linux

iv/linux

History

Tejun Heo 14611e51a5 cgroup: fix RCU accesses to task->cgroups

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>
Cc: stable@vger.kernel.org

2013-06-26 10:42:46 -07:00

acpi

ACPI / PM: Allow device power states to be used for CONFIG_PM unset

2013-05-22 00:19:28 +02:00

asm-generic

kernel: Fix s390 absolute memory access for /dev/mem

2013-05-22 09:45:57 +02:00

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