=====================================================
BUG: KMSAN: uninit-value in ip_tunnel_xmit+0x476/0x3610 net/ipv4/ip_tunnel.c:658
 ip_tunnel_xmit+0x476/0x3610 net/ipv4/ip_tunnel.c:658
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0xd4c/0xe20 net/ipv4/ip_gre.c:657
 __netdev_start_xmit include/linux/netdevice.h:4775 [inline]
 netdev_start_xmit include/linux/netdevice.h:4789 [inline]
 xmit_one+0x1de/0x6a0 net/core/dev.c:3532
 dev_hard_start_xmit+0xe5/0x370 net/core/dev.c:3548
 __dev_queue_xmit+0x1df2/0x2ed0 net/core/dev.c:4176
 dev_queue_xmit+0x2b/0x30 net/core/dev.c:4209
 __bpf_tx_skb net/core/filter.c:2113 [inline]
 __bpf_redirect_no_mac net/core/filter.c:2138 [inline]
 __bpf_redirect+0xc91/0x1420 net/core/filter.c:2161
 ____bpf_clone_redirect net/core/filter.c:2428 [inline]
 bpf_clone_redirect+0x324/0x470 net/core/filter.c:2400
 ___bpf_prog_run+0x7f7/0xac10 kernel/bpf/core.c:1835
 __bpf_prog_run512+0xdb/0x120 kernel/bpf/core.c:2075
 bpf_dispatcher_nop_func include/linux/bpf.h:804 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x592/0xd20 net/bpf/test_run.c:402
 bpf_prog_test_run_skb+0x1625/0x20b0 net/bpf/test_run.c:1111
 bpf_prog_test_run+0x6a0/0x730 kernel/bpf/syscall.c:3369
 __sys_bpf+0x7e3/0xe90 kernel/bpf/syscall.c:4681
 __do_sys_bpf kernel/bpf/syscall.c:4767 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4765 [inline]
 __ia32_sys_bpf+0x9c/0xe0 kernel/bpf/syscall.c:4765
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x95/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:754 [inline]
 slab_alloc_node mm/slub.c:3232 [inline]
 __kmalloc_node_track_caller+0x86c/0x1230 mm/slub.c:4963
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 pskb_expand_head+0x1aa/0x1a00 net/core/skbuff.c:1700
 skb_ensure_writable+0x3ce/0x460 net/core/skbuff.c:5614
 __bpf_try_make_writable net/core/filter.c:1654 [inline]
 bpf_try_make_writable net/core/filter.c:1660 [inline]
 bpf_try_make_head_writable net/core/filter.c:1668 [inline]
 ____bpf_clone_redirect net/core/filter.c:2422 [inline]
 bpf_clone_redirect+0x17b/0x470 net/core/filter.c:2400
 ___bpf_prog_run+0x7f7/0xac10 kernel/bpf/core.c:1835
 __bpf_prog_run512+0xdb/0x120 kernel/bpf/core.c:2075
 bpf_dispatcher_nop_func include/linux/bpf.h:804 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 bpf_test_run+0x592/0xd20 net/bpf/test_run.c:402
 bpf_prog_test_run_skb+0x1625/0x20b0 net/bpf/test_run.c:1111
 bpf_prog_test_run+0x6a0/0x730 kernel/bpf/syscall.c:3369
 __sys_bpf+0x7e3/0xe90 kernel/bpf/syscall.c:4681
 __do_sys_bpf kernel/bpf/syscall.c:4767 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4765 [inline]
 __ia32_sys_bpf+0x9c/0xe0 kernel/bpf/syscall.c:4765
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x95/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

CPU: 0 PID: 4720 Comm: syz-executor.3 Not tainted 5.18.0-syzkaller-16263-g2d0ce79ea812 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================