GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-07-04 05:11:46 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

sched: Fix race in task_group()

Browse source 
Stefan reported a crash on a kernel before a3e5d1091c ("sched:
Don't call task_group() too many times in set_task_rq()"), he
found the reason to be that the multiple task_group()
invocations in set_task_rq() returned different values.

Looking at all that I found a lack of serialization and plain
wrong comments.

The below tries to fix it using an extra pointer which is
updated under the appropriate scheduler locks. Its not pretty,
but I can't really see another way given how all the cgroup
stuff works.

Reported-and-tested-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1340364965.18025.71.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2012-06-22 13:36:05 +02:00 • committed by Ingo Molnar
parent 88b8dac0a1
commit 8323f26ce3
4 changed files with 33 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

12
include/linux/init_task.h
View file

@ -123,8 +123,17 @@ extern struct group_info init_groups;
extern struct cred init_cred;
extern struct task_group root_task_group;
#ifdef CONFIG_CGROUP_SCHED
# define INIT_CGROUP_SCHED(tsk) \
.sched_task_group = &root_task_group,
#else
# define INIT_CGROUP_SCHED(tsk)
#endif
#ifdef CONFIG_PERF_EVENTS
# define INIT_PERF_EVENTS(tsk) \
# define INIT_PERF_EVENTS(tsk) \
.perf_event_mutex = \
__MUTEX_INITIALIZER(tsk.perf_event_mutex), \
.perf_event_list = LIST_HEAD_INIT(tsk.perf_event_list),
@ -161,6 +170,7 @@ extern struct cred init_cred;
}, \
.tasks = LIST_HEAD_INIT(tsk.tasks), \
INIT_PUSHABLE_TASKS(tsk) \
INIT_CGROUP_SCHED(tsk) \
.ptraced = LIST_HEAD_INIT(tsk.ptraced), \
.ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \
.real_parent = &tsk, \