From: Waiman Long <longman@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Waiman Long <longman@redhat.com>
Subject: [RFC PATCH 07/12] locking/lockdep: Add support for nested terminal locks
Date: Thu, 8 Nov 2018 15:34:23 -0500 [thread overview]
Message-ID: <1541709268-3766-8-git-send-email-longman@redhat.com> (raw)
In-Reply-To: <1541709268-3766-1-git-send-email-longman@redhat.com>
There are use cases where we want to allow 2-level nesting of one
terminal lock underneath another one. So the terminal lock type is now
extended to support a new nested terminal lock where it can allow the
acquisition of another regular terminal lock underneath it.
Signed-off-by: Waiman Long <longman@redhat.com>
---
include/linux/lockdep.h | 9 ++++++++-
kernel/locking/lockdep.c | 15 +++++++++++++--
kernel/locking/lockdep_internals.h | 2 +-
3 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index c5ff8c5..ed4d177 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -147,12 +147,16 @@ struct lock_class_stats {
* 1) LOCKDEP_FLAG_NOVALIDATE: No full validation, just simple checks.
* 2) LOCKDEP_FLAG_TERMINAL: This is a terminal lock where lock/unlock on
* another lock within its critical section is not allowed.
+ * 3) LOCKDEP_FLAG_TERMINAL_NESTED: This is a terminal lock that allows
+ * one more regular terminal lock to be nested underneath it.
*/
#define LOCKDEP_FLAG_NOVALIDATE (1 << 0)
#define LOCKDEP_FLAG_TERMINAL (1 << 1)
+#define LOCKDEP_FLAG_TERMINAL_NESTED (1 << 2)
#define LOCKDEP_NOCHECK_FLAGS (LOCKDEP_FLAG_NOVALIDATE |\
- LOCKDEP_FLAG_TERMINAL)
+ LOCKDEP_FLAG_TERMINAL |\
+ LOCKDEP_FLAG_TERMINAL_NESTED)
/*
* Map the lock object (the lock instance) to the lock-class object.
@@ -314,6 +318,8 @@ extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
do { (lock)->dep_map.flags |= LOCKDEP_FLAG_NOVALIDATE; } while (0)
#define lockdep_set_terminal_class(lock) \
do { (lock)->dep_map.flags |= LOCKDEP_FLAG_TERMINAL; } while (0)
+#define lockdep_set_terminal_nested_class(lock) \
+ do { (lock)->dep_map.flags |= LOCKDEP_FLAG_TERMINAL_NESTED; } while (0)
/*
* Compare locking classes
@@ -431,6 +437,7 @@ static inline void lockdep_on(void)
#define lockdep_set_novalidate_class(lock) do { } while (0)
#define lockdep_set_terminal_class(lock) do { } while (0)
+#define lockdep_set_terminal_nested_class(lock) do { } while (0)
/*
* We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 02631a0..2b75613 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3268,13 +3268,24 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
class_idx = class - lock_classes + 1;
if (depth) {
+ int prev_type;
+
hlock = curr->held_locks + depth - 1;
/*
- * Warn if the previous lock is a terminal lock.
+ * Warn if the previous lock is a terminal lock or the
+ * previous lock is a nested terminal lock and the current
+ * one isn't a regular terminal lock.
*/
- if (DEBUG_LOCKS_WARN_ON(hlock_is_terminal(hlock)))
+ prev_type = hlock_is_terminal(hlock);
+ if (DEBUG_LOCKS_WARN_ON((prev_type == LOCKDEP_FLAG_TERMINAL) ||
+ ((prev_type == LOCKDEP_FLAG_TERMINAL_NESTED) &&
+ (flags_is_terminal(class->flags) !=
+ LOCKDEP_FLAG_TERMINAL)))) {
+ pr_warn("Terminal lock error: prev lock = %s, curr lock = %s\n",
+ hlock->instance->name, class->name);
return 0;
+ }
if (hlock->class_idx == class_idx && nest_lock) {
if (hlock->references) {
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 271fba8..abe646a 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -215,5 +215,5 @@ static inline unsigned long debug_class_ops_read(struct lock_class *class)
static inline unsigned int flags_is_terminal(unsigned int flags)
{
- return flags & LOCKDEP_FLAG_TERMINAL;
+ return flags & (LOCKDEP_FLAG_TERMINAL|LOCKDEP_FLAG_TERMINAL_NESTED);
}
--
1.8.3.1
next prev parent reply other threads:[~2018-11-08 20:35 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 20:34 [RFC PATCH 00/12] locking/lockdep: Add a new class of terminal locks Waiman Long
2018-11-08 20:34 ` [RFC PATCH 01/12] locking/lockdep: Rework lockdep_set_novalidate_class() Waiman Long
2018-11-10 14:14 ` Peter Zijlstra
2018-11-11 0:26 ` Waiman Long
2018-11-11 1:28 ` Peter Zijlstra
2018-11-08 20:34 ` [RFC PATCH 02/12] locking/lockdep: Add a new terminal lock type Waiman Long
2018-11-10 14:17 ` Peter Zijlstra
2018-11-11 0:28 ` Waiman Long
2018-11-08 20:34 ` [RFC PATCH 03/12] locking/lockdep: Add DEFINE_TERMINAL_SPINLOCK() and related macros Waiman Long
2018-11-08 20:34 ` [RFC PATCH 04/12] printk: Make logbuf_lock a terminal lock Waiman Long
2018-11-08 20:34 ` [RFC PATCH 05/12] debugobjects: Mark pool_lock as " Waiman Long
2018-11-08 20:34 ` [RFC PATCH 06/12] debugobjects: Move printk out of db lock critical sections Waiman Long
2018-11-08 20:34 ` Waiman Long [this message]
2018-11-10 14:20 ` [RFC PATCH 07/12] locking/lockdep: Add support for nested terminal locks Peter Zijlstra
2018-11-11 0:30 ` Waiman Long
2018-11-11 1:30 ` Peter Zijlstra
2018-11-08 20:34 ` [RFC PATCH 08/12] debugobjects: Make object hash locks " Waiman Long
2018-11-08 20:34 ` [RFC PATCH 09/12] lib/stackdepot: Make depot_lock a terminal spinlock Waiman Long
2018-11-08 20:34 ` [RFC PATCH 10/12] locking/rwsem: Mark rwsem.wait_lock as a terminal lock Waiman Long
2018-11-08 20:34 ` [RFC PATCH 11/12] cgroup: Mark the rstat percpu lock as terminal Waiman Long
2018-11-08 20:34 ` [RFC PATCH 12/12] mm/kasan: Make quarantine_lock a terminal lock Waiman Long
2018-11-09 8:04 ` [RFC PATCH 00/12] locking/lockdep: Add a new class of terminal locks Ingo Molnar
2018-11-09 15:48 ` Waiman Long
2018-11-12 5:15 ` Ingo Molnar
2018-11-10 14:10 ` Peter Zijlstra
2018-11-10 23:35 ` Waiman Long
2018-11-12 5:10 ` Ingo Molnar
2018-11-12 5:53 ` Josh Poimboeuf
2018-11-12 6:30 ` Ingo Molnar
2018-11-12 22:22 ` Josh Poimboeuf
2018-11-12 22:56 ` Waiman Long
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1541709268-3766-8-git-send-email-longman@redhat.com \
--to=longman@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=aryabinin@virtuozzo.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pmladek@suse.com \
--cc=sergey.senozhatsky@gmail.com \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).