rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=cb9c/1/0x4000000000000000 softirq=128189/128195 fqs=0
rcu: 	(detected by 1, t=10506 jiffies, g=127201, q=147 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 21155 Comm: syz.4.4984 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:sched_mm_cid_fork+0x657/0x10e0
Code: c7 03 00 00 00 40 e9 19 01 00 00 49 c7 c4 b8 8e 26 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 09 fe ff ff f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 40 44 8b 35
RSP: 0018:ffffc90003697c48 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff88810b5f17d0 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff88810b5f17d0
RBP: 0000000080000000 R08: 1ffff110216be1a9 R09: 0000000000000000
R10: ffff88810b5f0e8c R11: fffff520006d2f78 R12: 1ffffffff1c4d1d7
R13: 0000000080000000 R14: 0000000000000002 R15: ffff88810b5f0c40
FS:  00007fda6a5a46c0(0000) GS:ffff88818dc90000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fda697ea4c0 CR3: 0000000112702000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 bprm_execve+0xdb7/0x1440
 do_execveat_common+0x50d/0x690
 __x64_sys_execveat+0xc7/0xf0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda6979cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fda6a5a4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007fda69a15fa0 RCX: 00007fda6979cdd9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007fda69832d69 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda69a16038 R14: 00007fda69a15fa0 R15: 00007ffdad37e038
 </TASK>
rcu: rcu_preempt kthread starved for 10506 jiffies! g127201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27536 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x11d0
 rcu_gp_kthread+0x9e/0x2b0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 21140 Comm: syz.7.4977 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:smp_call_function_many_cond+0xfcf/0x13d0
Code: 79 45 8b 2e 44 89 ee 83 e6 01 31 ff e8 fa fc 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 a5 f8 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 8a f8 0b
RSP: 0018:ffffc90000ac77c0 EFLAGS: 00000293
RAX: ffffffff81b9abb6 RBX: ffff88823c63c2c8 RCX: ffff88816a179d80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000ac7900 R08: ffff8881addd17c7 R09: 1ffff11035bba2f8
R10: dffffc0000000000 R11: ffffed1035bba2f9 R12: 1ffff110242085b9
R13: dffffc0000000000 R14: ffff888121042dc8 R15: 0000000000000000
FS:  0000555563312500(0000) GS:ffff8882a9290000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fda6a582ff8 CR3: 000000011df0c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x5c3/0x10b0
 tlb_flush_mmu+0x1a0/0xa10
 tlb_finish_mmu+0xf9/0x230
 exit_mmap+0x498/0x9e0
 __mmput+0x118/0x430
 exit_mm+0x18e/0x250
 do_exit+0x6a2/0x22c0
 do_group_exit+0x21b/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x221a/0x2240
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f26efb9cdd9
Code: Unable to access opcode bytes at 0x7f26efb9cdaf.
RSP: 002b:00007ffc092a90a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f26efb9cdd9
RDX: 00007f26eedf9000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffc092a910c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000460
R13: 00000000000927c0 R14: 00000000000a0665 R15: 00007ffc092a9160
 </TASK>
