rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=fb9c/1/0x4000000000000000 softirq=29387/29388 fqs=0
rcu: 	(detected by 0, t=10506 jiffies, g=25149, q=510 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7970 Comm: syz.4.384 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 4e 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:ffffc90005537c48 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff88810e3d17d0 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff88810e3d17d0
RBP: 0000000080000000 R08: 1ffff11021c7a1a9 R09: 0000000000000000
R10: ffff88810e3d0e94 R11: fffff52000aa6f78 R12: 1ffffffff1c369d3
R13: 0000000080000000 R14: 0000000000000002 R15: ffff88810e3d0c40
FS:  00007fbf9672f6c0(0000) GS:ffff8882a9454000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2ae0c8 CR3: 000000010e048000 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: 0033:0x7fbf9579c819
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:00007fbf9672f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007fbf95a15fa0 RCX: 00007fbf9579c819
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007fbf95832c91 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf95a16038 R14: 00007fbf95a15fa0 R15: 00007ffe1c4a0348
 </TASK>
rcu: rcu_preempt kthread starved for 10506 jiffies! g25149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:28288 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: 0 UID: 0 PID: 7679 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 d4 eb 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f e7 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 63 e7
RSP: 0018:ffffc90009d7f580 EFLAGS: 00000293
RAX: ffffffff81b9d88d RBX: 1ffff110478c813d RCX: ffff888173121d40
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90009d7f6a8 R08: ffffffff9011d8b7 R09: 1ffffffff2023b16
R10: dffffc0000000000 R11: fffffbfff2023b17 R12: ffff88823c6409e8
R13: dffffc0000000000 R14: ffff88812103c000 R15: 0000000000000001
FS:  0000555578202500(0000) GS:ffff88818de54000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcb407456b8 CR3: 00000001a8d6e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x5c3/0x10c0
 dup_mmap+0x17a2/0x1d90
 copy_mm+0x13b/0x4a0
 copy_process+0x18b6/0x3cd0
 kernel_clone+0x248/0x8e0
 __x64_sys_clone+0x1b6/0x230
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcb3f9c5292
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffc853dd2d0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffc853dd2d0 RCX: 00007fcb3f9c5292
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffc853dd45c R08: 0000000000000000 R09: 0000000000000001
R10: 00005555782027d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 0000000000022f1f R15: 00007ffc853dd4b0
 </TASK>
