On Wed, Dec 6, 2017 at 1:50 PM, Dmitry Vyukov <dvyu...@google.com> wrote: > On Fri, Oct 27, 2017 at 11:18 PM, Cong Wang <xiyou.wangc...@gmail.com> wrote: >> On Thu, Oct 26, 2017 at 11:00 PM, Dmitry Vyukov <dvyu...@google.com> wrote: >>> On Thu, Oct 26, 2017 at 7:58 PM, Tejun Heo <t...@kernel.org> 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 >> >> Can you try the fix below? There is no C reproducer so I can't verify it. > > > Hi Cong, > > syzbot can now test proposed patches, see > https://github.com/google/syzkaller/blob/master/docs/syzbot.md#communication-with-syzbot > for details. Please give it a try. > >> diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c >> index af4e76ac88ff..7816f44c576a 100644 >> --- a/net/kcm/kcmsock.c >> +++ b/net/kcm/kcmsock.c >> @@ -1433,11 +1433,12 @@ static int kcm_attach(struct socket *sock, >> struct socket *csock, >> KCM_STATS_INCR(mux->stats.psock_attach); >> mux->psocks_cnt++; >> psock_now_avail(psock); >> - spin_unlock_bh(&mux->lock); >> >> /* Schedule RX work in case there are already bytes queued */ >> strp_check_rcv(&psock->strp); >> >> + spin_unlock_bh(&mux->lock); >> + >> return 0; >> }
Hi Cong, Was this ever merged? Is it still necessary?
