_SCHED]: Return ENOENT if qdisc module is unavailable 2006-08-04 22:59:49 -07:00
sctp [SCTP]: ADDIP: Don't use an address as source until it is ASCONF-ACKed 2006-07-21 14:49:25 -07:00
sunrpc [PATCH] knfsd: fix race related problem when adding items to and svcrpc auth cache 2006-08-06 08:57:47 -07:00
tipc [TIPC]: Removing useless casts 2006-07-21 15:52:20 -07:00
unix [AF_UNIX]: Kernel memory leak fix for af_unix datagram getpeersec patch 2006-08-02 14:12:06 -07:00
wanrouter [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
x25 Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
xfrm [NET]: Conversions from kmalloc+memset to k(z|c)alloc. 2006-07-21 14:51:30 -07:00
compat.c [NETFILTER]: iptables 32bit compat layer 2006-04-01 02:25:19 -08:00
Kconfig [SECMARK]: Add secmark support to core networking. 2006-06-17 21:29:57 -07:00
Makefile [TIPC] Initial merge 2006-01-12 14:06:31 -08:00
nonet.c [PATCH] Make most file operations structs in fs/ const 2006-03-28 09:16:06 -08:00
socket.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
sysctl_net.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
TUNABLE Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00