From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
Amol Grover <frextrite@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 21/30] rculist: Add brackets around cond argument in __list_check_rcu macro
Date: Fri, 14 Feb 2020 15:55:58 -0800 [thread overview]
Message-ID: <20200214235607.13749-21-paulmck@kernel.org> (raw)
In-Reply-To: <20200214235536.GA13364@paulmck-ThinkPad-P72>
From: Amol Grover <frextrite@gmail.com>
Passing a complex lockdep condition to __list_check_rcu results
in false positive lockdep splat due to incorrect expression
evaluation.
For example, a lockdep check condition `cond1 || cond2` is
evaluated as `!cond1 || cond2 && !rcu_read_lock_any_held()`
which, according to operator precedence, evaluates to
`!cond1 || (cond2 && !rcu_read_lock_any_held())`.
This would result in a lockdep splat when cond1 is false
and cond2 is true which is logically incorrect.
Signed-off-by: Amol Grover <frextrite@gmail.com>
Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
include/linux/rculist.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index 9f313e4..8214cdc 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -60,9 +60,9 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
#define __list_check_rcu(dummy, cond, extra...) \
({ \
check_arg_count_one(extra); \
- RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \
+ RCU_LOCKDEP_WARN(!(cond) && !rcu_read_lock_any_held(), \
"RCU-list traversed in non-reader section!"); \
- })
+ })
#else
#define __list_check_rcu(dummy, cond, extra...) \
({ check_arg_count_one(extra); })
--
2.9.5
next prev parent reply other threads:[~2020-02-14 23:57 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-14 23:55 [PATCH tip/core/rcu 0/30] Miscellaneous fixes for v5.7 Paul E. McKenney
2020-02-14 23:55 ` [PATCH tip/core/rcu 01/30] nfs: Fix nfs_access_get_cached_rcu() sparse error paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 02/30] rcu: Warn on for_each_leaf_node_cpu_mask() from non-leaf paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 03/30] rcu: Fix exp_funnel_lock()/rcu_exp_wait_wake() datarace paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 04/30] rcu: Provide debug symbols and line numbers in KCSAN runs paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 05/30] rcu: Add WRITE_ONCE() to rcu_node ->qsmask update paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 06/30] rcu: Add WRITE_ONCE to rcu_node ->exp_seq_rq store paulmck
2020-02-15 3:47 ` Steven Rostedt
2020-02-15 10:58 ` Paul E. McKenney
2020-02-17 21:11 ` Joel Fernandes
2020-02-17 21:36 ` Paul E. McKenney
2020-02-14 23:55 ` [PATCH tip/core/rcu 07/30] rcu: Add READ_ONCE() to rcu_node ->gp_seq paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 08/30] rcu: Add WRITE_ONCE() to rcu_state ->gp_req_activity paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 09/30] rcu: Add WRITE_ONCE() to rcu_node ->qsmaskinitnext paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 10/30] locking/rtmutex: rcu: Add WRITE_ONCE() to rt_mutex ->owner paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 11/30] rcu: Add READ_ONCE() to rcu_segcblist ->tails[] paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 12/30] rcu: *_ONCE() for grace-period progress indicators paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 13/30] rcu: Fix typos in beginning comments paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 14/30] rcu: Add READ_ONCE() to rcu_data ->gpwrap paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 15/30] rcu: Add *_ONCE() to rcu_data ->rcu_forced_tick paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 16/30] rcu: Add *_ONCE() to rcu_node ->boost_kthread_status paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 17/30] timer: Use hlist_unhashed_lockless() in timer_pending() paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 18/30] rcu: Remove dead code from rcu_segcblist_insert_pend_cbs() paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 19/30] rcu: Add WRITE_ONCE() to rcu_state ->gp_start paulmck
2020-02-14 23:55 ` [PATCH tip/core/rcu 20/30] rcu: Fix rcu_barrier_callback() race condition paulmck
2020-02-14 23:55 ` paulmck [this message]
2020-02-14 23:55 ` [PATCH tip/core/rcu 22/30] rcu: Don't flag non-starting GPs before GP kthread is running paulmck
2020-02-15 3:53 ` Steven Rostedt
2020-02-15 11:01 ` Paul E. McKenney
2020-02-15 13:42 ` Paul E. McKenney
2020-02-17 20:25 ` Steven Rostedt
2020-02-17 22:03 ` Paul E. McKenney
2020-02-17 22:21 ` Steven Rostedt
2020-02-17 23:03 ` Paul E. McKenney
2020-02-14 23:56 ` [PATCH tip/core/rcu 23/30] rcu: Add missing annotation for rcu_nocb_bypass_lock() paulmck
2020-02-14 23:56 ` [PATCH tip/core/rcu 24/30] rcu/nocb: Add missing annotation for rcu_nocb_bypass_unlock() paulmck
2020-02-14 23:56 ` [PATCH tip/core/rcu 25/30] rcu: Optimize and protect atomic_cmpxchg() loop paulmck
2020-02-14 23:56 ` [PATCH tip/core/rcu 26/30] rcu: Tighten rcu_lockdep_assert_cblist_protected() check paulmck
2020-02-14 23:56 ` [PATCH tip/core/rcu 27/30] rcu: Make nocb_gp_wait() double-check unexpected-callback warning paulmck
2020-02-14 23:56 ` [PATCH tip/core/rcu 28/30] rcu: Mark rcu_state.ncpus to detect concurrent writes paulmck
2020-02-14 23:56 ` [PATCH tip/core/rcu 29/30] rcu: Mark rcu_state.gp_seq " paulmck
2020-02-14 23:56 ` [PATCH tip/core/rcu 30/30] rcu: Make rcu_barrier() account for offline no-CBs CPUs paulmck
2020-02-25 10:24 ` Boqun Feng
2020-02-26 3:14 ` Paul E. McKenney
2020-02-26 4:18 ` Paul E. McKenney
2020-02-26 6:14 ` Boqun Feng
2020-02-26 15:02 ` Paul E. McKenney
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