From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5CC83E7717F for ; Fri, 13 Dec 2024 13:13:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=oIvx1QOmnoMjv+UcZ5OW36K4SsjomKKCLj0cIrmikGw=; b=quepOQeIhWsDHVAuKs4oruLjD3 DtY8bh5VRZi2rodMyNfxaXOEKGm5yMtiuVG9dGYqr6HH/h6+WkiYhgpnNt0oR2EO2qiCEYXB03ttT AW0gbX0nSqAu5JyUqSqEPmvmLOiqL24F/Hss8fVxnDnBM+Frns5GLESaOoaMg+gSfnzgWW0u0XQ5e 5dPzBJ7Ewva7zva+bS7qcHPasdhpfZ6mi7berj6k5+8Ulcf/IhyiUxMdtBal/q6d2LQFU/8Jj8f6e P7m2f6BlHOprwO7b4eDq5i7qRw+xy1zjuPLSgIKgXliGYhXJd/E6pqJCwdH3Bmb4hjbjAZ12sPL9n l1acvmWw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tM5UD-00000003noV-1785; Fri, 13 Dec 2024 13:13:41 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tM5UA-00000003nmh-0KHF for kexec@lists.infradead.org; Fri, 13 Dec 2024 13:13:39 +0000 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1734095616; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=oIvx1QOmnoMjv+UcZ5OW36K4SsjomKKCLj0cIrmikGw=; b=1PT8OqZP4YlYwzKN/9RwGZtgfH8YkO/Yfeu8wJPzgbOQMOf5P59wFBbtNVmF0J7XJbkr+5 QnBolz+g+WURuyPH3hgDypXOYVKMY2e0PxLTiKz2EL0MBeNWqn/gP9jtFhwQJpWoUrS/F5 6GMDJClGh+mwLBDzHQ6PBQnyfKnjnkVYTiKgZnJIIjGc3GmBOHdfYQjVnhXaA2AblHqPbK 9zZbiFNW6LHQee7WRfdUbWTpxv/DWSHbyv9EX8S+q7c0/rY5WA1y30tGFFBaLNg5qEAvXu YbEAvGNJf5KgHq+8InbMWfFnqoH9D/67YyKNgZqMlCRHTssk4nsAub3lbC8sug== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1734095616; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=oIvx1QOmnoMjv+UcZ5OW36K4SsjomKKCLj0cIrmikGw=; b=Fz9B86tyD74Nta+QP4pC570ZJoZV5oa40phqYQC0eog9H2qWxA9VTZrbfFUenXoYb86oiV ED/q3tX5yJt6vRCw== To: Peter Zijlstra Cc: David Woodhouse , Stefan Hajnoczi , Jason Wang , "x86@kernel.org" , hpa , dyoung , kexec , linux-ext4 , "Michael S. Tsirkin" , Stefano Garzarella , eperezma , Paolo Bonzini , ming.lei@redhat.com, Petr Mladek , John Ogness Subject: Re: Lockdep warnings on kexec (virtio_blk, hrtimers) In-Reply-To: <20241213112028.GE21636@noisy.programming.kicks-ass.net> References: <1f631458c180c975c238d4d33d333f9fa9a4d2a3.camel@infradead.org> <20241211124240.GA310916@fedora> <7717fe2ac0ce5f0a2c43fdab8b11f4483d54a2a4.camel@infradead.org> <87ldwl9g93.ffs@tglx> <10f5d22150b548ec271e0a847ba2eb91139e6f61.camel@infradead.org> <87a5d0aibc.ffs@tglx> <874j38a16p.ffs@tglx> <20241213112028.GE21636@noisy.programming.kicks-ass.net> Date: Fri, 13 Dec 2024 14:13:36 +0100 Message-ID: <87seqr914v.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241213_051338_251606_554E9845 X-CRM114-Status: GOOD ( 11.34 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Fri, Dec 13 2024 at 12:20, Peter Zijlstra wrote: > On Fri, Dec 13, 2024 at 01:14:54AM +0100, Thomas Gleixner wrote: > >> --- a/kernel/sched/core.c >> +++ b/kernel/sched/core.c >> @@ -7276,7 +7276,7 @@ void rt_mutex_setprio(struct task_struct >> #if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) >> int __sched __cond_resched(void) >> { >> - if (should_resched(0)) { >> + if (should_resched(0) && system_state != SYSTEM_SUSPEND) { >> preempt_schedule_common(); >> return 1; >> } > > Perhaps we should just do: > > if (should_resched(0) && !irqs_disabled()) > > That's more or less what preemptible() does too. Yes, mucking about with > IF is expensive, but it's only done if preempt_count is agreeing we > should schedule, which it shouldn't be most of the time. Makes sense. Let me write a real patch. Thanks, tglx