Commit-ID: 98dcea0cfd04e083ac74137ceb9a632604740e2d
Gitweb: http://git.kernel.org/tip/98dcea0cfd04e083ac74137ceb9a632604740e2d
Author: Ben Hutchings <[email protected]>
AuthorDate: Thu, 25 May 2017 12:58:33 +0000
Committer: Ingo Molnar <[email protected]>
CommitDate: Mon, 5 Jun 2017 09:28:03 +0200
tools/lib/lockdep: Reduce MAX_LOCK_DEPTH to avoid overflowing lock_chain/: Depth
liblockdep has been broken since commit 75dd602a5198 ("lockdep: Fix
lock_chain::base size"), as that adds a check that MAX_LOCK_DEPTH is
within the range of lock_chain::depth and in liblockdep it is much
too large.
That should have resulted in a compiler error, but didn't because:
- the check uses ARRAY_SIZE(), which isn't yet defined in liblockdep
so is assumed to be an (undeclared) function
- putting a function call inside a BUILD_BUG_ON() expression quietly
turns it into some nonsense involving a variable-length array
It did produce a compiler warning, but I didn't notice because
liblockdep already produces too many warnings if -Wall is enabled
(which I'll fix shortly).
Even before that commit, which reduced lock_chain::depth from 8 bits
to 6, MAX_LOCK_DEPTH was too large.
Signed-off-by: Ben Hutchings <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Cc: <[email protected]> # for versions before 4.6, use a value of 255
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
tools/lib/lockdep/uinclude/linux/lockdep.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/lockdep/uinclude/linux/lockdep.h
b/tools/lib/lockdep/uinclude/linux/lockdep.h
index c808c7d..d302142 100644
--- a/tools/lib/lockdep/uinclude/linux/lockdep.h
+++ b/tools/lib/lockdep/uinclude/linux/lockdep.h
@@ -8,7 +8,7 @@
#include <linux/utsname.h>
#include <linux/compiler.h>
-#define MAX_LOCK_DEPTH 2000UL
+#define MAX_LOCK_DEPTH 63UL
#define asmlinkage
#define __visible
