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From: "zoudongjie (A)" <zoudongjie@huawei.com>
To: "seanjc@google.com" <seanjc@google.com>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "Chenzhendong (alex)" <alex.chen@huawei.com>,
	luolongmin <luolongmin@huawei.com>,
	"Mujinsheng (DxJanesir)" <mujinsheng@huawei.com>,
	"chenjianfei (D)" <chenjianfei3@huawei.com>,
	"Fangyi (Eric)" <eric.fangyi@huawei.com>,
	"lishan (E)" <lishan24@huawei.com>,
	Renxuming <renxuming@huawei.com>,
	suxiaodong <suxiaodong1@huawei.com>,
	"caijunjie (A)" <caijunjie15@h-partners.com>,
	"zoudongjie (A)" <zoudongjie@huawei.com>
Subject: [Question Consultation] KVM: x86: No lock protection was applied in handle_ept_misconfig of kernel 5.10?
Date: Wed, 9 Jul 2025 06:32:10 +0000	[thread overview]
Message-ID: <fb4c14aa629a4dddb44d0fa9c4f7b498@huawei.com> (raw)

Hi all,

I noticed that in handle_ept_misconfig(), kvm_io_bus_write() is called. And within kvm_io_bus_write(), BUS is obtained
through srcu_dereference(). During this process, kvm->slots_lock is not acquired, nor is srcu_read_lock() called for 
protection. If another process is synchronizing BUS at the same time, synchronize_srcu_expedited() cannot safely reclaim
space(it cannot protect srcu_dereference() outside the critical section?), how can we ensure that BUS obtained by
kvm_io_bus_write() is the latest?

Thanks,
Junjie Cai

Reported by: Junjie Cai <caijunjie15@h-partners.com>

             reply	other threads:[~2025-07-09  6:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-09  6:32 zoudongjie (A) [this message]
2025-07-09 12:42 ` [Question Consultation] KVM: x86: No lock protection was applied in handle_ept_misconfig of kernel 5.10? Sean Christopherson

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