general protection fault in nldev_stat_set_doit

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 39f3b41a net: genetlink: return the error code when attrib..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=161be265e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3b8906eb6a7d6028
dashboard link: https://syzkaller.appspot.com/bug?extid=bd4af81bc51ee0283445
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=167103ede00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1710c265e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+bd4af8...@syzkaller.appspotmail.com

iwpm_register_pid: Unable to send a nlmsg (client = 2)
infiniband syz1: RDMA CMA: cma_listen_on_dev, error -98
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 9754 Comm: syz-executor069 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:nla_get_u32 include/net/netlink.h:1474 [inline]
RIP: 0010:nldev_stat_set_doit+0x63c/0xb70 drivers/infiniband/core/nldev.c:1760
Code: fc 01 0f 84 58 03 00 00 e8 41 83 bf fb 4c 8b a3 58 fd ff ff 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 04 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 6d
RSP: 0018:ffffc900068bf350 EFLAGS: 00010247
RAX: dffffc0000000000 RBX: ffffc900068bf728 RCX: ffffffff85b60470
RDX: 0000000000000000 RSI: ffffffff85b6047f RDI: 0000000000000004
RBP: ffffc900068bf750 R08: ffff88808c3ee140 R09: ffff8880a25e6010
R10: ffffed10144bcddc R11: ffff8880a25e6ee3 R12: 0000000000000000
R13: ffff88809acb0000 R14: ffff888092a42c80 R15: 000000009ef2e29a
FS: 0000000001ff0880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4733e34000 CR3: 00000000a9b27000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x5d9/0x980 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:672
____sys_sendmsg+0x753/0x880 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0x105/0x1d0 net/socket.c:2430
__do_sys_sendmsg net/socket.c:2439 [inline]
__se_sys_sendmsg net/socket.c:2437 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4403d9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc0efbc5c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004403d9
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000008 R09: 00000000004002c8
R10: 000000000000004a R11: 0000000000000246 R12: 0000000000401c60
R13: 0000000000401cf0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 548745c787596b79 ]---
RIP: 0010:nla_get_u32 include/net/netlink.h:1474 [inline]
RIP: 0010:nldev_stat_set_doit+0x63c/0xb70 drivers/infiniband/core/nldev.c:1760
Code: fc 01 0f 84 58 03 00 00 e8 41 83 bf fb 4c 8b a3 58 fd ff ff 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 04 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 6d
RSP: 0018:ffffc900068bf350 EFLAGS: 00010247
RAX: dffffc0000000000 RBX: ffffc900068bf728 RCX: ffffffff85b60470
RDX: 0000000000000000 RSI: ffffffff85b6047f RDI: 0000000000000004
RBP: ffffc900068bf750 R08: ffff88808c3ee140 R09: ffff8880a25e6010
R10: ffffed10144bcddc R11: ffff8880a25e6ee3 R12: 0000000000000000
R13: ffff88809acb0000 R14: ffff888092a42c80 R15: 000000009ef2e29a
FS: 0000000001ff0880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4733e34000 CR3: 00000000a9b27000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[Mark Zhang]

This issue happens when an "allocate a dynamic counter for a QP" netlink
command is received, while qpn (tb[RDMA_NLDEV_ATTR_RES_LQPN]) is not
available. Though the rdma command always set it, kernel should not
assume that input is correct.

Will fix it, thank you.