From: Matthew Wilcox <willy@infradead.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
torvalds@linux-foundation.org, peterz@infradead.org,
mingo@redhat.com, will@kernel.org, linux-kernel@vger.kernel.org,
joel@joelfernandes.org, alexander.levin@microsoft.com,
daniel.vetter@ffwll.ch, chris@chris-wilson.co.uk,
duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org,
tytso@mit.edu, david@fromorbit.com, amir73il@gmail.com,
bfields@fieldses.org, gregkh@linuxfoundation.org,
kernel-team@lge.com
Subject: Re: [RFC] Are you good with Lockdep?
Date: Wed, 18 Nov 2020 03:30:05 +0000 [thread overview]
Message-ID: <20201118033005.GD29991@casper.infradead.org> (raw)
In-Reply-To: <20201118014540.GA1278700@boqun-archlinux>
On Wed, Nov 18, 2020 at 09:45:40AM +0800, Boqun Feng wrote:
> Hi Matthew,
>
> On Mon, Nov 16, 2020 at 03:37:29PM +0000, Matthew Wilcox wrote:
> [...]
> >
> > It's not just about lockdep for semaphores. Mutexes will spin if the
> > current owner is still running, so to convert an interrupt-released
> > semaphore to a mutex, we need a way to mark the mutex as being released
>
> Could you provide an example for the conversion from interrupt-released
> semaphore to a mutex? I'd like to see if we can improve lockdep to help
> on that case.
How about adb_probe_mutex in drivers/macintosh/adb.c. Most of
the acquires/releases are within the same task. But adb_reset_bus()
calls down(&adb_probe_mutex), then schedules adb_reset_work() which runs
adb_probe_task() which calls up(&adb_probe_mutex).
Ideally adb_probe_mutex would become a mutex instead of the semaphore
it currently is. adb_reset_bus() would pass ownership of the mutex to
kadbprobe since it's the one which must run in order to release the mutex.
next prev parent reply other threads:[~2020-11-18 3:30 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 5:05 [RFC] Are you good with Lockdep? Byungchul Park
2020-11-11 10:54 ` Ingo Molnar
2020-11-11 14:36 ` Steven Rostedt
2020-11-11 23:16 ` Thomas Gleixner
2020-11-12 8:10 ` Byungchul Park
2020-11-12 14:26 ` Steven Rostedt
2020-11-12 14:52 ` Matthew Wilcox
2020-11-16 8:57 ` Byungchul Park
2020-11-16 15:37 ` Matthew Wilcox
2020-11-18 1:45 ` Boqun Feng
2020-11-18 3:30 ` Matthew Wilcox [this message]
2020-11-23 13:15 ` Byungchul Park
2020-11-12 14:58 ` Byungchul Park
2020-11-16 9:05 ` Byungchul Park
2020-11-23 10:45 ` Byungchul Park
2020-11-12 10:32 ` Byungchul Park
2020-11-12 13:56 ` Daniel Vetter
2020-11-16 8:45 ` Byungchul Park
2020-11-12 6:15 ` Byungchul Park
2020-11-12 8:51 ` Byungchul Park
2020-11-12 9:46 ` Byungchul Park
2020-11-23 11:05 ` [RFC] Dept(Dependency Tracker) Implementation Byungchul Park
2020-11-23 11:36 ` [RFC 1/6] dept: Implement Dept(Dependency Tracker) Byungchul Park
2020-11-23 11:36 ` [RFC 2/6] dept: Apply Dept to spinlock Byungchul Park
2020-11-23 11:36 ` [RFC 3/6] dept: Apply Dept to mutex families Byungchul Park
2020-11-23 11:36 ` [RFC 4/6] dept: Apply Dept to rwlock Byungchul Park
2020-11-23 11:36 ` [RFC 5/6] dept: Apply Dept to wait_for_completion()/complete() Byungchul Park
2020-11-23 11:36 ` [RFC 6/6] dept: Assign custom dept_keys or disable to avoid false positives Byungchul Park
2020-11-23 12:29 ` [RFC] Dept(Dependency Tracker) Implementation Byungchul Park
2020-11-23 11:13 ` [RFC] Dept(Dependency Tracker) Report Example Byungchul Park
2020-11-23 12:14 ` Byungchul Park
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