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BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x366/0x2520 lib/iov_iter.c:186
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_ubuf include/linux/iov_iter.h:29 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
 iterate_and_advance include/linux/iov_iter.h:271 [inline]
 _copy_to_iter+0x366/0x2520 lib/iov_iter.c:186
 copy_to_iter include/linux/uio.h:197 [inline]
 simple_copy_to_iter+0x68/0xa0 net/core/datagram.c:532
 __skb_datagram_iter+0x123/0xdc0 net/core/datagram.c:420
 skb_copy_datagram_iter+0x5c/0x200 net/core/datagram.c:546
 tun_put_user drivers/net/tun.c:2171 [inline]
 tun_do_read+0x2167/0x2ae0 drivers/net/tun.c:2250
 tun_chr_read_iter+0x3f0/0x670 drivers/net/tun.c:2274
 call_read_iter include/linux/fs.h:2081 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0xd67/0xeb0 fs/read_write.c:476
 ksys_read+0x20f/0x4c0 fs/read_write.c:619
 __do_sys_read fs/read_write.c:629 [inline]
 __se_sys_read fs/read_write.c:627 [inline]
 __x64_sys_read+0x93/0xd0 fs/read_write.c:627
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3819 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc_node+0x5cb/0xbc0 mm/slub.c:3903
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560
 __alloc_skb+0x352/0x790 net/core/skbuff.c:651
 alloc_skb include/linux/skbuff.h:1296 [inline]
 alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6394
 sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2783
 sock_alloc_send_skb include/net/sock.h:1855 [inline]
 __ip_append_data+0x4cc0/0x69c0 net/ipv4/ip_output.c:1122
 ip_make_skb+0x1ce/0x610 net/ipv4/ip_output.c:1558
 udp_sendmsg+0x2dad/0x31f0 net/ipv4/udp.c:1245
 udpv6_sendmsg+0x151a/0x3fb0 net/ipv6/udp.c:1390
 inet6_sendmsg+0x105/0x190 net/ipv6/af_inet6.c:660
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
 __sys_sendmmsg+0x3c4/0x950 net/socket.c:2724
 __do_sys_sendmmsg net/socket.c:2753 [inline]
 __se_sys_sendmmsg net/socket.c:2750 [inline]
 __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2750
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Bytes 38-41 of 92 are uninitialized
Memory access of size 92 starts at ffff88807bf39700
Data copied to user address 00007fda8edfecb0

CPU: 0 PID: 18904 Comm: syz-executor.0 Not tainted 6.8.0-rc6-syzkaller-00120-g87adedeba51a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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