Revision b1dd693e5b9348bd68a80e679e03cf9c0973b01b authored by Daisuke Nishimura on 24 November 2010, 20:57:06 UTC, committed by Linus Torvalds on 24 November 2010, 21:50:44 UTC
__mem_cgroup_try_charge() can be called under down_write(&mmap_sem)(e.g. mlock does it). This means it can cause deadlock if it races with move charge: Ex.1) move charge | try charge --------------------------------------+------------------------------ mem_cgroup_can_attach() | down_write(&mmap_sem) mc.moving_task = current | .. mem_cgroup_precharge_mc() | __mem_cgroup_try_charge() mem_cgroup_count_precharge() | prepare_to_wait() down_read(&mmap_sem) | if (mc.moving_task) -> cannot aquire the lock | -> true | schedule() Ex.2) move charge | try charge --------------------------------------+------------------------------ mem_cgroup_can_attach() | mc.moving_task = current | mem_cgroup_precharge_mc() | mem_cgroup_count_precharge() | down_read(&mmap_sem) | .. | up_read(&mmap_sem) | | down_write(&mmap_sem) mem_cgroup_move_task() | .. mem_cgroup_move_charge() | __mem_cgroup_try_charge() down_read(&mmap_sem) | prepare_to_wait() -> cannot aquire the lock | if (mc.moving_task) | -> true | schedule() To avoid this deadlock, we do all the move charge works (both can_attach() and attach()) under one mmap_sem section. And after this patch, we set/clear mc.moving_task outside mc.lock, because we use the lock only to check mc.from/to. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Makefile
#
# Makefile for the linux networking.
#
# 2 Sep 2000, Christoph Hellwig <hch@infradead.org>
# Rewritten to use lists instead of if-statements.
#
obj-y := nonet.o
obj-$(CONFIG_NET) := socket.o core/
tmp-$(CONFIG_COMPAT) := compat.o
obj-$(CONFIG_NET) += $(tmp-y)
# LLC has to be linked before the files in net/802/
obj-$(CONFIG_LLC) += llc/
obj-$(CONFIG_NET) += ethernet/ 802/ sched/ netlink/
obj-$(CONFIG_NETFILTER) += netfilter/
obj-$(CONFIG_INET) += ipv4/
obj-$(CONFIG_XFRM) += xfrm/
obj-$(CONFIG_UNIX) += unix/
ifneq ($(CONFIG_IPV6),)
obj-y += ipv6/
endif
obj-$(CONFIG_PACKET) += packet/
obj-$(CONFIG_NET_KEY) += key/
obj-$(CONFIG_BRIDGE) += bridge/
obj-$(CONFIG_NET_DSA) += dsa/
obj-$(CONFIG_IPX) += ipx/
obj-$(CONFIG_ATALK) += appletalk/
obj-$(CONFIG_WAN_ROUTER) += wanrouter/
obj-$(CONFIG_X25) += x25/
obj-$(CONFIG_LAPB) += lapb/
obj-$(CONFIG_NETROM) += netrom/
obj-$(CONFIG_ROSE) += rose/
obj-$(CONFIG_AX25) += ax25/
obj-$(CONFIG_CAN) += can/
obj-$(CONFIG_IRDA) += irda/
obj-$(CONFIG_BT) += bluetooth/
obj-$(CONFIG_SUNRPC) += sunrpc/
obj-$(CONFIG_AF_RXRPC) += rxrpc/
obj-$(CONFIG_ATM) += atm/
obj-$(CONFIG_L2TP) += l2tp/
obj-$(CONFIG_DECNET) += decnet/
obj-$(CONFIG_ECONET) += econet/
obj-$(CONFIG_PHONET) += phonet/
ifneq ($(CONFIG_VLAN_8021Q),)
obj-y += 8021q/
endif
obj-$(CONFIG_IP_DCCP) += dccp/
obj-$(CONFIG_IP_SCTP) += sctp/
obj-$(CONFIG_RDS) += rds/
obj-$(CONFIG_WIRELESS) += wireless/
obj-$(CONFIG_MAC80211) += mac80211/
obj-$(CONFIG_TIPC) += tipc/
obj-$(CONFIG_NETLABEL) += netlabel/
obj-$(CONFIG_IUCV) += iucv/
obj-$(CONFIG_RFKILL) += rfkill/
obj-$(CONFIG_NET_9P) += 9p/
obj-$(CONFIG_CAIF) += caif/
ifneq ($(CONFIG_DCB),)
obj-y += dcb/
endif
obj-$(CONFIG_IEEE802154) += ieee802154/
ifeq ($(CONFIG_NET),y)
obj-$(CONFIG_SYSCTL) += sysctl_net.o
endif
obj-$(CONFIG_WIMAX) += wimax/
obj-$(CONFIG_DNS_RESOLVER) += dns_resolver/
obj-$(CONFIG_CEPH_LIB) += ceph/
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