[Devel] [PATCH] fuse kio: Replenish netaddr_cmp() with unix sockets type

[Alexey Kuznetsov]

Hello!

Do we have crash dump for this bug?

I was puzzled why we do not hit it in user space
and after some thinking decided it is really impossible
to have unix socket here.



On Fri, Oct 12, 2018 at 11:21 PM Alexey Kuznetsov <kuznet at virtuozzo.com> wrote:
>
> Hello!
>
> Fine. But I cannot figure out why we never hit this problem in user space,
> it does exactly the same thing.
>
> Also, add PCS_ADDRTYPE_RDMA just to be on safe side.
> On Fri, Oct 12, 2018 at 4:58 PM Kirill Tkhai <ktkhai at virtuozzo.com> wrote:
> >
> > We met crash in unix socket comparison:
> >
> > [21519.571700] kernel BUG at fs/fuse/kio/pcs/pcs_cs.c:170!
> > [21519.592534] RIP: 0010:[<ffffffffc080d4b0>]  [<ffffffffc080d4b0>] pcs_cs_find_create+0x300/0x310 [fuse_kio_pcs]
> > [21519.593817] RSP: 0018:ffff8af1f86f3d18  EFLAGS: 00010293
> > [21519.595102] RAX: 0000000000000000 RBX: ffff8af1d5369680 RCX: 0000000000000000
> > [21519.596429] RDX: 0000000000000001 RSI: ffff8af1d5369668 RDI: ffff8af234463820
> > [21519.597763] RBP: ffff8af1f86f3d58 R08: 0000000000000000 R09: 0000000000000000
> > [21519.599115] R10: ffff8af33fc07340 R11: 0000000000000001 R12: ffff8af1d5369668
> > [21519.600467] R13: ffff8af9e8758080 R14: ffff8af1d53696c0 R15: ffff8af234463800
> > [21519.602085] FS:  0000000000000000(0000) GS:ffff8afa1fac0000(0000) knlGS:0000000000000000
> > [21519.603509] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [21519.604918] CR2: 000000c4201db000 CR3: 000000104e744000 CR4: 00000000003607e0
> > [21519.606371] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [21519.607805] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > [21519.609604] Call Trace:
> > [21519.611106]  [<ffffffffc0806b50>] cslist_alloc+0x1f0/0x400 [fuse_kio_pcs]
> > [21519.612567]  [<ffffffffc08070ef>] pcs_map_complete+0x38f/0x420 [fuse_kio_pcs]
> > [21519.614001]  [<ffffffffc07fca59>] fuse_complete_map_work+0x79/0xc0 [fuse_kio_pcs]
> > [21519.615388]  [<ffffffff96cb7532>] process_one_work+0x182/0x440
> > [21519.616772]  [<ffffffff96cb86e6>] worker_thread+0x126/0x3c0
> > [21519.618270]  [<ffffffff96cb85c0>] ? manage_workers.isra.24+0x2a0/0x2a0
> > [21519.619703]  [<ffffffff96cbf681>] kthread+0xd1/0xe0
> > [21519.621134]  [<ffffffff96cbf5b0>] ? create_kthread+0x60/0x60
> > [21519.622507]  [<ffffffff97354677>] ret_from_fork_nospec_begin+0x21/0x21
> > [21519.623845]  [<ffffffff96cbf5b0>] ? create_kthread+0x60/0x60
> >
> > Extend netaddr_cmp() with PCS_ADDRTYPE_UNIX to make function
> > not to wonder unknown socket type. Note, unix sockets do not
> > care about address, since all of them are on local machine,
> > there is only port has a sense.
> >
> > https://pmc.acronis.com/browse/VSTOR-16083
> >
> > Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> > ---
> >  fs/fuse/kio/pcs/pcs_cs.c |    5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/fuse/kio/pcs/pcs_cs.c b/fs/fuse/kio/pcs/pcs_cs.c
> > index 56ab3adb36db..3f34c197850f 100644
> > --- a/fs/fuse/kio/pcs/pcs_cs.c
> > +++ b/fs/fuse/kio/pcs/pcs_cs.c
> > @@ -166,6 +166,8 @@ static inline int netaddr_cmp(PCS_NET_ADDR_T const *addr1, PCS_NET_ADDR_T const
> >         case PCS_ADDRTYPE_IP6:
> >                 sz = sizeof(struct in6_addr);
> >                 break;
> > +       case PCS_ADDRTYPE_UNIX:
> > +               return 0;
> >         default:
> >                 BUG();
> >         }
> > @@ -173,7 +175,8 @@ static inline int netaddr_cmp(PCS_NET_ADDR_T const *addr1, PCS_NET_ADDR_T const
> >         return memcmp(addr1->address, addr2->address, sz);
> >  }
> >
> > -int pcs_netaddr_cmp(PCS_NET_ADDR_T const *addr1, PCS_NET_ADDR_T const *addr2)
> > +static int pcs_netaddr_cmp(PCS_NET_ADDR_T const *addr1,
> > +                          PCS_NET_ADDR_T const *addr2)
> >  {
> >         return netaddr_cmp(addr1, addr2, 0);
> >  }
> >