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BUG: KMSAN: uninit-value in slab_alloc_node mm/slub.c:2738 [inline]
BUG: KMSAN: uninit-value in slab_alloc mm/slub.c:2761 [inline]
BUG: KMSAN: uninit-value in __kmalloc_track_caller+0x531/0xc80 mm/slub.c:4365
CPU: 1 PID: 12767 Comm: syz-executor5 Not tainted 4.17.0+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1125
 __msan_warning_32+0x70/0xc0 mm/kmsan/kmsan_instr.c:620
 slab_alloc_node mm/slub.c:2738 [inline]
 slab_alloc mm/slub.c:2761 [inline]
 __kmalloc_track_caller+0x531/0xc80 mm/slub.c:4365
 kmemdup+0x95/0x140 mm/util.c:118
 neigh_sysctl_register+0xbe/0xd60 net/core/neighbour.c:3180
 addrconf_sysctl_register+0x159/0x370 net/ipv6/addrconf.c:6511
 ipv6_add_dev+0x1b49/0x1ee0 net/ipv6/addrconf.c:448
 addrconf_notify+0x420/0x5930 net/ipv6/addrconf.c:3406
 notifier_call_chain kernel/notifier.c:93 [inline]
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x13e/0x240 kernel/notifier.c:401
 call_netdevice_notifiers_info net/core/dev.c:1734 [inline]
 call_netdevice_notifiers net/core/dev.c:1752 [inline]
 register_netdevice+0x2178/0x2720 net/core/dev.c:7990
 register_netdev+0x93/0xd0 net/core/dev.c:8076
 sit_init_net+0x3e0/0xa90 net/ipv6/sit.c:1858
 ops_init+0x5b6/0x770 net/core/net_namespace.c:128
 setup_net+0x273/0xfa0 net/core/net_namespace.c:313
 copy_net_ns+0x464/0x8c0 net/core/net_namespace.c:436
 create_new_namespaces+0x7f5/0xe80 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0x23b/0x320 kernel/nsproxy.c:206
 ksys_unshare+0x889/0x10f0 kernel/fork.c:2409
 __do_sys_unshare kernel/fork.c:2477 [inline]
 __se_sys_unshare kernel/fork.c:2475 [inline]
 __x64_sys_unshare+0x59/0x80 kernel/fork.c:2475
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455b29
RSP: 002b:00007fcd179bcc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fcd179bd6d4 RCX: 0000000000455b29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c2575 R14: 00000000004d3a08 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:282 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:192
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:318
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan.c:325
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2753 [inline]
 __kmalloc_node_track_caller+0xb35/0x11b0 mm/slub.c:4395
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cb/0x9e0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:988 [inline]
 alloc_skb_with_frags+0x1e6/0xb80 net/core/skbuff.c:5254
 sock_alloc_send_pskb+0xb56/0x11a0 net/core/sock.c:2088
 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2105
 mld_newpack+0x2af/0xd00 net/ipv6/mcast.c:1585
 add_grhead net/ipv6/mcast.c:1689 [inline]
 add_grec+0x1dd4/0x2280 net/ipv6/mcast.c:1820
 mld_send_cr net/ipv6/mcast.c:1946 [inline]
 mld_ifc_timer_expire+0x10af/0x15a0 net/ipv6/mcast.c:2451
 call_timer_fn+0x280/0x5d0 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers+0xd96/0x11b0 kernel/time/timer.c:1666
 run_timer_softirq+0x43/0x70 kernel/time/timer.c:1692
 __do_softirq+0x592/0x979 kernel/softirq.c:285
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