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| author |   Paul E. McKenney <paulmck@kernel.org> | 2021-04-05 09:47:59 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-05-10 16:22:54 -0700 |
| commit | 1feb2cc8db481b902272559ad7aae3c091762ad0 (patch) | |
| tree | 38ee8c9062b201de472d995ca4785989d0d61300 /kernel/locking | |
| parent | rcu: Add ->gp_max to show_rcu_gp_kthreads() output (diff) | |
| download | linux-dev-1feb2cc8db481b902272559ad7aae3c091762ad0.tar.xz linux-dev-1feb2cc8db481b902272559ad7aae3c091762ad0.zip | |
lockdep: Explicitly flag likely false-positive report
The reason that lockdep_rcu_suspicious() prints the value of debug_locks
is because a value of zero indicates a likely false positive. This can
work, but is a bit obtuse. This commit therefore explicitly calls out
the possibility of a false positive.
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 48d736aa03b2..d6c3c987009d 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -6393,6 +6393,7 @@ asmlinkage __visible void lockdep_sys_exit(void) void lockdep_rcu_suspicious(const char *file, const int line, const char *s) { struct task_struct *curr = current; + int dl = READ_ONCE(debug_locks); /* Note: the following can be executed concurrently, so be careful. */ pr_warn("\n"); @@ -6402,11 +6403,12 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s) pr_warn("-----------------------------\n"); pr_warn("%s:%d %s!\n", file, line, s); pr_warn("\nother info that might help us debug this:\n\n"); - pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n", + pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n%s", !rcu_lockdep_current_cpu_online() ? "RCU used illegally from offline CPU!\n" : "", - rcu_scheduler_active, debug_locks); + rcu_scheduler_active, dl, + dl ? "" : "Possible false positive due to lockdep disabling via debug_locks = 0\n"); /* * If a CPU is in the RCU-free window in idle (ie: in the section |