Message ID | 20221008000758.2957718-1-keescook@chromium.org (mailing list archive) |
---|---|
State | Mainlined |
Commit | 8e5bad7dccec2014f24497b57d8a8ee0b752c290 |
Headers | show |
Series | sched: Introduce struct balance_callback to avoid CFI mismatches | expand |
On Fri, Oct 07, 2022 at 05:07:58PM -0700, Kees Cook wrote: > 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@google.com> > Link: https://github.com/ClangBuiltLinux/linux/issues/1724 > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Juri Lelli <juri.lelli@redhat.com> > Cc: Vincent Guittot <vincent.guittot@linaro.org> > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Ben Segall <bsegall@google.com> > Cc: Mel Gorman <mgorman@suse.de> > Cc: Daniel Bristot de Oliveira <bristot@redhat.com> > Cc: Valentin Schneider <vschneid@redhat.com> > Cc: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > 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(-) Thanks!
On Fri, Oct 07, 2022 at 05:07:58PM -0700, Kees Cook wrote: > 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@google.com> > Link: https://github.com/ClangBuiltLinux/linux/issues/1724 > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Juri Lelli <juri.lelli@redhat.com> > Cc: Vincent Guittot <vincent.guittot@linaro.org> > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Ben Segall <bsegall@google.com> > Cc: Mel Gorman <mgorman@suse.de> > Cc: Daniel Bristot de Oliveira <bristot@redhat.com> > Cc: Valentin Schneider <vschneid@redhat.com> > Cc: Gustavo A. R. Silva <gustavoars@kernel.org> > Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> > --- > 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 ee28253c9ac0..911db628092e 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -4815,10 +4815,10 @@ 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); > > @@ -4845,15 +4845,15 @@ 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; > @@ -4875,7 +4875,7 @@ __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); > } > @@ -4885,7 +4885,7 @@ 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; > > @@ -4902,12 +4902,12 @@ 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) > { > } > > @@ -6179,7 +6179,7 @@ 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) > { > @@ -7410,7 +7410,7 @@ 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 0ab79d819a0d..6498951b7d41 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 55f39c8f4203..ad020a2a72f3 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 e26688d387ae..54971a57a4ea 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -953,6 +953,12 @@ 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. > * > @@ -1051,7 +1057,7 @@ 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; > @@ -1559,7 +1565,7 @@ 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 > @@ -1739,7 +1745,7 @@ 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); > @@ -1752,7 +1758,7 @@ 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; > } > -- > 2.34.1 >
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ee28253c9ac0..911db628092e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4815,10 +4815,10 @@ 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); @@ -4845,15 +4845,15 @@ 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; @@ -4875,7 +4875,7 @@ __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); } @@ -4885,7 +4885,7 @@ 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; @@ -4902,12 +4902,12 @@ 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) { } @@ -6179,7 +6179,7 @@ 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) { @@ -7410,7 +7410,7 @@ 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 0ab79d819a0d..6498951b7d41 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 55f39c8f4203..ad020a2a72f3 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 e26688d387ae..54971a57a4ea 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -953,6 +953,12 @@ 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. * @@ -1051,7 +1057,7 @@ 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; @@ -1559,7 +1565,7 @@ 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 @@ -1739,7 +1745,7 @@ 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); @@ -1752,7 +1758,7 @@ 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; }
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@google.com> Link: https://github.com/ClangBuiltLinux/linux/issues/1724 Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> --- 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(-)