Pavel Emelyanov 0fa7fa98db packet: Protect packet sk list with mutex (v2) ... Change since v1: * Fixed inuse counters access spotted by Eric In patch eea68e2f (packet: Report socket mclist info via diag module) I've introduced a "scheduling in atomic" problem in packet diag module -- the socket list is traversed under rcu_read_lock() while performed under it sk mclist access requires rtnl lock (i.e. -- mutex) to be taken. [152363.820563] BUG: scheduling while atomic: crtools/12517/0x10000002 [152363.820573] 4 locks held by crtools/12517: [152363.820581] #0: (sock_diag_mutex){+.+.+.}, at: [<ffffffff81a2dcb5>] sock_diag_rcv+0x1f/0x3e [152363.820613] #1: (sock_diag_table_mutex){+.+.+.}, at: [<ffffffff81a2de70>] sock_diag_rcv_msg+0xdb/0x11a [152363.820644] #2: (nlk->cb_mutex){+.+.+.}, at: [<ffffffff81a67d01>] netlink_dump+0x23/0x1ab [152363.820693] #3: (rcu_read_lock){.+.+..}, at: [<ffffffff81b6a049>] packet_diag_dump+0x0/0x1af Similar thing was then re-introduced by further packet diag patches (fanount mutex and pgvec mutex for rings) :( Apart from being terribly sorry for the above, I propose to change the packet sk list protection from spinlock to mutex. This lock currently protects two modifications: * sklist * prot inuse counters The sklist modifications can be just reprotected with mutex since they already occur in a sleeping context. The inuse counters modifications are trickier -- the __this_cpu_-s are used inside, thus requiring the caller to handle the potential issues with contexts himself. Since packet sockets' counters are modified in two places only (packet_create and packet_release) we only need to protect the context from being preempted. BH disabling is not required in this case. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2012-08-22 22:58:27 -07:00
..
conntrack.h	netfilter: nf_ct_icmp: add namespace support	2012-06-07 14:58:40 +02:00
core.h	percpu: add __percpu sparse annotations to net	2010-02-16 23:05:38 -08:00
dccp.h	[NETNS][DCCPV6]: Move the dccp_v6_ctl_sk on the struct net.	2008-04-13 22:32:25 -07:00
generic.h	BUG: headers with BUG/BUG_ON etc. need linux/bug.h	2012-03-04 17:54:34 -05:00
hash.h	net: cleanup unsigned to unsigned int	2012-04-15 12:44:40 -04:00
ipv4.h	ipv4: remove rt_cache_rebuild_count	2012-07-30 14:53:22 -07:00
ipv6.h	inetpeer: add namespace support for inetpeer	2012-06-08 14:27:23 -07:00
mib.h	net: use IS_ENABLED(CONFIG_IPV6)	2011-12-11 18:25:16 -05:00
packet.h	packet: Protect packet sk list with mutex (v2)	2012-08-22 22:58:27 -07:00
sctp.h	sctp: Make sysctl tunables per net	2012-08-14 23:32:16 -07:00
unix.h
x_tables.h	net, netns_xt: shrink netns_xt members	2009-07-05 19:16:18 -07:00
xfrm.h	net: use IS_ENABLED(CONFIG_IPV6)	2011-12-11 18:25:16 -05:00