From: Oleg Nesterov <oleg@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] seqlock, procfs: Fix scoped_seqlock_read() critical section in do_task_stat()
Date: Tue, 2 Dec 2025 08:29:35 +0100 [thread overview]
Message-ID: <aS6VX56DuPWY3bXk@redhat.com> (raw)
In-Reply-To: <aS5mdHYhHi9Gi5-r@gmail.com>
On 12/02, Ingo Molnar wrote:
>
> RCU read-lock should not nest inside a read-seqlock
> irqsave ->stats_lock IRQs-off critical section,
Hmm... I agree with this patch, but is it actually wrong?
I thought that rcu_read_lock/unlock is safe under spin_lock_irq...
> + {
> + guard(rcu)();
> + scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {
how about
scoped_guard(rcu) {
scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {
...
}
}
?
Oleg.
next prev parent reply other threads:[~2025-12-02 7:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-02 4:09 [PATCH] seqlock, procfs: Fix scoped_seqlock_read() critical section in do_task_stat() Ingo Molnar
2025-12-02 7:29 ` Oleg Nesterov [this message]
2025-12-02 9:05 ` [PATCH -v2] seqlock, procfs: Match scoped_seqlock_read() critical section vs. RCU ordering in do_task_stat() to do_io_accounting() Ingo Molnar
2025-12-02 9:21 ` Oleg Nesterov
2025-12-02 10:18 ` Ingo Molnar
2025-12-02 10:23 ` [tip: locking/urgent] " tip-bot2 for Ingo Molnar
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