From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kobe Wu Subject: [PATCH] locking/lockdep: Fix UBSAN warnings Date: Wed, 12 Jun 2019 13:49:04 +0800 Message-ID: <1560318544-27635-1-git-send-email-kobe-cp.wu@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+glpam-linux-mediatek=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Peter Zijlstra , Ingo Molnar , Will Deacon Cc: Eason Lin , linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, wsd_upstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, Kobe Wu List-Id: linux-mediatek@lists.infradead.org Fix complaints from UBSAN about signed integer overflow. ======================================================================== UBSAN: Undefined behaviour in kernel/locking/lockdep.c:2998:3 signed integer overflow: 2147483647 + 1 cannot be represented in type 'int' Call trace: dump_backtrace+0x0/0x470 show_stack+0x14/0x20 dump_stack+0xc8/0x11c ubsan_epilogue+0x14/0xa8 handle_overflow+0x138/0x1a8 __ubsan_handle_add_overflow+0x10/0x18 trace_hardirqs_off_caller+0x1a0/0x268 trace_hardirqs_off+0x1c/0x28 rcu_irq_enter_irqson+0x18/0x50 handle_IPI+0x4cc/0x898 gic_handle_irq+0x1f4/0x240 When system has been running for a long time, signed integer counters are not enough for some lockdep statistics. Such as the warning above, it occurs at debug_atomic_inc(hardirqs_off_events). Using unsigned long counters can satisfy the requirement. Besides, most of other lockdep statistics are unsigned. It is better to use unsigned int instead of int. Remove unused variables. - max_recursion_depth - nr_cyclic_check_recursions - nr_find_usage_forwards_recursions - nr_find_usage_backwards_recursions Signed-off-by: Kobe Wu --- kernel/locking/lockdep_internals.h | 36 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 20 deletions(-) diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index 150ec3f..cc83568 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -131,7 +131,6 @@ extern void get_usage_chars(struct lock_class *class, extern unsigned int nr_softirq_chains; extern unsigned int nr_process_chains; extern unsigned int max_lockdep_depth; -extern unsigned int max_recursion_depth; extern unsigned int max_bfs_queue_depth; @@ -160,25 +159,22 @@ extern void get_usage_chars(struct lock_class *class, * and we want to avoid too much cache bouncing. */ struct lockdep_stats { - int chain_lookup_hits; - int chain_lookup_misses; - int hardirqs_on_events; - int hardirqs_off_events; - int redundant_hardirqs_on; - int redundant_hardirqs_off; - int softirqs_on_events; - int softirqs_off_events; - int redundant_softirqs_on; - int redundant_softirqs_off; - int nr_unused_locks; - int nr_redundant_checks; - int nr_redundant; - int nr_cyclic_checks; - int nr_cyclic_check_recursions; - int nr_find_usage_forwards_checks; - int nr_find_usage_forwards_recursions; - int nr_find_usage_backwards_checks; - int nr_find_usage_backwards_recursions; + unsigned long chain_lookup_hits; + unsigned int chain_lookup_misses; + unsigned long hardirqs_on_events; + unsigned long hardirqs_off_events; + unsigned long redundant_hardirqs_on; + unsigned long redundant_hardirqs_off; + unsigned long softirqs_on_events; + unsigned long softirqs_off_events; + unsigned long redundant_softirqs_on; + unsigned long redundant_softirqs_off; + int nr_unused_locks; + unsigned int nr_redundant_checks; + unsigned int nr_redundant; + unsigned int nr_cyclic_checks; + unsigned int nr_find_usage_forwards_checks; + unsigned int nr_find_usage_backwards_checks; /* * Per lock class locking operation stat counts -- 1.7.9.5