Syzkaller hit 'memory leak in ipv6_renew_options' bug.

2022/05/04 07:08:16 executed programs: 81
2022/05/04 07:08:27 executed programs: 95
2022/05/04 07:08:38 executed programs: 110
2022/05/04 07:08:47 executed programs: 129
BUG: memory leak
unreferenced object 0xffff88802185db80 (size 96):
  comm "syz-executor.2", pid 4338, jiffies 4295154437 (age 23.230s)
  hex dump (first 32 bytes):
    01 00 00 00 48 00 00 00 00 00 08 00 00 00 00 00  ....H...........
    00 00 00 00 00 00 00 00 c0 db 85 21 80 88 ff ff  ...........!....
  backtrace:
    [<00000000f45f5dcf>] sock_kmalloc+0xb5/0x100
    [<0000000026ce6694>] ipv6_renew_options+0x275/0x940
    [<0000000080436550>] do_ipv6_setsockopt.constprop.0+0x975/0x4570
    [<000000004e672bd1>] ipv6_setsockopt+0xd6/0x190
    [<000000003ec3ef1c>] tcp_setsockopt+0x139/0x26d0
    [<00000000e45fde51>] __sys_setsockopt+0x180/0x2a0
    [<00000000e2a0396c>] __x64_sys_setsockopt+0xba/0x150
    [<00000000354a1682>] do_syscall_64+0x3b/0x90
    [<00000000492b9cab>] entry_SYSCALL_64_after_hwframe+0x44/0xae



Syzkaller reproducer:
# {Threaded:true Collide:true Repeat:true RepeatTimes:0 Procs:8 Slowdown:1 Sandbox:none Leak:true NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true UseTmpDir:true HandleSegv:true Repro:false Trace:false LegacyOptions:{Fault:false FaultCall:0 FaultNth:0}}
r0 = socket$inet6(0xa, 0x1, 0x0)
setsockopt$inet6_tcp_TCP_REPAIR(r0, 0x6, 0x13, &(0x7f00000001c0)=0x1, 0x4)
connect$inet6(r0, &(0x7f0000000080)={0xa, 0x0, 0x0, @ipv4={'\x00', '\xff\xff', @empty}}, 0x1c)
setsockopt$inet6_IPV6_RTHDRDSTOPTS(r0, 0x29, 0x37, &(0x7f0000001780), 0x8)
setsockopt$inet6_IPV6_ADDRFORM(r0, 0x29, 0x1, &(0x7f0000000140), 0x4)
syncfs(0xffffffffffffffff)
ioctl$FS_IOC_GET_ENCRYPTION_POLICY(0xffffffffffffffff, 0x400c6615, &(0x7f0000000000)={0x0, @aes128, 0x0, @desc3})