Patchwork [2/2] lockdep: Up MAX_LOCKDEP_CHAINS

login
register
mail settings
Submitter Daniel Vetter
Date Nov. 28, 2017, 5:07 p.m.
Message ID <20171128170707.32525-2-daniel.vetter@ffwll.ch>
Download mbox | patch
Permalink /patch/10080787/
State New
Headers show

Comments

Daniel Vetter - Nov. 28, 2017, 5:07 p.m.
cross-release ftl

Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Marta Lofstedt <marta.lofstedt@intel.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=103707
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 kernel/locking/lockdep_internals.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Chris Wilson - Nov. 28, 2017, 5:22 p.m.
Quoting Daniel Vetter (2017-11-28 17:07:07)
> cross-release ftl

Fwiw, this isn't cross-release but us reloading the module many times,
creating a whole host of new lockclasses. Even more fun is when the
module gets a slightly different address and the new lock address hashes
into an old lock...

I did think about a module-hook to revoke the stale lockclasses, but
that still leaves all the hashed chains.

This particular nuisance was temporarily pushed back by teaching igt not
to reload i915.ko on a whim.
-Chris
Daniel Vetter - Nov. 29, 2017, 8:02 a.m.
On Tue, Nov 28, 2017 at 05:22:00PM +0000, Chris Wilson wrote:
> Quoting Daniel Vetter (2017-11-28 17:07:07)
> > cross-release ftl
> 
> Fwiw, this isn't cross-release but us reloading the module many times,
> creating a whole host of new lockclasses. Even more fun is when the
> module gets a slightly different address and the new lock address hashes
> into an old lock...
> 
> I did think about a module-hook to revoke the stale lockclasses, but
> that still leaves all the hashed chains.
> 
> This particular nuisance was temporarily pushed back by teaching igt not
> to reload i915.ko on a whim.

Ah ... Added your explanation to the commit message, and I guess that just
means we'll have to carry it ourselves :-/

I'll still send them out if CI approves to lockdep folks, just as an fyi.
-Daniel

Patch

diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index d459d624ba2a..41630a5385c6 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -69,7 +69,7 @@  enum {
 #else
 #define MAX_LOCKDEP_ENTRIES	32768UL
 
-#define MAX_LOCKDEP_CHAINS_BITS	16
+#define MAX_LOCKDEP_CHAINS_BITS	17
 
 /*
  * Stack-trace: tightly packed array of stack backtrace