syz_tun: entered allmulticast mode
pimreg: entered allmulticast mode
=====================================================
BUG: KMSAN: kernel-infoleak-after-free in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak-after-free in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_iovec include/linux/iov_iter.h:52 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance include/linux/iov_iter.h:330 [inline]
BUG: KMSAN: kernel-infoleak-after-free in _copy_to_iter+0x4e4/0x33f0 lib/iov_iter.c:185
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_iovec include/linux/iov_iter.h:52 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
 iterate_and_advance include/linux/iov_iter.h:330 [inline]
 _copy_to_iter+0x4e4/0x33f0 lib/iov_iter.c:185
 copy_to_iter include/linux/uio.h:220 [inline]
 simple_copy_to_iter net/core/datagram.c:521 [inline]
 __skb_datagram_iter+0x196/0x12c0 net/core/datagram.c:402
 skb_copy_datagram_iter+0x5b/0x1e0 net/core/datagram.c:535
 skb_copy_datagram_msg include/linux/skbuff.h:4167 [inline]
 raw_recvmsg+0x2c8/0xab0 net/ipv4/raw.c:766
 inet_recvmsg+0x343/0x6a0 net/ipv4/af_inet.c:883
 sock_recvmsg_nosec+0x19d/0x2f0 net/socket.c:1065
 ____sys_recvmsg+0x4e5/0x610 net/socket.c:2832
 ___sys_recvmsg+0x20b/0x850 net/socket.c:2876
 do_recvmmsg+0x50b/0xdf0 net/socket.c:2963
 __sys_recvmmsg+0xf3/0x460 net/socket.c:3045
 __do_compat_sys_recvmmsg_time32 net/compat.c:418 [inline]
 __se_compat_sys_recvmmsg_time32 net/compat.c:414 [inline]
 __ia32_compat_sys_recvmmsg_time32+0x102/0x1b0 net/compat.c:414
 ia32_sys_call+0x2970/0x4310 arch/x86/include/generated/asm/syscalls_32.h:338
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb0/0x150 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_free_hook mm/slub.c:2348 [inline]
 slab_free mm/slub.c:4695 [inline]
 kmem_cache_free+0x2a1/0xec0 mm/slub.c:4797
 skb_kfree_head net/core/skbuff.c:1045 [inline]
 skb_free_head+0x13c/0x3a0 net/core/skbuff.c:1059
 skb_release_data+0x9f7/0xac0 net/core/skbuff.c:1086
 skb_release_all net/core/skbuff.c:1151 [inline]
 __kfree_skb+0x6b/0x260 net/core/skbuff.c:1165
 consume_skb+0x83/0x230 net/core/skbuff.c:1397
 netlink_broadcast_filtered+0x227b/0x2430 net/netlink/af_netlink.c:1537
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0x15b/0x2f0 net/netlink/af_netlink.c:2595
 rtnl_notify+0xba/0x100 net/core/rtnetlink.c:958
 inet_ifmcaddr_notify+0x171/0x300 net/ipv4/igmp.c:1495
 ____ip_mc_inc_group+0x94c/0x10d0 net/ipv4/igmp.c:1564
 __ip_mc_join_group+0x5dc/0x830 net/ipv4/igmp.c:2305
 ip_mc_join_group+0x38/0x50 net/ipv4/igmp.c:2315
 do_ip_setsockopt+0x3c8b/0x4a70 net/ipv4/ip_sockglue.c:1248
 ip_setsockopt+0x106/0x210 net/ipv4/ip_sockglue.c:1417
 raw_setsockopt+0x1b9/0x2f0 net/ipv4/raw.c:845
 sock_common_setsockopt+0xf2/0x140 net/core/sock.c:3903
 do_sock_setsockopt net/socket.c:2344 [inline]
 __sys_setsockopt+0x43e/0x580 net/socket.c:2369
 __do_sys_setsockopt net/socket.c:2375 [inline]
 __se_sys_setsockopt net/socket.c:2372 [inline]
 __ia32_sys_setsockopt+0xf3/0x1a0 net/socket.c:2372
 ia32_sys_call+0x24c2/0x4310 arch/x86/include/generated/asm/syscalls_32.h:367
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb0/0x150 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Bytes 22-27 of 28 are uninitialized
Memory access of size 28 starts at ffff888033a46100
Data copied to user address 0000000080000640

CPU: 1 UID: 0 PID: 20411 Comm: syz.0.4098 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
=====================================================