45 lines
1.6 KiB
Diff
45 lines
1.6 KiB
Diff
From: Ben Hutchings <ben@decadent.org.uk>
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Date: Tue, 14 Jun 2016 20:44:14 +0100
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Subject: [PATCH 2/7] liblockdep: Reduce MAX_LOCK_DEPTH to avoid overflowing
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lock_chain::depth
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Forwarded: http://mid.gmane.org/20160614204752.GU7555@decadent.org.uk
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liblockdep has been broken since commit 75dd602a5198 ("lockdep: Fix
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lock_chain::base size"), as that adds a check that MAX_LOCK_DEPTH is
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within the range of lock_chain::depth and in liblockdep it is much
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too large.
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That should have resulted in a compiler error, but didn't because:
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- the check uses ARRAY_SIZE(), which isn't yet defined in liblockdep
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so is assumed to be an (undeclared) function
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- putting a function call inside a BUILD_BUG_ON() expression quietly
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turns it into some nonsense involving a variable-length array
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It did produce a compiler warning, but I didn't notice because
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liblockdep already produces too many warnings if -Wall is enabled
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(which I'll fix shortly).
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Even before that commit, which reduced lock_chain::depth from 8 bits
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to 6, MAX_LOCK_DEPTH was too large.
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Cc: <stable@vger.kernel.org> # for versions before 4.6, use a value of 255
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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---
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tools/lib/lockdep/uinclude/linux/lockdep.h | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/tools/lib/lockdep/uinclude/linux/lockdep.h b/tools/lib/lockdep/uinclude/linux/lockdep.h
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index c808c7d02d21..d30214221920 100644
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--- a/tools/lib/lockdep/uinclude/linux/lockdep.h
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+++ b/tools/lib/lockdep/uinclude/linux/lockdep.h
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@@ -8,7 +8,7 @@
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#include <linux/utsname.h>
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#include <linux/compiler.h>
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-#define MAX_LOCK_DEPTH 2000UL
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+#define MAX_LOCK_DEPTH 63UL
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#define asmlinkage
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#define __visible
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