===================================================== BUG: KMSAN: uninit-value in update_stack_state+0x974/0xb40 arch/x86/kernel/unwind_frame.c:238 CPU: 1 PID: 8888 Comm: syz-fuzzer Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 update_stack_state+0x974/0xb40 arch/x86/kernel/unwind_frame.c:238 unwind_next_frame+0x8c6/0xed0 arch/x86/kernel/unwind_frame.c:305 arch_stack_walk+0x338/0x3d0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x117/0x1a0 kernel/stacktrace.c:123 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116 skb_ext_maybe_cow net/core/skbuff.c:6118 [inline] skb_ext_add+0x477/0xbc0 net/core/skbuff.c:6180 nf_bridge_unshare net/bridge/br_netfilter_hooks.c:160 [inline] br_nf_forward_ip+0x19a/0x2480 net/bridge/br_netfilter_hooks.c:589 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0x17b/0x460 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:262 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] __br_forward+0x96e/0xec0 net/bridge/br_forward.c:109 deliver_clone net/bridge/br_forward.c:125 [inline] br_flood+0xf26/0x1130 net/bridge/br_forward.c:232 br_handle_frame_finish+0x1e35/0x2020 net/bridge/br_input.c:166 br_nf_hook_thresh+0x576/0x700 net/bridge/br_netfilter_hooks.c:1021 br_nf_pre_routing_finish_ipv6+0xf91/0x1110 net/bridge/br_netfilter_ipv6.c:187 NF_HOOK include/linux/netfilter.h:307 [inline] br_nf_pre_routing_ipv6+0x7e2/0x8a0 net/bridge/br_netfilter_ipv6.c:236 br_nf_pre_routing+0xfe7/0x25a0 net/bridge/br_netfilter_hooks.c:505 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_bridge_pre net/bridge/br_input.c:228 [inline] br_handle_frame+0xc83/0x25a0 net/bridge/br_input.c:356 __netif_receive_skb_core+0x3710/0x6520 net/core/dev.c:5175 __netif_receive_skb_one_core net/core/dev.c:5279 [inline] __netif_receive_skb+0x164/0x670 net/core/dev.c:5395 process_backlog+0x50d/0xba0 net/core/dev.c:6239 napi_poll+0x43b/0xfd0 net/core/dev.c:6684 net_rx_action+0x35c/0xd40 net/core/dev.c:6752 __do_softirq+0x2ea/0x7f5 kernel/softirq.c:293 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711 __run_on_irqstack arch/x86/include/asm/irq_stack.h:23 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] do_softirq_own_stack+0x7c/0xa0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:390 [inline] __irq_exit_rcu+0x226/0x270 kernel/softirq.c:420 irq_exit_rcu+0xe/0x10 kernel/softirq.c:432 sysvec_call_function_single+0x107/0x130 arch/x86/kernel/smp.c:243 asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:601 RIP: 0010:finish_lock_switch+0x2b/0x40 kernel/sched/core.c:3198 Code: 48 89 e5 53 48 89 fb e8 c3 d8 b9 00 8b b8 88 0c 00 00 48 8b 00 48 85 c0 75 12 48 89 df e8 4d d2 b9 00 c6 00 00 c6 03 00 fb 5b <5d> c3 e8 fe d7 b9 00 eb e7 66 90 66 2e 0f 1f 84 00 00 00 00 00 55 RSP: 0018:ffff88804d49b7b0 EFLAGS: 00000282 RAX: ffff88821fdb2340 RBX: ffff88810bed0000 RCX: 000000021fd13340 RDX: ffff88821fd13340 RSI: 00000000000004a0 RDI: ffff88812fd94340 RBP: ffff88804d49b7b0 R08: ffffea000000000f R09: ffff88812fffa000 R10: 0000000000000004 R11: 0000000000000000 R12: ffff88804d4d89d8 R13: ffff88804d4d8000 R14: 0000000000000002 R15: ffff88812fd94340 finish_task_switch+0xd2/0x2f0 kernel/sched/core.c:3303 context_switch kernel/sched/core.c:3467 [inline] __schedule+0x4ae/0x520 kernel/sched/core.c:4195 schedule+0x260/0x330 kernel/sched/core.c:4270 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x503/0x6d0 kernel/futex.c:2634 futex_wait+0x422/0xae0 kernel/futex.c:2740 do_futex+0x3ac2/0x6ae0 kernel/futex.c:3811 __do_sys_futex kernel/futex.c:3872 [inline] __se_sys_futex+0x559/0x960 kernel/futex.c:3840 __x64_sys_futex+0x6e/0x90 kernel/futex.c:3840 do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x469143 Code: Bad RIP value. RSP: 002b:000000c0000f9d98 EFLAGS: 00000286 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 000000c00003f180 RCX: 0000000000469143 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000c00003f2c8 RBP: 000000c0000f9de0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000003 R13: 000000c000001800 R14: 000000000000007f R15: ffffffffffecbb6e Local variable ----opts@tcp_current_mss created at: tcp_current_mss+0x8b/0x410 net/ipv4/tcp_output.c:1662 tcp_current_mss+0x8b/0x410 net/ipv4/tcp_output.c:1662 =====================================================