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BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in _inline_copy_to_user include/linux/uaccess.h:205 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_user+0xcc/0x120 lib/usercopy.c:26
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 _inline_copy_to_user include/linux/uaccess.h:205 [inline]
 _copy_to_user+0xcc/0x120 lib/usercopy.c:26
 copy_to_user include/linux/uaccess.h:236 [inline]
 move_addr_to_user+0x29a/0x400 net/socket.c:306
 ____sys_recvmsg+0x232/0x610 net/socket.c:2819
 ___sys_recvmsg+0x20b/0x850 net/socket.c:2854
 do_recvmmsg+0x40e/0xdf0 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0x383/0x500 net/socket.c:3039
 x64_sys_call+0x365f/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 packet_recvmsg+0x1595/0x24e0 net/packet/af_packet.c:3517
 sock_recvmsg_nosec+0x240/0x2f0 net/socket.c:1078
 ____sys_recvmsg+0x4e5/0x610 net/socket.c:2810
 ___sys_recvmsg+0x20b/0x850 net/socket.c:2854
 do_recvmmsg+0x40e/0xdf0 net/socket.c:2949
 __sys_recvmmsg net/socket.c:3023 [inline]
 __do_sys_recvmmsg net/socket.c:3046 [inline]
 __se_sys_recvmmsg net/socket.c:3039 [inline]
 __x64_sys_recvmmsg+0x383/0x500 net/socket.c:3039
 x64_sys_call+0x365f/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 eth_header_parse+0xdb/0x160 net/ethernet/eth.c:204
 dev_parse_header include/linux/netdevice.h:3446 [inline]
 packet_rcv+0x1092/0x23a0 net/packet/af_packet.c:2186
 dev_queue_xmit_nit+0xfc3/0x1160 net/core/dev.c:2587
 xmit_one net/core/dev.c:3849 [inline]
 dev_hard_start_xmit+0x16b/0xa30 net/core/dev.c:3869
 sch_direct_xmit+0x3b2/0xcf0 net/sched/sch_generic.c:347
 __dev_xmit_skb net/core/dev.c:4169 [inline]
 __dev_queue_xmit+0x2724/0x58f0 net/core/dev.c:4783
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 __bpf_tx_skb net/core/filter.c:2153 [inline]
 __bpf_redirect_common net/core/filter.c:2197 [inline]
 __bpf_redirect+0x162d/0x1760 net/core/filter.c:2204
 ____bpf_clone_redirect net/core/filter.c:2487 [inline]
 bpf_clone_redirect+0x4b5/0x6d0 net/core/filter.c:2450
 ___bpf_prog_run+0x1297/0xeba0 kernel/bpf/core.c:2021
 __bpf_prog_run512+0xc5/0x100 kernel/bpf/core.c:2317
 bpf_dispatcher_nop_func include/linux/bpf.h:1376 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 bpf_test_run+0x496/0xe00 net/bpf/test_run.c:423
 bpf_prog_test_run_skb+0x2377/0x3200 net/bpf/test_run.c:1158
 bpf_prog_test_run+0x5c2/0xa40 kernel/bpf/syscall.c:4703
 __sys_bpf+0x873/0xeb0 kernel/bpf/syscall.c:6182
 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
 __x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:6272
 x64_sys_call+0x31c3/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4960 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586
 pskb_expand_head+0x1fc/0x15d0 net/core/skbuff.c:2282
 skb_ensure_writable+0x44e/0x510 net/core/skbuff.c:6314
 __bpf_try_make_writable net/core/filter.c:1682 [inline]
 bpf_try_make_writable net/core/filter.c:1688 [inline]
 bpf_try_make_head_writable net/core/filter.c:1696 [inline]
 ____bpf_clone_redirect net/core/filter.c:2481 [inline]
 bpf_clone_redirect+0x310/0x6d0 net/core/filter.c:2450
 ___bpf_prog_run+0x1297/0xeba0 kernel/bpf/core.c:2021
 __bpf_prog_run512+0xc5/0x100 kernel/bpf/core.c:2317
 bpf_dispatcher_nop_func include/linux/bpf.h:1376 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 bpf_test_run+0x496/0xe00 net/bpf/test_run.c:423
 bpf_prog_test_run_skb+0x2377/0x3200 net/bpf/test_run.c:1158
 bpf_prog_test_run+0x5c2/0xa40 kernel/bpf/syscall.c:4703
 __sys_bpf+0x873/0xeb0 kernel/bpf/syscall.c:6182
 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
 __x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:6272
 x64_sys_call+0x31c3/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Bytes 12-17 of 20 are uninitialized
Memory access of size 20 starts at ffff888046e1fa28
Data copied to user address 0000000020000ac0

CPU: 0 UID: 0 PID: 6680 Comm: syz.3.18 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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