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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:30 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0xf0e/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_ubuf include/linux/iov_iter.h:30 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 _copy_to_iter+0xf0e/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 net/socket.c:1065 [inline]
 sock_recvmsg+0x23c/0x390 net/socket.c:1087
 sock_read_iter+0x2c8/0x360 net/socket.c:1157
 io_iter_do_read io_uring/rw.c:828 [inline]
 __io_read+0xbe9/0x24a0 io_uring/rw.c:941
 io_read+0x3e/0x100 io_uring/rw.c:1020
 __io_issue_sqe+0x2b8/0x790 io_uring/io_uring.c:1773
 io_issue_sqe+0xae/0x19b0 io_uring/io_uring.c:1796
 io_queue_sqe io_uring/io_uring.c:2025 [inline]
 io_req_task_submit+0xe5/0x1c0 io_uring/io_uring.c:1415
 io_poll_task_func+0x1166/0x17a0 io_uring/poll.c:352
 io_handle_tw_list+0x224/0x5d0 io_uring/io_uring.c:1102
 tctx_task_work_run+0xfc/0x3b0 io_uring/io_uring.c:1167
 tctx_task_work+0x6d/0xc0 io_uring/io_uring.c:1185
 task_work_run+0x206/0x2b0 kernel/task_work.c:227
 get_signal+0x139/0x2a20 kernel/signal.c:2807
 arch_do_signal_or_restart+0x53/0xbf0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0xec/0x330 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1e3/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4186 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 kmem_cache_alloc_node_noprof+0x818/0xf00 mm/slub.c:4281
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:578
 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:669
 alloc_skb include/linux/skbuff.h:1336 [inline]
 ipmr_cache_report+0x410/0x2200 net/ipv4/ipmr.c:1052
 ipmr_cache_unresolved+0x53d/0xd30 net/ipv4/ipmr.c:1152
 ip_mr_input+0xe78/0xfb0 net/ipv4/ipmr.c:2221
 dst_input include/net/dst.h:471 [inline]
 ip_rcv_finish+0x57a/0x5c0 net/ipv4/ip_input.c:454
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ip_rcv+0xcb/0x380 net/ipv4/ip_input.c:574
 __netif_receive_skb_one_core net/core/dev.c:5979 [inline]
 __netif_receive_skb+0x312/0xac0 net/core/dev.c:6092
 netif_receive_skb_internal net/core/dev.c:6178 [inline]
 netif_receive_skb+0x57/0x630 net/core/dev.c:6237
 tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485
 tun_get_user+0x5028/0x6ca0 drivers/net/tun.c:1950
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1996
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbdf/0x15d0 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746
 x64_sys_call+0x3014/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Bytes 22-27 of 28 are uninitialized
Memory access of size 28 starts at ffff888036a6b700
Data copied to user address 0000200000001800

CPU: 0 UID: 0 PID: 20388 Comm: syz.8.2663 Tainted: G        W           syzkaller #0 PREEMPT(none) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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