=====================================================
BUG: KMSAN: uninit-value in qdisc_pkt_segs include/net/sch_generic.h:856 [inline]
BUG: KMSAN: uninit-value in bstats_update include/net/sch_generic.h:902 [inline]
BUG: KMSAN: uninit-value in qdisc_bstats_cpu_update include/net/sch_generic.h:908 [inline]
BUG: KMSAN: uninit-value in __dev_xmit_skb net/core/dev.c:4181 [inline]
BUG: KMSAN: uninit-value in __dev_queue_xmit+0x2fe8/0x5890 net/core/dev.c:4798
 qdisc_pkt_segs include/net/sch_generic.h:856 [inline]
 bstats_update include/net/sch_generic.h:902 [inline]
 qdisc_bstats_cpu_update include/net/sch_generic.h:908 [inline]
 __dev_xmit_skb net/core/dev.c:4181 [inline]
 __dev_queue_xmit+0x2fe8/0x5890 net/core/dev.c:4798
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 hsr_xmit net/hsr/hsr_forward.c:440 [inline]
 hsr_forward_do net/hsr/hsr_forward.c:581 [inline]
 hsr_forward_skb+0x2193/0x3c30 net/hsr/hsr_forward.c:743
 hsr_handle_frame+0xcee/0x1110 net/hsr/hsr_slave.c:81
 __netif_receive_skb_core+0xeb0/0x4c70 net/core/dev.c:6039
 __netif_receive_skb_list_core+0x2f9/0x1650 net/core/dev.c:6227
 __netif_receive_skb_list net/core/dev.c:6294 [inline]
 netif_receive_skb_list_internal+0xe9c/0x14e0 net/core/dev.c:6385
 gro_normal_list include/net/gro.h:524 [inline]
 gro_flush_normal include/net/gro.h:532 [inline]
 napi_complete_done+0x401/0x7b0 net/core/dev.c:6754
 gro_cell_poll+0x2c8/0x310 net/core/gro_cells.c:74
 __napi_poll+0xdc/0x8f0 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0xa5b/0x1c70 net/core/dev.c:7896
 handle_softirqs+0x168/0x6f0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656
 do_softirq+0x58/0x90 kernel/softirq.c:523
 __local_bh_enable_ip+0xa1/0xb0 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 tun_rx_batched+0x887/0x980 drivers/net/tun.c:-1
 tun_get_user+0x6002/0x7830 drivers/net/tun.c:1953
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:686
 ksys_write+0x1d9/0x470 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __ia32_sys_write+0x9a/0xf0 fs/read_write.c:746
 ia32_sys_call+0x3d5e/0x4340 arch/x86/include/generated/asm/syscalls_32.h:5
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x14a/0x310 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x37/0x80 arch/x86/entry/syscall_32.c:332
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:370
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was stored to memory at:
 qdisc_pkt_len_segs_init+0xa19/0xa80 net/core/dev.c:4135
 __dev_queue_xmit+0x303/0x5890 net/core/dev.c:4761
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 hsr_xmit net/hsr/hsr_forward.c:440 [inline]
 hsr_forward_do net/hsr/hsr_forward.c:581 [inline]
 hsr_forward_skb+0x2193/0x3c30 net/hsr/hsr_forward.c:743
 hsr_handle_frame+0xcee/0x1110 net/hsr/hsr_slave.c:81
 __netif_receive_skb_core+0xeb0/0x4c70 net/core/dev.c:6039
 __netif_receive_skb_list_core+0x2f9/0x1650 net/core/dev.c:6227
 __netif_receive_skb_list net/core/dev.c:6294 [inline]
 netif_receive_skb_list_internal+0xe9c/0x14e0 net/core/dev.c:6385
 gro_normal_list include/net/gro.h:524 [inline]
 gro_flush_normal include/net/gro.h:532 [inline]
 napi_complete_done+0x401/0x7b0 net/core/dev.c:6754
 gro_cell_poll+0x2c8/0x310 net/core/gro_cells.c:74
 __napi_poll+0xdc/0x8f0 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0xa5b/0x1c70 net/core/dev.c:7896
 handle_softirqs+0x168/0x6f0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656

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+0x9de/0x1780 mm/slub.c:5315
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586
 __alloc_skb+0x805/0x1030 net/core/skbuff.c:690
 __pskb_copy_fclone+0xcc/0x14c0 net/core/skbuff.c:2202
 __pskb_copy include/linux/skbuff.h:1447 [inline]
 hsr_create_tagged_frame+0x30b/0x1330 net/hsr/hsr_forward.c:350
 hsr_forward_do net/hsr/hsr_forward.c:-1 [inline]
 hsr_forward_skb+0x16ca/0x3c30 net/hsr/hsr_forward.c:743
 hsr_handle_frame+0xcee/0x1110 net/hsr/hsr_slave.c:81
 __netif_receive_skb_core+0xeb0/0x4c70 net/core/dev.c:6039
 __netif_receive_skb_list_core+0x2f9/0x1650 net/core/dev.c:6227
 __netif_receive_skb_list net/core/dev.c:6294 [inline]
 netif_receive_skb_list_internal+0xe9c/0x14e0 net/core/dev.c:6385
 gro_normal_list include/net/gro.h:524 [inline]
 gro_flush_normal include/net/gro.h:532 [inline]
 napi_complete_done+0x401/0x7b0 net/core/dev.c:6754
 gro_cell_poll+0x2c8/0x310 net/core/gro_cells.c:74
 __napi_poll+0xdc/0x8f0 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0xa5b/0x1c70 net/core/dev.c:7896
 handle_softirqs+0x168/0x6f0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656

CPU: 1 UID: 0 PID: 18572 Comm: syz.2.4137 Tainted: G        W    L      syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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