================================================================== BUG: KMSAN: uninit-value in memcmp+0x117/0x180 lib/string.c:865 CPU: 1 PID: 14067 Comm: syz-executor.1 Not tainted 5.0.0+ #16 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+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x131/0x2a0 mm/kmsan/kmsan.c:636 __msan_warning+0x7a/0xf0 mm/kmsan/kmsan_instr.c:310 memcmp+0x117/0x180 lib/string.c:865 __hw_addr_del_ex net/core/dev_addr_lists.c:123 [inline] __dev_mc_del+0x16c/0x690 net/core/dev_addr_lists.c:810 dev_mc_del+0x6d/0x80 net/core/dev_addr_lists.c:828 igmp6_group_dropped+0x2d7/0x12a0 net/ipv6/mcast.c:712 ipv6_mc_down+0xc8/0x2e0 net/ipv6/mcast.c:2542 addrconf_ifdown+0x20d7/0x2540 net/ipv6/addrconf.c:3806 addrconf_notify+0x5de/0x57a0 net/ipv6/addrconf.c:3462 notifier_call_chain kernel/notifier.c:93 [inline] __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x13d/0x240 kernel/notifier.c:401 call_netdevice_notifiers_info net/core/dev.c:1739 [inline] call_netdevice_notifiers_extack net/core/dev.c:1751 [inline] call_netdevice_notifiers net/core/dev.c:1765 [inline] dev_close_many+0x621/0xa10 net/core/dev.c:1508 rollback_registered_many+0x9a4/0x21f0 net/core/dev.c:8079 rollback_registered net/core/dev.c:8144 [inline] unregister_netdevice_queue+0x55d/0xa70 net/core/dev.c:9191 unregister_netdevice include/linux/netdevice.h:2642 [inline] __tun_detach+0x21be/0x2b00 drivers/net/tun.c:727 tun_detach drivers/net/tun.c:744 [inline] tun_chr_close+0xda/0x1c0 drivers/net/tun.c:3435 __fput+0x4d1/0xbb0 fs/file_table.c:278 ____fput+0x37/0x40 fs/file_table.c:309 task_work_run+0x22e/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:166 [inline] prepare_exit_to_usermode+0x321/0x420 arch/x86/entry/common.c:197 syscall_return_slowpath+0xb2/0x650 arch/x86/entry/common.c:268 do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x411fc1 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 e4 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:0000000000a4fd70 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000411fc1 RDX: 0000000000000000 RSI: 0000000000740718 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000106e19 R09: 0000000000106e19 R10: 0000000000a4fca0 R11: 0000000000000293 R12: 0000000000000001 R13: 0000000000a4fdb0 R14: 0000000000000000 R15: 0000000000a4fdc0 Local variable description: ----buf@igmp6_group_dropped Variable was created at: igmp6_group_dropped+0x5a/0x12a0 net/ipv6/mcast.c:700 ipv6_mc_down+0xc8/0x2e0 net/ipv6/mcast.c:2542 ==================================================================