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authorBen Hutchings <ben@decadent.org.uk>2017-05-25 12:58:33 +0000
committerIngo Molnar <mingo@kernel.org>2017-06-05 09:28:03 +0200
commit98dcea0cfd04e083ac74137ceb9a632604740e2d (patch)
treec93a0600dc43a829c1c3152b15942bccd5adbb5a
parent3752466b6bf04868296ac6bc27ea1765008636d8 (diff)
downloadlinux-98dcea0cfd04e083ac74137ceb9a632604740e2d.tar.bz2
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 <ben@decadent.org.uk> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: <stable@vger.kernel.org> # for versions before 4.6, use a value of 255 Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/20170525130005.5947-3-alexander.levin@verizon.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--tools/lib/lockdep/uinclude/linux/lockdep.h2
1 files changed, 1 insertions, 1 deletions
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 <linux/utsname.h>
#include <linux/compiler.h>
-#define MAX_LOCK_DEPTH 2000UL
+#define MAX_LOCK_DEPTH 63UL
#define asmlinkage
#define __visible