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From: Wanpeng Li <kernellwp@gmail.com>
Date: Sun, 17 Dec 2017 18:37:02 +0800
Message-ID: <CANRm+CyW0B9jdMVusuZT45JA6H2fHfHDU2Zzvaw8UR66BrVyng@mail.gmail.com>
Subject: Re: BUG: unable to handle kernel NULL pointer dereference in irq_bypass_register_consumer
To: syzbot 
        <bot+dcff49641d63583853a5806197d79145931ac740@syzkaller.appspotmail.com>
Cc: kvm <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>, Radim Krcmar <rkrcmar@redhat.com>,
        syzkaller-bugs@googlegroups.com
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Sender: linux-kernel-owner@vger.kernel.org
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Lines: 93

2017-12-17 17:56 GMT+08:00 syzbot
<bot+dcff49641d63583853a5806197d79145931ac740@syzkaller.appspotmail.com>:
> Hello,
>
> syzkaller hit the following crash on
> 41d8c16909ebda40f7b4982a7f5e2ad102705ade
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
>
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers
>
>

I will have a look.

Regards,
Wanpeng Li

> BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
> IP: irq_bypass_register_consumer+0xbe/0x200 virt/lib/irqbypass.c:198
> PGD 20d26c067 P4D 20d26c067 PUD 20d26f067 PMD 0
> Oops: 0000 [#1] SMP
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Modules linked in:
> CPU: 1 PID: 8627 Comm: syz-executor7 Not tainted 4.15.0-rc3-next-20171213+
> #66
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:irq_bypass_register_consumer+0xbe/0x200 virt/lib/irqbypass.c:198
> RSP: 0018:ffffc9000691fd50 EFLAGS: 00010293
> RAX: ffff88021431e2c0 RBX: 0000000000000000 RCX: ffffffff825a774e
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc9000691fd70 R08: ffffffff825a7710 R09: 0000000000000004
> R10: ffffc9000691fd40 R11: 0000000000000004 R12: ffff88020d3d5368
> R13: ffff88020ef7c980 R14: ffff88020eef2768 R15: ffff88020d370000
> FS:  00007f2d09cf8700(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000010 CR3: 00000002143f1000 CR4: 00000000001426e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:417 [inline]
>  kvm_irqfd+0x6d4/0x860 arch/x86/kvm/../../../virt/kvm/eventfd.c:572
>  kvm_vm_ioctl+0x3e2/0x9f0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3000
>  vfs_ioctl fs/ioctl.c:46 [inline]
>  do_vfs_ioctl+0xaf/0x840 fs/ioctl.c:686
>  SYSC_ioctl fs/ioctl.c:701 [inline]
>  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
>  entry_SYSCALL_64_fastpath+0x1f/0x96
> RIP: 0033:0x452a39
> RSP: 002b:00007f2d09cf7c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452a39
> RDX: 0000000020080fe0 RSI: 000000004020ae76 RDI: 0000000000000003
> RBP: 0000000000000562 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f61d0
> R13: 00000000ffffffff R14: 00007f2d09cf86d4 R15: 0000000000000000
> Code: d1 fe 4d 8b 6c 24 10 4d 39 6e 10 74 2f 4d 39 f4 74 2a 4c 89 f3 e8 33
> 2c d1 fe 48 8b 1b 48 81 fb 60 e1 19 83 74 43 e8 22 2c d1 fe <4c> 39 6b 10 0f
> 94 c2 49 39 dc 0f 94 c0 08 c2 74 d9 e8 0c 2c d1
> RIP: irq_bypass_register_consumer+0xbe/0x200 virt/lib/irqbypass.c:198 RSP:
> ffffc9000691fd50
> CR2: 0000000000000010
> ---[ end trace 28b4667ba051ea9a ]---
> Kernel panic - not syncing: Fatal exception
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
>
>
> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzkaller@googlegroups.com.
> Please credit me with: Reported-by: syzbot <syzkaller@googlegroups.com>
>
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> Once a fix for this bug is merged into any tree, reply to this email with:
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