linux-kernel - [PATCH 1/4] x86/irq: Ensure PI wakeup handler is unregistered before module unload

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri,  8 Oct 2021 17:11:04 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, Paolo Bonzini <pbonzini@...hat.com>
Cc:     "H. Peter Anvin" <hpa@...or.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Subject: [PATCH 1/4] x86/irq: Ensure PI wakeup handler is unregistered before
 module unload

Add a synchronize_rcu() after setting the posted interrupt wakeup handler
to ensure all readers, i.e. in-flight IRQ handlers, see the new handler
before returning to the caller.  If the caller is an exiting module and
is unregistering its handler, failure to wait could result in the IRQ
handler jumping into an unloaded module.

Fixes: f6b3c72c2366 ("x86/irq: Define a global vector for VT-d Posted-Interrupts")
Cc: stable@...r.kernel.org
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kernel/irq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index e28f6a5d14f1..20773d315308 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -293,6 +293,7 @@ void kvm_set_posted_intr_wakeup_handler(void (*handler)(void))
 		kvm_posted_intr_wakeup_handler = handler;
 	else
 		kvm_posted_intr_wakeup_handler = dummy_handler;
+	synchronize_rcu();
 }
 EXPORT_SYMBOL_GPL(kvm_set_posted_intr_wakeup_handler);
 
-- 
2.33.0.882.g93a45727a2-goog