Re: KASAN: use-after-free Read in get_work_pool

[Dmitry Vyukov]

On Thu, Oct 26, 2017 at 7:58 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hello,
>
> On Thu, Oct 26, 2017 at 09:35:44AM -0700, syzbot wrote:
>> BUG: KASAN: use-after-free in __read_once_size
>> include/linux/compiler.h:276 [inline]
>> BUG: KASAN: use-after-free in atomic64_read
>> arch/x86/include/asm/atomic64_64.h:21 [inline]
>> BUG: KASAN: use-after-free in atomic_long_read
>> include/asm-generic/atomic-long.h:44 [inline]
>> BUG: KASAN: use-after-free in get_work_pool+0x1c2/0x1e0
>> kernel/workqueue.c:709
>> Read of size 8 at addr ffff8801cc58c378 by task syz-executor5/21326
>>
>> CPU: 1 PID: 21326 Comm: syz-executor5 Not tainted 4.13.0+ #43
>> Hardware name: Google Google Compute Engine/Google Compute Engine,
>> BIOS Google 01/01/2011
>> Call Trace:
>>  __dump_stack lib/dump_stack.c:16 [inline]
>>  dump_stack+0x194/0x257 lib/dump_stack.c:52
>>  print_address_description+0x73/0x250 mm/kasan/report.c:252
>>  kasan_report_error mm/kasan/report.c:351 [inline]
>>  kasan_report+0x24e/0x340 mm/kasan/report.c:409
>>  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
>>  __read_once_size include/linux/compiler.h:276 [inline]
>>  atomic64_read arch/x86/include/asm/atomic64_64.h:21 [inline]
>>  atomic_long_read include/asm-generic/atomic-long.h:44 [inline]
>>  get_work_pool+0x1c2/0x1e0 kernel/workqueue.c:709
>>  __queue_work+0x235/0x1150 kernel/workqueue.c:1401
>>  queue_work_on+0x16a/0x1c0 kernel/workqueue.c:1486
>>  queue_work include/linux/workqueue.h:489 [inline]
>>  strp_check_rcv+0x25/0x30 net/strparser/strparser.c:553
>>  kcm_attach net/kcm/kcmsock.c:1439 [inline]
>>  kcm_attach_ioctl net/kcm/kcmsock.c:1460 [inline]
>>  kcm_ioctl+0x826/0x1610 net/kcm/kcmsock.c:1695
>>  sock_do_ioctl+0x65/0xb0 net/socket.c:961
>>  sock_ioctl+0x2c2/0x440 net/socket.c:1058
>>  vfs_ioctl fs/ioctl.c:45 [inline]
>>  do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685
>>  SYSC_ioctl fs/ioctl.c:700 [inline]
>>  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
>>  entry_SYSCALL_64_fastpath+0x1f/0xbe
>
> Looks like kcm is trying to reuse a work item whose last workqueue has
> been destroyed without re-initing it.  A work item needs to be
> reinit'd.

+kcm maintainers

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