rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=9b04/1/0x4000000000000000 softirq=17833/17833 fqs=16
rcu: 	(detected by 1, t=10502 jiffies, g=15849, q=429 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7071 Comm: syz.1.449 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+0x5b0/0x1120
Code: 00 00 31 ed 31 db e9 7b 01 00 00 49 c7 c4 98 5e 1b 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 e3 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:ffffc90003f07c48 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff888172212410 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff888172212410
RBP: 0000000080000000 R08: 1ffff1102e442331 R09: 0000000000000000
R10: ffff888172211ad4 R11: fffff520007e0f78 R12: 1ffffffff1c36bd3
R13: 0000000080000000 R14: 0000000000000002 R15: ffff888172211880
FS:  00007f6067ff66c0(0000) GS:ffff88818de62000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fe15ff8 CR3: 00000001bbd3c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 bprm_execve+0xda1/0x1460
 do_execveat_common+0x50d/0x690
 __x64_sys_execveat+0xc7/0xf0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6069d9c819
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:00007f6067ff6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007f606a015fa0 RCX: 00007f6069d9c819
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f6069e32c91 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f606a016038 R14: 00007f606a015fa0 R15: 00007ffd6b2c4c78
 </TASK>
rcu: rcu_preempt kthread starved for 10420 jiffies! g15849 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:28120 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x11d0
 rcu_gp_kthread+0x9e/0x2b0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 5815 Comm: syz-executor 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+0xce5/0x12c0
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 c4 e6 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 6f e2 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 53 e2
RSP: 0000:ffffc900065cf840 EFLAGS: 00000293
RAX: ffffffff81b9b25d RBX: 1ffff11024208559 RCX: ffff88810fca57c0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900065cf970 R08: ffffffff9011e6b7 R09: 1ffffffff2023cd6
R10: dffffc0000000000 R11: fffffbfff2023cd7 R12: ffff888121042ac8
R13: dffffc0000000000 R14: ffff88823c63bf80 R15: 0000000000000000
FS:  000055558ef9f500(0000) GS:ffff8882a9462000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558efbaa28 CR3: 0000000119c74000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000009 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x5c3/0x10c0
 ptep_clear_flush+0x120/0x170
 do_wp_page+0x3da7/0x4cc0
 handle_mm_fault+0x151d/0x3170
 do_user_addr_fault+0xa73/0x1340
 exc_page_fault+0x6a/0xc0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f6aead613a0
Code: ba 28 00 48 8d 0c 1e 49 39 d0 49 89 48 60 0f 95 c2 48 29 d8 0f b6 d2 48 83 c8 01 48 c1 e2 02 48 09 da 48 83 ca 01 48 89 56 08 <48> 89 41 08 48 8d 4e 10 eb b0 48 8d 0d 37 df 0c 00 ba 9e 10 00 00
RSP: 002b:00007ffcf08bc4c0 EFLAGS: 00010206
RAX: 00000000000185e1 RBX: 0000000000008040 RCX: 000055558efbaa20
RDX: 0000000000008041 RSI: 000055558efb29e0 RDI: 0000000000000004
RBP: 0000000000000802 R08: 00007f6aeafece20 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000008030
R13: 0000000000000000 R14: 00007f6aeafece80 R15: 0000000000000000
 </TASK>
