Eric Lee / linux-smarc-t335x-v3.2

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Commit bc293d62b26ec590afc90a9e0a31c45d355b7bd8

Authored by Paul E. McKenney
Committed by Ingo Molnar
1 parent 50aec0024e
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

rcu: Make RCU lockdep check the lockdep_recursion variable 

The lockdep facility temporarily disables lockdep checking by
incrementing the current->lockdep_recursion variable.  Such
disabling happens in NMIs and in other situations where lockdep
might expect to recurse on itself.

This patch therefore checks current->lockdep_recursion, disabling RCU
lockdep splats when this variable is non-zero.  In addition, this patch
removes the "likely()", as suggested by Lai Jiangshan.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: David Miller <davem@davemloft.net>
Tested-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <20100415195039.GA22623@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 2 changed files with 8 additions and 4 deletions Side-by-side Diff

include/linux/rcupdate.h
Diff comments   View file @ bc293d6
... ... @@ -101,10 +101,7 @@
101 101 # define rcu_read_release_sched() \
102 102 lock_release(&rcu_sched_lock_map, 1, _THIS_IP_)
103 103  
104   -static inline int debug_lockdep_rcu_enabled(void)
105   -{
106   - return likely(rcu_scheduler_active && debug_locks);
107   -}
  104 +extern int debug_lockdep_rcu_enabled(void);
108 105  
109 106 /**
110 107 * rcu_read_lock_held - might we be in RCU read-side critical section?
... ... @@ -69,6 +69,13 @@
69 69  
70 70 #ifdef CONFIG_DEBUG_LOCK_ALLOC
71 71  
  72 +int debug_lockdep_rcu_enabled(void)
  73 +{
  74 + return rcu_scheduler_active && debug_locks &&
  75 + current->lockdep_recursion == 0;
  76 +}
  77 +EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
  78 +
72 79 /**
73 80 * rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section?
74 81 *