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BUG: KMSAN: use-after-free in skb_unref include/linux/skbuff.h:1011 [inline]
BUG: KMSAN: use-after-free in kfree_skb+0x23c/0x4c0 net/core/skbuff.c:693
CPU: 1 PID: 13066 Comm: syz-fuzzer Not tainted 5.4.0-rc5+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x128/0x220 mm/kmsan/kmsan_report.c:108
 __msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:245
 skb_unref include/linux/skbuff.h:1011 [inline]
 kfree_skb+0x23c/0x4c0 net/core/skbuff.c:693
 hsr_forward_skb+0x2d7c/0x3070 net/hsr/hsr_forward.c:371
 send_hsr_supervision_frame+0x10a6/0x14f0 net/hsr/hsr_device.c:306
 hsr_announce+0x1eb/0x370 net/hsr/hsr_device.c:334
 call_timer_fn+0x232/0x530 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers+0xd60/0x1270 kernel/time/timer.c:1773
 run_timer_softirq+0x2d/0x50 kernel/time/timer.c:1786
 __do_softirq+0x4a1/0x83a kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:375 [inline]
 irq_exit+0x230/0x280 kernel/softirq.c:416
 exiting_irq+0xe/0x10 arch/x86/include/asm/apic.h:536
 smp_apic_timer_interrupt+0x48/0x70 arch/x86/kernel/apic/apic.c:1139
 apic_timer_interrupt+0x2e/0x40 arch/x86/entry/entry_64.S:837
 </IRQ>
RIP: 0033:0x41068d
Code: 98 00 00 00 48 8d ac 24 98 00 00 00 31 c0 48 89 44 24 50 8b 05 b8 99 4a 01 83 f8 02 0f 84 54 08 00 00 48 8b 84 24 a8 00 00 00 <48> 85 c0 0f 84 d2 07 00 00 8b 0d 6c a1 4a 01 85 c9 74 4f 48 8b 8c
RSP: 002b:000000c43a6e5e00 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000018 RBX: 000000c439dffa40 RCX: 000000c42006ef00
RDX: 000000c42713d840 RSI: 000000c4238420c0 RDI: 000000000000a0b0
RBP: 000000c43a6e5e98 R08: 000000c439e100b8 R09: 0000000000000000
R10: 00000000009d1f1e R11: 0000000000000004 R12: 0000000000000000
R13: 0000000000000018 R14: 0000000000000013 R15: 0000000000000028

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
 kmsan_internal_poison_shadow+0x60/0x120 mm/kmsan/kmsan.c:134
 kmsan_slab_free+0x8d/0xf0 mm/kmsan/kmsan_hooks.c:108
 slab_free_freelist_hook mm/slub.c:1473 [inline]
 slab_free mm/slub.c:3047 [inline]
 kmem_cache_free+0x2d1/0x2b70 mm/slub.c:3063
 kfree_skbmem net/core/skbuff.c:644 [inline]
 __kfree_skb+0x1dd/0x210 net/core/skbuff.c:680
 consume_skb+0x2b0/0x2e0 net/core/skbuff.c:838
 packet_rcv+0x242/0x2110 net/packet/af_packet.c:2146
 dev_queue_xmit_nit+0x1125/0x1200 net/core/dev.c:2077
 xmit_one net/core/dev.c:3276 [inline]
 dev_hard_start_xmit+0x21e/0xab0 net/core/dev.c:3296
 __dev_queue_xmit+0x35b6/0x4200 net/core/dev.c:3873
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3906
 hsr_xmit net/hsr/hsr_forward.c:228 [inline]
 hsr_forward_do net/hsr/hsr_forward.c:285 [inline]
 hsr_forward_skb+0x2133/0x3070 net/hsr/hsr_forward.c:361
 send_hsr_supervision_frame+0x10a6/0x14f0 net/hsr/hsr_device.c:306
 hsr_announce+0x1eb/0x370 net/hsr/hsr_device.c:334
 call_timer_fn+0x232/0x530 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers+0xd60/0x1270 kernel/time/timer.c:1773
 run_timer_softirq+0x2d/0x50 kernel/time/timer.c:1786
 __do_softirq+0x4a1/0x83a kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:375 [inline]
 irq_exit+0x230/0x280 kernel/softirq.c:416
 exiting_irq+0xe/0x10 arch/x86/include/asm/apic.h:536
 smp_apic_timer_interrupt+0x48/0x70 arch/x86/kernel/apic/apic.c:1139
 apic_timer_interrupt+0x2e/0x40 arch/x86/entry/entry_64.S:837
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