syzbot

bridge0: port 1(bridge_slave_0) entered forwarding state
IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): bridge0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): bridge0: link becomes ready
==================================================================
BUG: KMSAN: uninit-value in task_fork_fair+0x4fa/0x9a0 kernel/sched/fair.c:9476
CPU: 1 PID: 4594 Comm: syz-executor1 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 task_fork_fair+0x4fa/0x9a0 kernel/sched/fair.c:9476
 sched_fork+0x747/0x1280 kernel/sched/core.c:2407
 copy_process+0x1f4a/0x9bb0 kernel/fork.c:1764
 _do_fork+0x311/0xf00 kernel/fork.c:2088
 SYSC_clone+0xf6/0x110 kernel/fork.c:2195
 SyS_clone+0x77/0xa0 kernel/fork.c:2189
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x41f799
RSP: 002b:0000000000a3fad0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000041f799
RDX: 0000000000a3fadc RSI: 0000000000000000 RDI: 0000000000100011
RBP: 0000000000a3fc80 R08: 0000000000a44a60 R09: 000000000000002a
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000a3feb0
R13: 0000000000a3fe28 R14: 0000000000000000 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:528
 set_next_entity+0x2d0/0xb60 kernel/sched/fair.c:4209
 pick_next_task_fair+0x1b09/0x1f70 kernel/sched/fair.c:6724
 pick_next_task+0x1b4/0x410 kernel/sched/core.c:3290
 __schedule+0x211/0x730 kernel/sched/core.c:3420
 do_task_dead+0xa4/0xd0 kernel/sched/core.c:3478
 do_exit+0x340e/0x38d0 kernel/exit.c:924
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 SYSC_exit_group+0x21/0x30 kernel/exit.c:981
 SyS_exit_group+0x25/0x30 kernel/exit.c:979
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:528
 __rb_insert lib/rbtree.c:104 [inline]
 rb_insert_color_cached+0xddf/0x1370 lib/rbtree.c:469
 __enqueue_entity kernel/sched/fair.c:576 [inline]
 enqueue_entity kernel/sched/fair.c:4045 [inline]
 enqueue_task_fair+0x17f6/0x43a0 kernel/sched/fair.c:5219
 enqueue_task kernel/sched/core.c:774 [inline]
 activate_task kernel/sched/core.c:793 [inline]
 ttwu_activate kernel/sched/core.c:1664 [inline]
 ttwu_do_activate kernel/sched/core.c:1723 [inline]
 ttwu_queue kernel/sched/core.c:1868 [inline]
 try_to_wake_up+0x13cc/0x20a0 kernel/sched/core.c:2081
 default_wake_function+0x92/0xb0 kernel/sched/core.c:3699
 child_wait_callback+0x2fc/0x350 kernel/exit.c:1489
 __wake_up_common+0x44f/0xa60 kernel/sched/wait.c:97
 __wake_up_common_lock+0x196/0x370 kernel/sched/wait.c:125
 __wake_up_sync_key+0xcf/0x120 kernel/sched/wait.c:203
 __wake_up_parent+0x94/0xb0 kernel/exit.c:1494
 do_notify_parent+0xd76/0xe30 kernel/signal.c:1817
 exit_notify kernel/exit.c:720 [inline]
 do_exit+0x28b3/0x38d0 kernel/exit.c:887
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 SYSC_exit_group+0x21/0x30 kernel/exit.c:981
 SyS_exit_group+0x25/0x30 kernel/exit.c:979
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Local variable description: ----wo@kernel_wait4
Variable was created at:
 kernel_wait4+0x85/0x4b0 kernel/exit.c:1634
 SYSC_wait4+0x111/0x280 kernel/exit.c:1679
==================================================================