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AJvYcCUe03pXSQFgTfFFVdzRb9/al6IiJRipjc65y7tZ5gEsT7qwoMtN8qJy+jMPpXjSMeqfx6F0RWMdvQDUPYM=@vger.kernel.org X-Gm-Message-State: AOJu0Yzie8Ejdjf8UiGjwDeKCgWO3xNh+YLgXyJoK4aOj7WL6FGONGaJ yAfGjYoxb/8+5aPhuAZP2FTO6C8Zb+Pz1K9W5fqU8QmoQzJ/GyfBLkSbrvxVlpEriI3mJ7/RKcQ dc5oHqg== X-Received: from pfbea27.prod.google.com ([2002:a05:6a00:4c1b:b0:82c:ec3c:f2d0]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:f88:b0:829:803e:6798 with SMTP id d2e1a72fcca58-82d0dbea543mr625141b3a.56.1775168595062; Thu, 02 Apr 2026 15:23:15 -0700 (PDT) Date: Thu, 2 Apr 2026 15:23:13 -0700 In-Reply-To: <20260402064209.8ba7wrBI@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260329131543.91733-1-shaikhkamal2012@gmail.com> <20260330101814.7fa1e31e@gandalf.local.home> <20260402064209.8ba7wrBI@linutronix.de> Message-ID: Subject: Re: [PATCH] KVM: x86/xen: Fix sleeping lock in hard IRQ context on PREEMPT_RT From: Sean Christopherson To: Sebastian Andrzej Siewior Cc: David Woodhouse , "rostedt@goodmis.org" , "shaikhkamal2012@gmail.com" , "syzbot+919877893c9d28162dc2@syzkaller.appspotmail.com" , "me@brighamcampbell.com" , "linux-rt-devel@lists.linux.dev" , "hpa@zytor.com" , "linux-kernel@vger.kernel.org" , "paul@xen.org" , "kvm@vger.kernel.org" , "skhan@linuxfoundation.org" Content-Type: text/plain; charset="us-ascii" On Thu, Apr 02, 2026, Sebastian Andrzej Siewior wrote: > On 2026-04-01 08:40:07 [-0700], Sean Christopherson wrote: > > Re-reading through the thread where you proposed using trylock, and through > > commit bbe17c625d68 ("KVM: x86/xen: Fix potential deadlock in kvm_xen_update_runstate_guest()"), > > I think I agree with using trylock for "fast" paths. > > Has bbe17c625d68 been applied for PREEMPT_RT reasons? Ya, I think it was to suppress a PREEMPT_RT-only splat: https://lore.kernel.org/all/20240227115648.3104-8-dwmw2@infradead.org