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Thu, 19 Mar 2020 08:14:59 -0700 (PDT) Received: from [192.168.178.58] ([151.21.15.43]) by smtp.gmail.com with ESMTPSA id y10sm3539341wma.9.2020.03.19.08.14.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 19 Mar 2020 08:14:58 -0700 (PDT) Subject: Re: WARNING in vcpu_enter_guest To: Sean Christopherson , syzbot Cc: bp@alien8.de, hpa@zytor.com, jmattson@google.com, joro@8bytes.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, rkrcmar@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, vkuznets@redhat.com, wanpengli@tencent.com, x86@kernel.org References: <000000000000f965b8059877e5e6@google.com> <00000000000081861f05a132b9cd@google.com> <20200319144952.GB11305@linux.intel.com> From: Paolo Bonzini Message-ID: <20be9560-fce7-1495-3a83-e2b56dbc2389@redhat.com> Date: Thu, 19 Mar 2020 16:14:55 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200319144952.GB11305@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/03/20 15:49, Sean Christopherson wrote: > On Thu, Mar 19, 2020 at 03:35:16AM -0700, syzbot wrote: >> syzbot has found a reproducer for the following crash on: >> >> HEAD commit: 5076190d mm: slub: be more careful about the double cmpxch.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=143ca61de00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=9f894bd92023de02 >> dashboard link: https://syzkaller.appspot.com/bug?extid=00be5da1d75f1cc95f6b >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10bb4023e00000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+00be5da1d75f1cc95f6b@syzkaller.appspotmail.com > Reproduced with a little tweaking of the reproducer, debug in progress. > I think the WARN_ON at x86.c:2447 is just bogus. You can always get it to trigger if garbage is passed to KVM_SET_CLOCK. Paolo