rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=029c/1/0x4000000000000000 softirq=205105/205108 fqs=1
rcu: 	(detected by 1, t=10502 jiffies, g=188845, q=172 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 14959 Comm: syz.1.10683 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:mm_get_cid+0xab/0x130
Code: 41 5c 41 5d 41 5e 41 5f 5d e9 01 0b e8 09 cc 49 c7 c5 c8 14 d8 8d 49 c1 ed 03 bd 00 00 00 80 eb 07 44 89 f0 f7 d8 71 d4 f3 90 <43> 0f b6 44 25 00 84 c0 75 41 44 8b 3d bc 9e 44 0c 48 89 df 4c 89
RSP: 0018:ffffc900055b7988 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff88817452c8d0 RCX: dffffc0000000000
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff88817452c8d0
RBP: 0000000080000000 R08: ffff88817452c753 R09: 1ffff1102e8a58ea
R10: dffffc0000000000 R11: ffffed102e8a58eb R12: dffffc0000000000
R13: 1ffffffff1bb0299 R14: 0000000080000000 R15: 0000000000000002
FS:  000055557bef0500(0000) GS:ffff88818e329000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa96a9e6ff8 CR3: 000000018f408000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __schedule+0x21ae/0x4fb0
 schedule+0x164/0x360
 do_nanosleep+0x1c2/0x620
 hrtimer_nanosleep+0x188/0x390
 __se_sys_clock_nanosleep+0x35b/0x3b0
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd8f0b5b58e
Code: Unable to access opcode bytes at 0x7fd8f0b5b564.
RSP: 002b:00007ffeff31cf38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 000055557bef0500 RCX: 00007fd8f0b5b58e
RDX: 00007ffeff31cf90 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fd8f0e17da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000d0aa7
R13: 00007fd8f0e1609c R14: 00000000000d0811 R15: 00007fd8f0e16090
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g188845 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:27504 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x1560
 rcu_gp_kthread+0x9d/0x3b0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 5833 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
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+0xce5/0x1270
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 94 b4 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 3f b0 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 23 b0
RSP: 0018:ffffc90004ec7640 EFLAGS: 00000293
RAX: ffffffff81b6d15d RBX: 1ffff1102420856d RCX: ffff88810374d7c0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004ec7768 R08: ffffffff8fced877 R09: 1ffffffff1f9db0e
R10: dffffc0000000000 R11: fffffbfff1f9db0f R12: ffff888121042b68
R13: dffffc0000000000 R14: ffff88823c63bb00 R15: 0000000000000000
FS:  0000555560d97500(0000) GS:ffff8882a9929000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4b3f1456b8 CR3: 000000010d010000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x5c3/0x10c0
 dup_mmap+0x1620/0x1bb0
 copy_mm+0x13b/0x4b0
 copy_process+0x166e/0x3980
 kernel_clone+0x248/0x870
 __x64_sys_clone+0x1b6/0x230
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4b3e3c3752
Code: 89 e7 e8 f1 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:00007ffe5fa318a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffe5fa318a0 RCX: 00007f4b3e3c3752
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffe5fa31a2c R08: 0000000000000000 R09: 0000000000000001
R10: 0000555560d977d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 00000000000d099b R15: 00007ffe5fa31a80
 </TASK>
