Tejun Heo b6891ed4e6 cgroup: fix RCU accesses to task->cgroups ... commit 14611e51a5 upstream. task->cgroups is a RCU pointer pointing to struct css_set. A task switches to a different css_set on cgroup migration but a css_set doesn't change once created and its pointers to cgroup_subsys_states aren't RCU protected. task_subsys_state[_check]() is the macro to acquire css given a task and subsys_id pair. It RCU-dereferences task->cgroups->subsys[] not task->cgroups, so the RCU pointer task->cgroups ends up being dereferenced without read_barrier_depends() after it. It's broken. Fix it by introducing task_css_set[_check]() which does RCU-dereference on task->cgroups. task_subsys_state[_check]() is reimplemented to directly dereference ->subsys[] of the css_set returned from task_css_set[_check](). This removes some of sparse RCU warnings in cgroup. v2: Fixed unbalanced parenthsis and there's no need to use rcu_dereference_raw() when !CONFIG_PROVE_RCU. Both spotted by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2013-07-21 18:21:25 -07:00
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acpi	ACPI / dock / PCI: Synchronous handling of dock events for PCI devices	2013-06-24 11:22:53 +02:00
asm-generic	Merge branch 'fixes' of git://git.kernel.org/pub/scm/virt/kvm/kvm	2013-06-11 11:16:43 -07:00
clocksource	ARM: late Exynos multiplatform changes	2013-05-07 11:28:42 -07:00
crypto	crypto: sha512 - Expose generic sha512 routine to be callable from other modules	2013-04-25 21:00:57 +08:00
drm	Merge branch 'drm-radeon-sun-hainan' of git://people.freedesktop.org/~airlied/linux	2013-05-21 08:50:57 -07:00
dt-bindings
keys
linux	cgroup: fix RCU accesses to task->cgroups	2013-07-21 18:21:25 -07:00
math-emu
media	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2013-06-18 06:25:08 -10:00
memory
misc
net	ip_tunnel: remove __net_init/exit from exported functions	2013-06-13 03:00:59 -07:00
pcmcia
ras
rdma
rxrpc
scsi	Merge branch 'postmerge' into for-linus	2013-05-10 07:54:01 -07:00
sound	ASoC: dapm: Treat DAI widgets like AIF widgets for power	2013-06-07 15:54:50 +01:00
target	target: Propigate up ->cmd_kref put return via transport_generic_free_cmd	2013-05-31 01:21:23 -07:00
trace	Fixed regressions (two stability regressions and a performance	2013-05-14 09:30:54 -07:00
uapi	netlink: export netlink_diag.h header	2013-06-19 18:30:27 -07:00
video	Merge branch 'fbdev-3.10-fixes' of git://gitorious.org/linux-omap-dss2/linux into linux-fbdev/for-3.10-fixes	2013-05-29 17:00:34 +08:00
xen	xenbus: delay xenbus frontend resume if xenstored is not running	2013-05-29 09:04:19 -04:00
Kbuild	UAPI: remove empty Kbuild files	2013-04-30 17:04:09 -07:00