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* [PATCH review for 4.4 01/26] locking/lockdep: Add nest_lock integrity test
@ 2017-09-25  1:13 Levin, Alexander (Sasha Levin)
  2017-09-25  1:13 ` [PATCH review for 4.4 04/26] mac80211_hwsim: check HWSIM_ATTR_RADIO_NAME length Levin, Alexander (Sasha Levin)
                   ` (24 more replies)
  0 siblings, 25 replies; 28+ messages in thread
From: Levin, Alexander (Sasha Levin) @ 2017-09-25  1:13 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Peter Zijlstra, Andrew Morton, Chris Wilson, Linus Torvalds,
	Nicolai Hähnle, Paul E . McKenney, Thomas Gleixner,
	Ingo Molnar, Levin, Alexander (Sasha Levin)

From: Peter Zijlstra <peterz@infradead.org>

[ Upstream commit 7fb4a2cea6b18dab56d609530d077f168169ed6b ]

Boqun reported that hlock->references can overflow. Add a debug test
for that to generate a clear error when this happens.

Without this, lockdep is likely to report a mysterious failure on
unlock.

Reported-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolai Hähnle <Nicolai.Haehnle@amd.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
---
 kernel/locking/lockdep.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 60ace56618f6..0e2c4911ba61 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3128,10 +3128,17 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 	if (depth) {
 		hlock = curr->held_locks + depth - 1;
 		if (hlock->class_idx == class_idx && nest_lock) {
-			if (hlock->references)
+			if (hlock->references) {
+				/*
+				 * Check: unsigned int references:12, overflow.
+				 */
+				if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1))
+					return 0;
+
 				hlock->references++;
-			else
+			} else {
 				hlock->references = 2;
+			}
 
 			return 1;
 		}
-- 
2.11.0

^ permalink raw reply	[flat|nested] 28+ messages in thread

end of thread, other threads:[~2017-09-25 14:35 UTC | newest]

Thread overview: 28+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-09-25  1:13 [PATCH review for 4.4 01/26] locking/lockdep: Add nest_lock integrity test Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 04/26] mac80211_hwsim: check HWSIM_ATTR_RADIO_NAME length Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 03/26] irqchip/crossbar: Fix incorrect type of local variables Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 02/26] watchdog: kempld: fix gcc-4.3 build Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 05/26] mac80211: fix power saving clients handling in iwlwifi Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 06/26] net/mlx4_en: fix overflow in mlx4_en_init_timestamp() Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 07/26] netfilter: nf_ct_expect: Change __nf_ct_expect_check() return value Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 08/26] iio: adc: xilinx: Fix error handling Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 09/26] Btrfs: send, fix failure to rename top level inode due to name collision Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 10/26] f2fs: do not wait for writeback in write_begin Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 12/26] sparc64: Migrate hvcons irq to panicked cpu Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 11/26] md/linear: shutup lockdep warnning Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 13/26] net/mlx4_core: Fix VF overwrite of module param which disables DMFS on new probed PFs Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 14/26] crypto: xts - Add ECB dependency Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 15/26] ocfs2/dlmglue: prepare tracking logic to avoid recursive cluster lock Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 18/26] net: mvpp2: release reference to txq_cpu[] entry after unmapping Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 17/26] scsi: scsi_dh_emc: return success in clariion_std_inquiry() Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 16/26] slub: do not merge cache if slub_debug contains a never-merge flag Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 19/26] i2c: at91: ensure state is restored after suspending Levin, Alexander (Sasha Levin)
2017-09-25  7:22   ` Alexandre Belloni
2017-09-25 14:33     ` Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 20/26] ceph: clean up unsafe d_parent accesses in build_dentry_path Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 22/26] uapi: fix linux/mroute6.h userspace compilation errors Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 23/26] target/iscsi: Fix unsolicited data seq_end_offset calculation Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 21/26] uapi: fix linux/rds.h userspace compilation errors Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 25/26] genirq: Clarify logic calculating bogus irqreturn_t values Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 24/26] nfsd/callback: Cleanup callback cred on shutdown Levin, Alexander (Sasha Levin)
2017-09-25  1:13 ` [PATCH review for 4.4 26/26] cpufreq: CPPC: add ACPI_PROCESSOR dependency Levin, Alexander (Sasha Levin)

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