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([2001:b07:add:ec09:c399:bc87:7b6c:fb2a]) by smtp.googlemail.com with ESMTPSA id l7-20020a5d5607000000b0020c5253d904sm13941681wrv.80.2022.05.10.06.50.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 May 2022 06:51:06 -0700 (PDT) Message-ID: <8f24d358-1fbd-4598-1f2d-959b4f8d75fd@redhat.com> Date: Tue, 10 May 2022 15:50:57 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [syzbot] INFO: task hung in synchronize_rcu (3) Content-Language: en-US To: Sean Christopherson , syzbot Cc: akpm@linux-foundation.org, davem@davemloft.net, jhs@mojatatu.com, jiri@resnulli.us, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@elte.hu, mlevitsk@redhat.com, netdev@vger.kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, vinicius.gomes@intel.com, viro@zeniv.linux.org.uk, xiyou.wangcong@gmail.com References: <000000000000402c5305ab0bd2a2@google.com> <0000000000004f3c0d05dea46dac@google.com> From: Paolo Bonzini In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/10/22 15:45, Sean Christopherson wrote: >> >> KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io() >> >> bisection log:https://syzkaller.appspot.com/x/bisect.txt?x=16dc2e49f00000 >> start commit: ea4424be1688 Merge tag 'mtd/fixes-for-5.17-rc8' of git://g.. >> git tree: upstream >> kernel config:https://syzkaller.appspot.com/x/.config?x=442f8ac61e60a75e >> dashboard link:https://syzkaller.appspot.com/bug?extid=0c6da80218456f1edc36 >> syz repro:https://syzkaller.appspot.com/x/repro.syz?x=1685af9e700000 >> C reproducer:https://syzkaller.appspot.com/x/repro.c?x=11b09df1700000 >> >> If the result looks correct, please mark the issue as fixed by replying with: >> >> #syz fix: KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io() >> >> For information about bisection process see:https://goo.gl/tpsmEJ#bisection > #syz fix: KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io() > Are you sure? The hang is in synchronize_*rcu* and the testcase is unrelated to KVM. It seems like the testcase is not 100% reproducible. Paolo