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

[Kirill Tkhai]

Sadly, but we have no the crash dump

On 15.10.2018 16:39, Alexey Kuznetsov wrote:
> 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);
>>>  }
>>>