From: "tip-bot2 for Xiongwei Song" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Xiongwei Song <sxwjean@gmail.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Waiman Long <longman@redhat.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: locking/urgent] locking/lockdep: Fix meaningless /proc/lockdep output of lock classes on !CONFIG_PROVE_LOCKING
Date: Mon, 05 Jul 2021 09:05:19 -0000 [thread overview]
Message-ID: <162547591914.395.12424245649522104664.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210629135916.308210-1-sxwjean@me.com>
The following commit has been merged into the locking/urgent branch of tip:
Commit-ID: 4840ce2267f9d887f333d88a037c82c566f84081
Gitweb: https://git.kernel.org/tip/4840ce2267f9d887f333d88a037c82c566f84081
Author: Xiongwei Song <sxwjean@gmail.com>
AuthorDate: Tue, 29 Jun 2021 21:59:16 +08:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 05 Jul 2021 10:44:52 +02:00
locking/lockdep: Fix meaningless /proc/lockdep output of lock classes on !CONFIG_PROVE_LOCKING
When enabling CONFIG_LOCK_STAT=y, then CONFIG_LOCKDEP=y is forcedly enabled,
but CONFIG_PROVE_LOCKING is disabled.
We can get output from /proc/lockdep, which currently includes usages of
lock classes. But the usages are meaningless, see the output below:
/ # cat /proc/lockdep
all lock classes:
ffffffff9af63350 ....: cgroup_mutex
ffffffff9af54eb8 ....: (console_sem).lock
ffffffff9af54e60 ....: console_lock
ffffffff9ae74c38 ....: console_owner_lock
ffffffff9ae74c80 ....: console_owner
ffffffff9ae66e60 ....: cpu_hotplug_lock
Only one usage context for each lock, this is because each usage is only
changed in mark_lock() that is in the CONFIG_PROVE_LOCKING=y section,
however in the test situation, it's not.
The fix is to move the usages reading and seq_print from the
!CONFIG_PROVE_LOCKING section to its defined section.
Also, locks_after list of lock_class is empty when !CONFIG_PROVE_LOCKING,
so do the same thing as what have done for usages of lock classes.
With this patch with !CONFIG_PROVE_LOCKING we can get the results below:
/ # cat /proc/lockdep
all lock classes:
ffffffff85163290: cgroup_mutex
ffffffff85154dd8: (console_sem).lock
ffffffff85154d80: console_lock
ffffffff85074b58: console_owner_lock
ffffffff85074ba0: console_owner
ffffffff85066d60: cpu_hotplug_lock
... a class key and the relevant class name each line.
Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20210629135916.308210-1-sxwjean@me.com
---
kernel/locking/lockdep_proc.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 8069783..b8d9a05 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -70,26 +70,28 @@ static int l_show(struct seq_file *m, void *v)
#ifdef CONFIG_DEBUG_LOCKDEP
seq_printf(m, " OPS:%8ld", debug_class_ops_read(class));
#endif
-#ifdef CONFIG_PROVE_LOCKING
- seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
- seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
-#endif
+ if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
+ seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
+ seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
- get_usage_chars(class, usage);
- seq_printf(m, " %s", usage);
+ get_usage_chars(class, usage);
+ seq_printf(m, " %s", usage);
+ }
seq_printf(m, ": ");
print_name(m, class);
seq_puts(m, "\n");
- list_for_each_entry(entry, &class->locks_after, entry) {
- if (entry->distance == 1) {
- seq_printf(m, " -> [%p] ", entry->class->key);
- print_name(m, entry->class);
- seq_puts(m, "\n");
+ if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
+ list_for_each_entry(entry, &class->locks_after, entry) {
+ if (entry->distance == 1) {
+ seq_printf(m, " -> [%p] ", entry->class->key);
+ print_name(m, entry->class);
+ seq_puts(m, "\n");
+ }
}
+ seq_puts(m, "\n");
}
- seq_puts(m, "\n");
return 0;
}
prev parent reply other threads:[~2021-07-05 9:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-29 13:59 [PATCH v3] locking/lockdep: Fix meaningless usages output of lock classes Xiongwei Song
2021-06-29 14:02 ` Waiman Long
2021-07-05 7:53 ` [tip: locking/urgent] " tip-bot2 for Xiongwei Song
2021-07-05 9:05 ` tip-bot2 for Xiongwei Song [this message]
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