On Wed, 2017-07-05 at 11:20 -0400, Steven Rostedt wrote:
On Wed, 05 Jul 2017 08:09:49 -0700
James Bottomley [off-list ref] wrote:
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you're protecting was accessed outside the lock, which is the
usual source of concurrency problems. In other words lockdep
is useful but it's not a panacea.
Still not an excuse to not have lockdep enabled during tests.
OK, what makes you think lockdep isn't enabled? Since Kconfig is
so complex, I usually use a distro config ... they have it enabled
(or at least openSUSE does), so it's enabled for everything I do.
openSuSE has it enabled? I hope not for its production config, as
lockdep has a huge performance penalty.
Then, surely, it's the last thing we want when tracking down race
conditgions since it will alter timings dramatically.
I'm thinking you don't have it enabled. What config are you looking
at? The actual config that does the testing of locks is
CONFIG_PROVE_LOCKING, which selects LOCKDEP to be compiled in.
This is what it has:
jejb@jarvis:~/git/linux-build> grep LOCKDEP /boot/config-4.4.73-18.17-default
CONFIG_LOCKDEP_SUPPORT=y
James