diff options
author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-05-24 19:31:09 +0400 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-09-29 08:36:37 +0400 |
commit | b3fbab0571eb09746cc0283648165ec00efc8eb2 (patch) | |
tree | 63bc01cbf03a5df34a96af292a00df4a96dc148a /kernel/sched.c | |
parent | d5988af53102f3b73e5e0788be024ccfa51869de (diff) | |
download | linux-b3fbab0571eb09746cc0283648165ec00efc8eb2.tar.xz |
rcu: Restore checks for blocking in RCU read-side critical sections
Long ago, using TREE_RCU with PREEMPT would result in "scheduling
while atomic" diagnostics if you blocked in an RCU read-side critical
section. However, PREEMPT now implies TREE_PREEMPT_RCU, which defeats
this diagnostic. This commit therefore adds a replacement diagnostic
based on PROVE_RCU.
Because rcu_lockdep_assert() and lockdep_rcu_dereference() are now being
used for things that have nothing to do with rcu_dereference(), rename
lockdep_rcu_dereference() to lockdep_rcu_suspicious() and add a third
argument that is a string indicating what is suspicious. This third
argument is passed in from a new third argument to rcu_lockdep_assert().
Update all calls to rcu_lockdep_assert() to add an informative third
argument.
Also, add a pair of rcu_lockdep_assert() calls from within
rcu_note_context_switch(), one complaining if a context switch occurs
in an RCU-bh read-side critical section and another complaining if a
context switch occurs in an RCU-sched read-side critical section.
These are present only if the PROVE_RCU kernel parameter is enabled.
Finally, fix some checkpatch whitespace complaints in lockdep.c.
Again, you must enable PROVE_RCU to see these new diagnostics. But you
are enabling PROVE_RCU to check out new RCU uses in any case, aren't you?
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index ec5f472bc5b9..e24cebe0e6cb 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4237,6 +4237,7 @@ static inline void schedule_debug(struct task_struct *prev) */ if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) __schedule_bug(prev); + rcu_sleep_check(); profile_hit(SCHED_PROFILING, __builtin_return_address(0)); @@ -8230,6 +8231,7 @@ void __might_sleep(const char *file, int line, int preempt_offset) { static unsigned long prev_jiffy; /* ratelimiting */ + rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || system_state != SYSTEM_RUNNING || oops_in_progress) return; |