From: Waiman Long <llong@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-kernel@vger.kernel.org, Jann Horn <jannh@google.com>
Subject: Re: [PATCH] locking/mutex: Disable preemption in __mutex_unlock_slowpath()
Date: Wed, 9 Jul 2025 14:28:13 -0400 [thread overview]
Message-ID: <1f329aff-efd1-4996-9194-9e35030e9faa@redhat.com> (raw)
In-Reply-To: <CAHk-=whVBKwK83R_7+52qzZb3DpFWGG8L=V5bDG6VS44e3=1-A@mail.gmail.com>
On 7/9/25 2:21 PM, Linus Torvalds wrote:
> On Wed, 9 Jul 2025 at 11:19, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>> I absolutely detest the notion of "let's make locking be tied to
>> object lifetimes".
> Side note: I wonder if there's any way to detect this kind of race in general.
>
> And I suspect it would involve the exact *opposite* of your patch:
> make mutex_unlock() actively cause preemption after it has released
> the lock but before it has done the final accesses.
I think we can do a a cond_resched() under CONFIG_DEBUG_MUTEXES and
CONFIG_KASAN. We certainly don't want to do that with a production kernel.
Cheers,
Longman
next prev parent reply other threads:[~2025-07-09 18:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-09 18:05 Waiman Long
2025-07-09 18:19 ` Waiman Long
2025-07-09 18:19 ` Linus Torvalds
2025-07-09 18:21 ` Linus Torvalds
2025-07-09 18:28 ` Waiman Long [this message]
2025-07-09 18:28 ` Linus Torvalds
2025-07-09 19:42 ` Waiman Long
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