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| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2010-04-20 16:23:07 +0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-05-10 11:08:31 -0700 |
| commit | 2b3fc35f6919344e3cf722dde8308f47235c0b70 (patch) | |
| tree | 2bc2cfc9c1a032d51a3d99a10e309e100b9eea4a /lib | |
| parent | b57f95a38233a2e73b679bea4a5453a1cc2a1cc9 (diff) | |
| download | lwn-2b3fc35f6919344e3cf722dde8308f47235c0b70.tar.gz lwn-2b3fc35f6919344e3cf722dde8308f47235c0b70.zip | |
rcu: optionally leave lockdep enabled after RCU lockdep splat
There is no need to disable lockdep after an RCU lockdep splat,
so remove the debug_lockdeps_off() from lockdep_rcu_dereference().
To avoid repeated lockdep splats, use a static variable in the inlined
rcu_dereference_check() and rcu_dereference_protected() macros so that
a given instance splats only once, but so that multiple instances can
be detected per boot.
This is controlled by a new config variable CONFIG_PROVE_RCU_REPEATEDLY,
which is disabled by default. This provides the normal lockdep behavior
by default, but permits people who want to find multiple RCU-lockdep
splats per boot to easily do so.
Requested-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 935248bdbc47..94090b4bb7d2 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -512,6 +512,18 @@ config PROVE_RCU Say N if you are unsure. +config PROVE_RCU_REPEATEDLY + bool "RCU debugging: don't disable PROVE_RCU on first splat" + depends on PROVE_RCU + default n + help + By itself, PROVE_RCU will disable checking upon issuing the + first warning (or "splat"). This feature prevents such + disabling, allowing multiple RCU-lockdep warnings to be printed + on a single reboot. + + Say N if you are unsure. + config LOCKDEP bool depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |