4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: WANG Cong <xiyou.wangcong@xxxxxxxxx> [ Upstream commit 15e668070a64bb97f102ad9cf3bccbca0545cda8 ] Andrey reported the following kernel crash: kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 14446 Comm: syz-executor6 Not tainted 4.10.0+ #82 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88001f311700 task.stack: ffff88001f6e8000 RIP: 0010:ip6mr_sk_done+0x15a/0x3d0 net/ipv6/ip6mr.c:1618 RSP: 0018:ffff88001f6ef418 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 1ffff10003edde8c RCX: ffffc900043ee000 RDX: 0000000000000004 RSI: ffffffff83e3b3f8 RDI: 0000000000000020 RBP: ffff88001f6ef508 R08: fffffbfff0dcc5d8 R09: 0000000000000000 R10: ffffffff86e62ec0 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88001f6ef4e0 R15: ffff8800380a0040 FS: 00007f7a52cec700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000061c500 CR3: 000000001f1ae000 CR4: 00000000000006f0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rawv6_close+0x4c/0x80 net/ipv6/raw.c:1217 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432 sock_release+0x8d/0x1e0 net/socket.c:597 __sock_create+0x39d/0x880 net/socket.c:1226 sock_create_kern+0x3f/0x50 net/socket.c:1243 inet_ctl_sock_create+0xbb/0x280 net/ipv4/af_inet.c:1526 icmpv6_sk_init+0x163/0x500 net/ipv6/icmp.c:954 ops_init+0x10a/0x550 net/core/net_namespace.c:115 setup_net+0x261/0x660 net/core/net_namespace.c:291 copy_net_ns+0x27e/0x540 net/core/net_namespace.c:396 9pnet_virtio: no channels available for device ./file1 create_new_namespaces+0x437/0x9b0 kernel/nsproxy.c:106 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:205 SYSC_unshare kernel/fork.c:2281 [inline] SyS_unshare+0x64e/0x1000 kernel/fork.c:2231 entry_SYSCALL_64_fastpath+0x1f/0xc2 This is because net->ipv6.mr6_tables is not initialized at that point, ip6mr_rules_init() is not called yet, therefore on the error path when we iterator the list, we trigger this oops. Fix this by reordering ip6mr_rules_init() before icmpv6_sk_init(). Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/af_inet6.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -893,12 +893,12 @@ static int __init inet6_init(void) err = register_pernet_subsys(&inet6_net_ops); if (err) goto register_pernet_fail; - err = icmpv6_init(); - if (err) - goto icmp_fail; err = ip6_mr_init(); if (err) goto ipmr_fail; + err = icmpv6_init(); + if (err) + goto icmp_fail; err = ndisc_init(); if (err) goto ndisc_fail; @@ -1016,10 +1016,10 @@ igmp_fail: ndisc_cleanup(); ndisc_fail: ip6_mr_cleanup(); -ipmr_fail: - icmpv6_cleanup(); icmp_fail: unregister_pernet_subsys(&inet6_net_ops); +ipmr_fail: + icmpv6_cleanup(); register_pernet_fail: sock_unregister(PF_INET6); rtnl_unregister_all(PF_INET6);