memory leak in sctp_stream_init

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    e31736d9 Merge tag 'nios2-v5.5-rc2' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=126a177ee00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bbf3a35184a3ed64
dashboard link: https://syzkaller.appspot.com/bug?extid=772d9e36c490b18d51d1
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15602ddee00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12798251e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+772d9e36c490b18d51d1@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff8881080a3000 (size 4096):
  comm "syz-executor474", pid 7155, jiffies 4294942658 (age 15.870s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000df094087>] genradix_alloc_node lib/generic-radix-tree.c:90  
[inline]
    [<00000000df094087>] __genradix_ptr_alloc+0xf5/0x250  
lib/generic-radix-tree.c:122
    [<0000000057cfa7bb>] __genradix_prealloc+0x46/0x70  
lib/generic-radix-tree.c:223
    [<0000000029d02dac>] sctp_stream_alloc_out.part.0+0x57/0x80  
net/sctp/stream.c:86
    [<00000000bb930a04>] sctp_stream_alloc_out net/sctp/stream.c:151  
[inline]
    [<00000000bb930a04>] sctp_stream_init+0x129/0x180 net/sctp/stream.c:129
    [<00000000ba13c246>] sctp_association_init net/sctp/associola.c:229  
[inline]
    [<00000000ba13c246>] sctp_association_new+0x46e/0x700  
net/sctp/associola.c:295
    [<000000008eb57b4d>] sctp_connect_new_asoc+0x90/0x220  
net/sctp/socket.c:1070
    [<00000000ea24e048>] __sctp_connect+0x182/0x3b0 net/sctp/socket.c:1176
    [<00000000aa2c530a>] __sctp_setsockopt_connectx+0xa9/0xf0  
net/sctp/socket.c:1322
    [<0000000018934bfd>] sctp_getsockopt_connectx3 net/sctp/socket.c:1407  
[inline]
    [<0000000018934bfd>] sctp_getsockopt net/sctp/socket.c:8079 [inline]
    [<0000000018934bfd>] sctp_getsockopt+0x1394/0x32f6  
net/sctp/socket.c:8010
    [<000000005fd7e3c8>] sock_common_getsockopt+0x38/0x50  
net/core/sock.c:3108
    [<00000000333baf72>] __sys_getsockopt+0xa8/0x180 net/socket.c:2162
    [<00000000de0f98e4>] __do_sys_getsockopt net/socket.c:2177 [inline]
    [<00000000de0f98e4>] __se_sys_getsockopt net/socket.c:2174 [inline]
    [<00000000de0f98e4>] __x64_sys_getsockopt+0x26/0x30 net/socket.c:2174
    [<00000000cf1dfee9>] do_syscall_64+0x73/0x220  
arch/x86/entry/common.c:294
    [<000000000f416860>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



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