=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline]
BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:169 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x870/0x1fd0 lib/iov_iter.c:529
 instrument_copy_to_user include/linux/instrumented.h:121 [inline]
 copyout lib/iov_iter.c:169 [inline]
 _copy_to_iter+0x870/0x1fd0 lib/iov_iter.c:529
 copy_to_iter include/linux/uio.h:179 [inline]
 simple_copy_to_iter+0x68/0xa0 net/core/datagram.c:513
 __skb_datagram_iter+0x123/0xdc0 net/core/datagram.c:419
 skb_copy_datagram_iter+0x5c/0x200 net/core/datagram.c:527
 tun_put_user drivers/net/tun.c:2145 [inline]
 tun_do_read+0x24e8/0x2d90 drivers/net/tun.c:2224
 tun_chr_read_iter+0x3f0/0x670 drivers/net/tun.c:2248
 call_read_iter include/linux/fs.h:2183 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x8cd/0xf40 fs/read_write.c:470
 ksys_read+0x21f/0x4f0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x93/0xd0 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was stored to memory at:
 pskb_expand_head+0x328/0x19b0 net/core/skbuff.c:1907
 __skb_cow include/linux/skbuff.h:3537 [inline]
 skb_cow_head include/linux/skbuff.h:3571 [inline]
 ip_tunnel_xmit+0x3a7b/0x4220 net/ipv4/ip_tunnel.c:806
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 erspan_xmit+0x140f/0x2150 net/ipv4/ip_gre.c:715
 __netdev_start_xmit include/linux/netdevice.h:4863 [inline]
 netdev_start_xmit include/linux/netdevice.h:4877 [inline]
 xmit_one net/core/dev.c:3575 [inline]
 dev_hard_start_xmit+0x253/0xa20 net/core/dev.c:3591
 sch_direct_xmit+0x3f7/0xdc0 net/sched/sch_generic.c:342
 __dev_xmit_skb net/core/dev.c:3802 [inline]
 __dev_queue_xmit+0x3601/0x5ac0 net/core/dev.c:4207
 dev_queue_xmit include/linux/netdevice.h:3033 [inline]
 br_dev_queue_push_xmit+0x851/0x910 net/bridge/br_forward.c:53
 NF_HOOK include/linux/netfilter.h:302 [inline]
 br_forward_finish+0xfa/0x340 net/bridge/br_forward.c:66
 NF_HOOK include/linux/netfilter.h:302 [inline]
 __br_forward+0x8e6/0xaf0 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0x3dd/0x520 net/bridge/br_forward.c:189
 br_flood+0x61b/0x8f0 net/bridge/br_forward.c:231
 br_dev_xmit+0x1b79/0x1c20
 __netdev_start_xmit include/linux/netdevice.h:4863 [inline]
 netdev_start_xmit include/linux/netdevice.h:4877 [inline]
 xmit_one net/core/dev.c:3575 [inline]
 dev_hard_start_xmit+0x253/0xa20 net/core/dev.c:3591
 __dev_queue_xmit+0x3c7f/0x5ac0 net/core/dev.c:4241
 dev_queue_xmit include/linux/netdevice.h:3033 [inline]
 neigh_hh_output include/net/neighbour.h:530 [inline]
 neigh_output include/net/neighbour.h:544 [inline]
 ip_finish_output2+0x17a6/0x1a60 net/ipv4/ip_output.c:228
 __ip_finish_output+0x266/0x720
 ip_finish_output+0x4b/0x420 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip_output+0x215/0x500 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:444 [inline]
 ip_local_out+0xe9/0x140 net/ipv4/ip_output.c:126
 igmpv3_sendpack+0x2a6/0x5b0 net/ipv4/igmp.c:424
 igmpv3_send_cr net/ipv4/igmp.c:720 [inline]
 igmp_ifc_timer_expire+0x1410/0x1cc0 net/ipv4/igmp.c:810
 call_timer_fn+0x45/0x4e0 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x861/0xf90 kernel/time/timer.c:2022
 run_timer_softirq+0x68/0xe0 kernel/time/timer.c:2035
 __do_softirq+0x1c9/0x7c5 kernel/softirq.c:571

Uninit was stored to memory at:
 pskb_expand_head+0x328/0x19b0 net/core/skbuff.c:1907
 __skb_cow include/linux/skbuff.h:3537 [inline]
 skb_cow_head include/linux/skbuff.h:3571 [inline]
 erspan_xmit+0x862/0x2150 net/ipv4/ip_gre.c:688
 __netdev_start_xmit include/linux/netdevice.h:4863 [inline]
 netdev_start_xmit include/linux/netdevice.h:4877 [inline]
 xmit_one net/core/dev.c:3575 [inline]
 dev_hard_start_xmit+0x253/0xa20 net/core/dev.c:3591
 sch_direct_xmit+0x3f7/0xdc0 net/sched/sch_generic.c:342
 __dev_xmit_skb net/core/dev.c:3802 [inline]
 __dev_queue_xmit+0x3601/0x5ac0 net/core/dev.c:4207
 dev_queue_xmit include/linux/netdevice.h:3033 [inline]
 br_dev_queue_push_xmit+0x851/0x910 net/bridge/br_forward.c:53
 NF_HOOK include/linux/netfilter.h:302 [inline]
 br_forward_finish+0xfa/0x340 net/bridge/br_forward.c:66
 NF_HOOK include/linux/netfilter.h:302 [inline]
 __br_forward+0x8e6/0xaf0 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0x3dd/0x520 net/bridge/br_forward.c:189
 br_flood+0x61b/0x8f0 net/bridge/br_forward.c:231
 br_dev_xmit+0x1b79/0x1c20
 __netdev_start_xmit include/linux/netdevice.h:4863 [inline]
 netdev_start_xmit include/linux/netdevice.h:4877 [inline]
 xmit_one net/core/dev.c:3575 [inline]
 dev_hard_start_xmit+0x253/0xa20 net/core/dev.c:3591
 __dev_queue_xmit+0x3c7f/0x5ac0 net/core/dev.c:4241
 dev_queue_xmit include/linux/netdevice.h:3033 [inline]
 neigh_hh_output include/net/neighbour.h:530 [inline]
 neigh_output include/net/neighbour.h:544 [inline]
 ip_finish_output2+0x17a6/0x1a60 net/ipv4/ip_output.c:228
 __ip_finish_output+0x266/0x720
 ip_finish_output+0x4b/0x420 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip_output+0x215/0x500 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:444 [inline]
 ip_local_out+0xe9/0x140 net/ipv4/ip_output.c:126
 igmpv3_sendpack+0x2a6/0x5b0 net/ipv4/igmp.c:424
 igmpv3_send_cr net/ipv4/igmp.c:720 [inline]
 igmp_ifc_timer_expire+0x1410/0x1cc0 net/ipv4/igmp.c:810
 call_timer_fn+0x45/0x4e0 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x861/0xf90 kernel/time/timer.c:2022
 run_timer_softirq+0x68/0xe0 kernel/time/timer.c:2035
 __do_softirq+0x1c9/0x7c5 kernel/softirq.c:571

Uninit was created at:
 slab_post_alloc_hook+0x12d/0xb60 mm/slab.h:766
 slab_alloc_node mm/slub.c:3452 [inline]
 __kmem_cache_alloc_node+0x518/0x920 mm/slub.c:3491
 __do_kmalloc_node mm/slab_common.c:967 [inline]
 __kmalloc_node_track_caller+0x118/0x3c0 mm/slab_common.c:988
 kmalloc_reserve net/core/skbuff.c:492 [inline]
 __alloc_skb+0x3b8/0x900 net/core/skbuff.c:565
 alloc_skb include/linux/skbuff.h:1270 [inline]
 igmpv3_newpack+0x19f/0x14e0 net/ipv4/igmp.c:359
 add_grhead+0x83/0x430 net/ipv4/igmp.c:440
 add_grec+0x1eb6/0x20c0 net/ipv4/igmp.c:574
 igmpv3_send_cr net/ipv4/igmp.c:672 [inline]
 igmp_ifc_timer_expire+0x452/0x1cc0 net/ipv4/igmp.c:810
 call_timer_fn+0x45/0x4e0 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x861/0xf90 kernel/time/timer.c:2022
 run_timer_softirq+0x68/0xe0 kernel/time/timer.c:2035
 __do_softirq+0x1c9/0x7c5 kernel/softirq.c:571

Bytes 38-41 of 104 are uninitialized
Memory access of size 104 starts at ffff888043adc0c0
Data copied to user address 00007f28e5ecf980

CPU: 0 PID: 30729 Comm: syz-executor.1 Tainted: G        W          6.2.0-syzkaller-81152-g97e36f4aa06f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
=====================================================