3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> commit 66339c31bc3978d5fff9c4b4cb590a861def4db2 upstream. dl_bw_of() dereferences rq->rd which has to have RCU read lock held. Probability of use-after-free isn't zero here. Also add lockdep assert into dl_bw_cpus(). Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/sched/core.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1895,6 +1895,8 @@ unsigned long to_ratio(u64 period, u64 r #ifdef CONFIG_SMP inline struct dl_bw *dl_bw_of(int i) { + rcu_lockdep_assert(rcu_read_lock_sched_held(), + "sched RCU must be held"); return &cpu_rq(i)->rd->dl_bw; } @@ -1903,6 +1905,8 @@ static inline int dl_bw_cpus(int i) struct root_domain *rd = cpu_rq(i)->rd; int cpus = 0; + rcu_lockdep_assert(rcu_read_lock_sched_held(), + "sched RCU must be held"); for_each_cpu_and(i, rd->span, cpu_active_mask) cpus++; @@ -7458,6 +7462,8 @@ static int sched_dl_global_constraints(v int cpu, ret = 0; unsigned long flags; + rcu_read_lock(); + /* * Here we want to check the bandwidth not being set to some * value smaller than the currently allocated bandwidth in @@ -7479,6 +7485,8 @@ static int sched_dl_global_constraints(v break; } + rcu_read_unlock(); + return ret; } @@ -7494,6 +7502,7 @@ static void sched_dl_do_global(void) if (global_rt_runtime() != RUNTIME_INF) new_bw = to_ratio(global_rt_period(), global_rt_runtime()); + rcu_read_lock(); /* * FIXME: As above... */ @@ -7504,6 +7513,7 @@ static void sched_dl_do_global(void) dl_b->bw = new_bw; raw_spin_unlock_irqrestore(&dl_b->lock, flags); } + rcu_read_unlock(); } static int sched_rt_global_validate(void) -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html