The following commit has been merged into the sched/urgent branch of tip:
Commit-ID: 8e5bad7dccec2014f24497b57d8a8ee0b752c290
Gitweb: https://git.kernel.org/tip/8e5bad7dccec2014f24497b57d8a8ee0b752c290
Author: Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate: Fri, 07 Oct 2022 17:07:58 -07:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 17 Oct 2022 16:41:25 +02:00
sched: Introduce struct balance_callback to avoid CFI mismatches
Introduce distinct struct balance_callback instead of performing function
pointer casting which will trip CFI. Avoids warnings as found by Clang's
future -Wcast-function-type-strict option:
In file included from kernel/sched/core.c:84:
kernel/sched/sched.h:1755:15: warning: cast from 'void (*)(struct rq *)' to 'void (*)(struct callback_head *)' converts to incompatible function type [-Wcast-function-type-strict]
head->func = (void (*)(struct callback_head *))func;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
No binary differences result from this change.
This patch is a cleanup based on Brad Spengler/PaX Team's modifications
to sched code in their last public patch of grsecurity/PaX based on my
understanding of the code. Changes or omissions from the original code
are mine and don't reflect the original grsecurity/PaX code.
Reported-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Link: https://github.com/ClangBuiltLinux/linux/issues/1724
Link: https://lkml.kernel.org/r/20221008000758.2957718-1-keescook@xxxxxxxxxxxx
---
kernel/sched/core.c | 24 ++++++++++++------------
kernel/sched/deadline.c | 4 ++--
kernel/sched/rt.c | 4 ++--
kernel/sched/sched.h | 14 ++++++++++----
4 files changed, 26 insertions(+), 20 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5800b06..cb2aa2b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4823,10 +4823,10 @@ static inline void finish_task(struct task_struct *prev)
#ifdef CONFIG_SMP
-static void do_balance_callbacks(struct rq *rq, struct callback_head *head)
+static void do_balance_callbacks(struct rq *rq, struct balance_callback *head)
{
void (*func)(struct rq *rq);
- struct callback_head *next;
+ struct balance_callback *next;
lockdep_assert_rq_held(rq);
@@ -4853,15 +4853,15 @@ static void balance_push(struct rq *rq);
* This abuse is tolerated because it places all the unlikely/odd cases behind
* a single test, namely: rq->balance_callback == NULL.
*/
-struct callback_head balance_push_callback = {
+struct balance_callback balance_push_callback = {
.next = NULL,
- .func = (void (*)(struct callback_head *))balance_push,
+ .func = balance_push,
};
-static inline struct callback_head *
+static inline struct balance_callback *
__splice_balance_callbacks(struct rq *rq, bool split)
{
- struct callback_head *head = rq->balance_callback;
+ struct balance_callback *head = rq->balance_callback;
if (likely(!head))
return NULL;
@@ -4883,7 +4883,7 @@ __splice_balance_callbacks(struct rq *rq, bool split)
return head;
}
-static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
+static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
{
return __splice_balance_callbacks(rq, true);
}
@@ -4893,7 +4893,7 @@ static void __balance_callbacks(struct rq *rq)
do_balance_callbacks(rq, __splice_balance_callbacks(rq, false));
}
-static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
+static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
{
unsigned long flags;
@@ -4910,12 +4910,12 @@ static inline void __balance_callbacks(struct rq *rq)
{
}
-static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
+static inline struct balance_callback *splice_balance_callbacks(struct rq *rq)
{
return NULL;
}
-static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
+static inline void balance_callbacks(struct rq *rq, struct balance_callback *head)
{
}
@@ -6188,7 +6188,7 @@ static void sched_core_balance(struct rq *rq)
preempt_enable();
}
-static DEFINE_PER_CPU(struct callback_head, core_balance_head);
+static DEFINE_PER_CPU(struct balance_callback, core_balance_head);
static void queue_core_balance(struct rq *rq)
{
@@ -7419,7 +7419,7 @@ static int __sched_setscheduler(struct task_struct *p,
int oldpolicy = -1, policy = attr->sched_policy;
int retval, oldprio, newprio, queued, running;
const struct sched_class *prev_class;
- struct callback_head *head;
+ struct balance_callback *head;
struct rq_flags rf;
int reset_on_fork;
int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 86dea6a..9ae8f41 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -644,8 +644,8 @@ static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
return rq->online && dl_task(prev);
}
-static DEFINE_PER_CPU(struct callback_head, dl_push_head);
-static DEFINE_PER_CPU(struct callback_head, dl_pull_head);
+static DEFINE_PER_CPU(struct balance_callback, dl_push_head);
+static DEFINE_PER_CPU(struct balance_callback, dl_pull_head);
static void push_dl_tasks(struct rq *);
static void pull_dl_task(struct rq *);
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index d869bcf..ed2a47e 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -410,8 +410,8 @@ static inline int has_pushable_tasks(struct rq *rq)
return !plist_head_empty(&rq->rt.pushable_tasks);
}
-static DEFINE_PER_CPU(struct callback_head, rt_push_head);
-static DEFINE_PER_CPU(struct callback_head, rt_pull_head);
+static DEFINE_PER_CPU(struct balance_callback, rt_push_head);
+static DEFINE_PER_CPU(struct balance_callback, rt_pull_head);
static void push_rt_tasks(struct rq *);
static void pull_rt_task(struct rq *);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 0d08511..a4a2004 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -938,6 +938,12 @@ struct uclamp_rq {
DECLARE_STATIC_KEY_FALSE(sched_uclamp_used);
#endif /* CONFIG_UCLAMP_TASK */
+struct rq;
+struct balance_callback {
+ struct balance_callback *next;
+ void (*func)(struct rq *rq);
+};
+
/*
* This is the main, per-CPU runqueue data structure.
*
@@ -1036,7 +1042,7 @@ struct rq {
unsigned long cpu_capacity;
unsigned long cpu_capacity_orig;
- struct callback_head *balance_callback;
+ struct balance_callback *balance_callback;
unsigned char nohz_idle_balance;
unsigned char idle_balance;
@@ -1544,7 +1550,7 @@ struct rq_flags {
#endif
};
-extern struct callback_head balance_push_callback;
+extern struct balance_callback balance_push_callback;
/*
* Lockdep annotation that avoids accidental unlocks; it's like a
@@ -1724,7 +1730,7 @@ init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
static inline void
queue_balance_callback(struct rq *rq,
- struct callback_head *head,
+ struct balance_callback *head,
void (*func)(struct rq *rq))
{
lockdep_assert_rq_held(rq);
@@ -1737,7 +1743,7 @@ queue_balance_callback(struct rq *rq,
if (unlikely(head->next || rq->balance_callback == &balance_push_callback))
return;
- head->func = (void (*)(struct callback_head *))func;
+ head->func = func;
head->next = rq->balance_callback;
rq->balance_callback = head;
}
|