CONFIG_LOCKDEP_CROSSRELEASE and CONFIG_LOCKDEP_COMPLETIONS can result in a large number of false positives because lockdep doesn't understand how to deal with multiple stacked loop or MD devices. Until someone can figure out how to automatically add annotations to all file system and storage devices --- hopefully without forcing developers to insert a large number of calls to undocumented lockdep macros into the the loop device, every single file system, and every single device-mapper backend --- let's add an option to allow these lockdep features to be disabled. Otherwise, many file system developers will disable LOCKDEP entirely since it results in far too many false positives when trying to use xfstests. Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Cc: Byungchul Park <byungchul.park@xxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: kernel-team@xxxxxxx Cc: linux-block@xxxxxxxxxxxxxxx Cc: linux-fsdevel@xxxxxxxxxxxxxxx Cc: oleg@xxxxxxxxxx Cc: tj@xxxxxxxxxx --- lib/Kconfig.debug | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 947d3e2ed5c2..acae7ba99c16 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1099,8 +1099,8 @@ config PROVE_LOCKING select DEBUG_MUTEXES select DEBUG_RT_MUTEXES if RT_MUTEXES select DEBUG_LOCK_ALLOC - select LOCKDEP_CROSSRELEASE - select LOCKDEP_COMPLETIONS + select LOCKDEP_CROSSRELEASE if LOCKDEP_AGGRESSIVE + select LOCKDEP_COMPLETIONS if LOCKDEP_AGGRESSIVE select TRACE_IRQFLAGS default n help @@ -1137,6 +1137,16 @@ config PROVE_LOCKING For more details, see Documentation/locking/lockdep-design.txt. +config LOCKDEP_AGGRESSIVE + bool "Lock debugging: use aggressive techniques" + default n + help + This enables some extremely aggressive lockdep checking that + may result in false positives. + + Say N here if you are planning on using xfstests and don't + want to deal with many false positive test failures. + config LOCKDEP bool depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT -- 2.11.0.rc0.7.gbe5a750
