This is a note to let you know that I've just added the patch titled
sched: Use dl_bw_of() under RCU read lock
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-use-dl_bw_of-under-rcu-read-lock.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 66339c31bc3978d5fff9c4b4cb590a861def4db2 Mon Sep 17 00:00:00 2001
From: Kirill Tkhai <[email protected]>
Date: Mon, 22 Sep 2014 22:36:24 +0400
Subject: sched: Use dl_bw_of() under RCU read lock
From: Kirill Tkhai <[email protected]>
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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
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)
Patches currently in stable-queue which might be from [email protected] are
queue-3.14/sched-use-dl_bw_of-under-rcu-read-lock.patch
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