From: Ben Hutchings Date: Tue, 14 Jun 2016 20:44:14 +0100 Subject: [PATCH 2/7] liblockdep: Reduce MAX_LOCK_DEPTH to avoid overflowing lock_chain::depth Forwarded: http://mid.gmane.org/20160614204752.GU7555@decadent.org.uk 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. Cc: # for versions before 4.6, use a value of 255 Signed-off-by: Ben Hutchings --- 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 c808c7d02d21..d30214221920 100644 --- a/tools/lib/lockdep/uinclude/linux/lockdep.h +++ b/tools/lib/lockdep/uinclude/linux/lockdep.h @@ -8,7 +8,7 @@ #include #include -#define MAX_LOCK_DEPTH 2000UL +#define MAX_LOCK_DEPTH 63UL #define asmlinkage #define __visible