On Sun, Dec 17, 2017 at 06:37:02PM +0800, Wanpeng Li wrote: > 2017-12-17 17:56 GMT+08:00 syzbot > <bot+dcff49641d63583853a5806197d79145931ac740@xxxxxxxxxxxxxxxxxxxxxxxxx>: > > 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.. syzbot is no longer reporting this crash. It seems it was reported during the time that KASAN was accidentally disabled in the syzbot config due to a change to the kconfig menus in linux-next. So it's probably the same as this one (which is still happening): #syz dup: KASAN: use-after-free Write in irq_bypass_register_consumer
