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BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:131 [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:131 [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+0x299/0x3f0 net/socket.c:306
 ____sys_recvmsg+0x232/0x620 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+0x96d/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 packet_recvmsg+0x15a1/0x2510 net/packet/af_packet.c:3518
 sock_recvmsg_nosec+0x1e2/0x270 net/socket.c:1078
 ____sys_recvmsg+0x4e5/0x620 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+0x96d/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:300
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 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:201
 dev_parse_header include/linux/netdevice.h:3450 [inline]
 packet_rcv+0x10d3/0x2430 net/packet/af_packet.c:2186
 dev_queue_xmit_nit+0xfa4/0x1170 net/core/dev.c:2606
 xmit_one net/core/dev.c:3884 [inline]
 dev_hard_start_xmit+0x187/0xad0 net/core/dev.c:3904
 sch_direct_xmit+0x3b2/0xcf0 net/sched/sch_generic.c:347
 __dev_xmit_skb net/core/dev.c:4203 [inline]
 __dev_queue_xmit+0x301d/0x5980 net/core/dev.c:4819
 dev_queue_xmit include/linux/netdevice.h:3385 [inline]
 __bpf_tx_skb net/core/filter.c:2152 [inline]
 __bpf_redirect_common net/core/filter.c:2196 [inline]
 __bpf_redirect+0x162e/0x1760 net/core/filter.c:2203
 ____bpf_clone_redirect net/core/filter.c:2493 [inline]
 bpf_clone_redirect+0x4a6/0x6c0 net/core/filter.c:2456
 ___bpf_prog_run+0x13e8/0xea90 kernel/bpf/core.c:2067
 __bpf_prog_run512+0xc5/0x100 kernel/bpf/core.c:2363
 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 bpf_test_run+0x493/0xdf0 net/bpf/test_run.c:423
 bpf_prog_test_run_skb+0x22a5/0x3050 net/bpf/test_run.c:1159
 bpf_prog_test_run+0x5bb/0x9f0 kernel/bpf/syscall.c:4743
 __sys_bpf+0x925/0xee0 kernel/bpf/syscall.c:6267
 __do_sys_bpf kernel/bpf/syscall.c:6362 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6360 [inline]
 __x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:6360
 x64_sys_call+0x13d0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 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:4545 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_node_noprof+0x3cd/0x12d0 mm/slub.c:4918
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 pskb_expand_head+0x2ef/0x1e00 net/core/skbuff.c:2312
 skb_ensure_writable+0x44e/0x510 net/core/skbuff.c:6362
 __bpf_try_make_writable net/core/filter.c:1681 [inline]
 bpf_try_make_writable net/core/filter.c:1687 [inline]
 bpf_try_make_head_writable net/core/filter.c:1695 [inline]
 ____bpf_clone_redirect net/core/filter.c:2487 [inline]
 bpf_clone_redirect+0x301/0x6c0 net/core/filter.c:2456
 ___bpf_prog_run+0x13e8/0xea90 kernel/bpf/core.c:2067
 __bpf_prog_run512+0xc5/0x100 kernel/bpf/core.c:2363
 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 bpf_test_run+0x493/0xdf0 net/bpf/test_run.c:423
 bpf_prog_test_run_skb+0x22a5/0x3050 net/bpf/test_run.c:1159
 bpf_prog_test_run+0x5bb/0x9f0 kernel/bpf/syscall.c:4743
 __sys_bpf+0x925/0xee0 kernel/bpf/syscall.c:6267
 __do_sys_bpf kernel/bpf/syscall.c:6362 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6360 [inline]
 __x64_sys_bpf+0xa4/0xf0 kernel/bpf/syscall.c:6360
 x64_sys_call+0x13d0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 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 ffff8880503eba38
Data copied to user address 0000000020000ac0

CPU: 1 UID: 0 PID: 6475 Comm: syz.4.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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