syzbot


KASAN: use-after-free Read in irq_bypass_unregister_consumer

Status: closed as dup on 2018/05/26 09:22
Reported-by: syzbot+37364ced0d0b0fdf115c@syzkaller.appspotmail.com
First crash: 1546d, last: 1504d
Duplicate of (1):
Title Repro Cause bisect Fix bisect Count Last Reported
KASAN: use-after-free Write in irq_bypass_register_consumer C 1632 1487d 1748d

Sample crash report:
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
IPVS: ftp: loaded support on port[0] = 21
==================================================================
BUG: KASAN: use-after-free in irq_bypass_unregister_consumer+0x3cd/0x4a0 virt/lib/irqbypass.c:247
Read of size 8 at addr ffff8801adf2a168 by task kworker/0:1/24

CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.17.0-rc5+ #59
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kvm-irqfd-cleanup irqfd_shutdown
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 irq_bypass_unregister_consumer+0x3cd/0x4a0 virt/lib/irqbypass.c:247
 irqfd_shutdown+0x112/0x1a0 arch/x86/kvm/../../../virt/kvm/eventfd.c:145
 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

Allocated by task 4534:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620
 kmalloc include/linux/slab.h:512 [inline]
 kzalloc include/linux/slab.h:701 [inline]
 kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:296 [inline]
 kvm_irqfd+0x187/0x1ec0 arch/x86/kvm/../../../virt/kvm/eventfd.c:572
 kvm_vm_ioctl+0xf84/0x1d90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2997
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1cf/0x16a0 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 __do_sys_ioctl fs/ioctl.c:708 [inline]
 __se_sys_ioctl fs/ioctl.c:706 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 24:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xd9/0x260 mm/slab.c:3813
 irqfd_shutdown+0x13a/0x1a0 arch/x86/kvm/../../../virt/kvm/eventfd.c:148
 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

The buggy address belongs to the object at ffff8801adf2a000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 360 bytes inside of
 512-byte region [ffff8801adf2a000, ffff8801adf2a200)
The buggy address belongs to the page:
page:ffffea0006b7ca80 count:1 mapcount:0 mapping:ffff8801adf2a000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801adf2a000 0000000000000000 0000000100000006
raw: ffffea0007647a20 ffffea0006b45ba0 ffff8801da800940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801adf2a000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801adf2a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801adf2a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff8801adf2a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801adf2a200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2018/05/20 03:38 upstream 0b449a441dac f48c20b8 .config log report syz C
ci-upstream-kasan-gce-root 2018/07/01 11:54 upstream 883c9ab9eb59 dba0b50e .config log report