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[91.219.240.2]) by smtp.gmail.com with ESMTPSA id u4sm11888104edy.18.2020.08.10.01.06.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Aug 2020 01:06:29 -0700 (PDT) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, syzbot Cc: bp@alien8.de, hpa@zytor.com, jmattson@google.com, joro@8bytes.org, linux-kernel@vger.kernel.org, mingo@redhat.com, pbonzini@redhat.com, sean.j.christopherson@intel.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, wanpengli@tencent.com, x86@kernel.org, Nitesh Narayan Lal Subject: Re: WARNING in rcu_irq_exit In-Reply-To: <000000000000843c1005ac7a990c@google.com> References: <000000000000843c1005ac7a990c@google.com> Date: Mon, 10 Aug 2020 10:06:28 +0200 Message-ID: <875z9qorgb.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot writes: > Hello, > > syzbot found the following issue on: > > HEAD commit: 47ec5303 Merge git://git.kernel.org/pub/scm/linux/kernel/g.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17228c62900000 > kernel config: https://syzkaller.appspot.com/x/.config?x=e0c783f658542f35 > dashboard link: https://syzkaller.appspot.com/bug?extid=c116bcba868f8148cd3e > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+c116bcba868f8148cd3e@syzkaller.appspotmail.com > > device lo entered promiscuous mode > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 29030 at kernel/rcu/tree.c:772 rcu_irq_exit+0x19/0x20 kernel/rcu/tree.c:773 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 1 PID: 29030 Comm: syz-executor.2 Not tainted 5.8.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1f0/0x31e lib/dump_stack.c:118 > panic+0x264/0x7a0 kernel/panic.c:231 > __warn+0x227/0x250 kernel/panic.c:600 > report_bug+0x1b1/0x2e0 lib/bug.c:198 > handle_bug+0x42/0x80 arch/x86/kernel/traps.c:235 > exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:255 > asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536 > RIP: 0010:rcu_irq_exit+0x19/0x20 kernel/rcu/tree.c:773 > Code: 0b c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 83 3d fd fb 68 01 00 74 0b 65 8b 05 50 00 dc 77 85 c0 75 05 e9 07 ff ff ff <0f> 0b e9 00 ff ff ff 41 56 53 83 3d da fb 68 01 00 74 0f 65 8b 05 > RSP: 0018:ffffc90001806e70 EFLAGS: 00010002 > RAX: 0000000000000001 RBX: 0000000000000082 RCX: 0000000000040000 > RDX: ffffc9000da6b000 RSI: 0000000000003173 RDI: 0000000000003174 > RBP: ffff8880a2ce9fa8 R08: ffffffff817a9064 R09: ffffed1015d26cf5 > R10: ffffed1015d26cf5 R11: 0000000000000000 R12: dffffc0000000000 > R13: 000000000000003c R14: dffffc0000000000 R15: 000000000000003c > rcu_irq_exit_irqson+0x80/0x110 kernel/rcu/tree.c:827 ... Chances are this is fixed by Tglx' commit 87fa7f3e98a1310ef1ac1900e7ee7f9610a038bc Author: Thomas Gleixner Date: Wed Jul 8 21:51:54 2020 +0200 x86/kvm: Move context tracking where it belongs (in kvm/next currently). See also: https://lore.kernel.org/kvm/ece36eb1-253a-8ec6-c183-309c10bb35d5@redhat.com/ which was confirmed to be fixed by the above mentioned commit. -- Vitaly