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[PATCH 3.18 14/28] tools/lib/lockdep: Reduce MAX_LOCK_DEPTH to avoid overflowing lock_chain/: Depth

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3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben@decadent.org.uk>

commit 98dcea0cfd04e083ac74137ceb9a632604740e2d upstream.

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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/lib/lockdep/uinclude/linux/lockdep.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/lib/lockdep/uinclude/linux/lockdep.h
+++ b/tools/lib/lockdep/uinclude/linux/lockdep.h
@@ -8,7 +8,7 @@
 #include <linux/utsname.h>
 
 
-#define MAX_LOCK_DEPTH 2000UL
+#define MAX_LOCK_DEPTH 255UL
 
 #define asmlinkage
 #define __visible

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[PATCH 3.18 00/28] 3.18.62-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:20 +0200
  [PATCH 3.18 22/28] crypto: atmel - only treat EBUSY as transient if backlog Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:20 +0200
  [PATCH 3.18 25/28] sched/topology: Optimize build_group_mask() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:20 +0200
  [PATCH 3.18 16/28] fs/dcache.c: fix spin lockup issue on nlru->lock Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:20 +0200
  [PATCH 3.18 19/28] vt: fix unchecked __put_user() in tioclinux ioctls Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:20 +0200
  [PATCH 3.18 12/28] parisc: DMA API: return error instead of BUG_ON for dma ops on non dma devs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:20 +0200
  [PATCH 3.18 08/28] cfg80211: Check if PMKID attribute is of expected size Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 09/28] irqchip/gic-v3: Fix out-of-bound access in gic_set_affinity Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 03/28] net: prevent sign extension in dev_get_stats() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 14/28] tools/lib/lockdep: Reduce MAX_LOCK_DEPTH to avoid overflowing lock_chain/: Depth Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 23/28] crypto: sha1-ssse3 - Disable avx2 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 07/28] cfg80211: Validate frequencies nested in NL80211_ATTR_SCAN_FREQUENCIES Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 01/28] ipv6: avoid unregistering inet6_dev for loopback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 04/28] ipv6: dad: dont remove dynamic addresses if link is down Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  [PATCH 3.18 11/28] parisc: use compat_sys_keyctl() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-19 13:30 +0200
  Re: [PATCH 3.18 00/28] 3.18.62-stable review Guenter Roeck <linux@roeck-us.net> - 2017-07-19 22:40 +0200
  Re: [PATCH 3.18 00/28] 3.18.62-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-07-20 01:50 +0200
    Re: [PATCH 3.18 00/28] 3.18.62-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-20 07:10 +0200

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