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authorJann Horn <jannh@google.com>2019-07-16 17:20:47 +0200
committerIngo Molnar <mingo@kernel.org>2019-07-25 15:37:05 +0200
commitcb361d8cdef69990f6b4504dc1fd9a594d983c97 (patch)
treecde527557b6259487a11df5f30a652ab965cda41 /include
parent16d51a590a8ce3befb1308e0e7ab77f3b661af33 (diff)
sched/fair: Use RCU accessors consistently for ->numa_group
The old code used RCU annotations and accessors inconsistently for ->numa_group, which can lead to use-after-frees and NULL dereferences. Let all accesses to ->numa_group use proper RCU helpers to prevent such issues. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Fixes: 8c8a743c5087 ("sched/numa: Use {cpu, pid} to create task groups for shared faults") Link: https://lkml.kernel.org/r/20190716152047.14424-3-jannh@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/sched.h10
1 files changed, 9 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8dc1811487f5..9f51932bd543 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1092,7 +1092,15 @@ struct task_struct {
u64 last_sum_exec_runtime;
struct callback_head numa_work;
- struct numa_group *numa_group;
+ /*
+ * This pointer is only modified for current in syscall and
+ * pagefault context (and for tasks being destroyed), so it can be read
+ * from any of the following contexts:
+ * - RCU read-side critical section
+ * - current->numa_group from everywhere
+ * - task's runqueue locked, task not running
+ */
+ struct numa_group __rcu *numa_group;
/*
* numa_faults is an array split into four regions: