rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=f2ec/1/0x4000000000000000 softirq=74279/74279 fqs=83
rcu: 	(detected by 1, t=10502 jiffies, g=52649, q=245 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5832 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:mm_get_cid+0xab/0x130
Code: 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 49 c7 c5 c8 c4 98 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 dc 4b 06 0c 48 89 df 4c 89
RSP: 0018:ffffc90003ee7968 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff8881a793ed90 RCX: dffffc0000000000
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff8881a793ed90
RBP: 0000000080000000 R08: ffff8881a793ec13 R09: 1ffff11034f27d82
R10: dffffc0000000000 R11: ffffed1034f27d83 R12: dffffc0000000000
R13: 1ffffffff1b31899 R14: 0000000080000000 R15: 0000000000000002
FS:  000055557ef42500(0000) GS:ffff88818eab1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000003a80 CR3: 0000000111eb2000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __schedule+0x2169/0x5000
 schedule+0x165/0x360
 do_nanosleep+0x1c5/0x610
 hrtimer_nanosleep+0x169/0x360
 __se_sys_clock_nanosleep+0x339/0x390
 do_syscall_64+0xfa/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc08dbc2085
Code: Unable to access opcode bytes at 0x7fc08dbc205b.
RSP: 002b:00007ffe0f4a39b0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000000000000999 RCX: 00007fc08dbc2085
RDX: 00007ffe0f4a39f0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe0f4a3a5c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000003a0e4 R15: 00007ffe0f4a3ab0
 </TASK>
rcu: rcu_preempt kthread starved for 10336 jiffies! g52649 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:27752 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x14bc/0x5000
 schedule+0x165/0x360
 schedule_timeout+0x12b/0x270
 rcu_gp_fqs_loop+0x301/0x1540
 rcu_gp_kthread+0x99/0x390
 kthread+0x711/0x8a0
 ret_from_fork+0x599/0xb30
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 68 Comm: kworker/u10:4 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
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:smp_call_function_many_cond+0xccf/0x12b0
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 4a 94 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 f5 8f 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 d9 8f
RSP: 0018:ffffc900017a6020 EFLAGS: 00000293
RAX: ffffffff81b5ba87 RBX: 1ffff11024248545 RCX: ffff888169243a80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900017a61a0 R08: ffff888110e3d507 R09: 1ffff110221c7aa0
R10: dffffc0000000000 R11: ffffffff8175e570 R12: ffff888121242a28
R13: dffffc0000000000 R14: ffff88823c63b9c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a9eb1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0aa17dd58 CR3: 0000000175f1a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x6b1/0x1280
 ptep_clear_flush+0x120/0x170
 page_vma_mkclean_one+0x406/0x740
 page_mkclean_one+0x1c0/0x280
 __rmap_walk_file+0x467/0x620
 folio_mkclean+0x297/0x390
 folio_clear_dirty_for_io+0x1f5/0x880
 mpage_submit_folio+0x86/0x2b0
 mpage_process_page_bufs+0x6d5/0x8e0
 mpage_prepare_extent_to_map+0xe5b/0x16d0
 ext4_do_writepages+0xba0/0x45c0
 ext4_writepages+0x205/0x350
 do_writepages+0x32e/0x550
 __writeback_single_inode+0x133/0x1240
 writeback_sb_inodes+0x93a/0x1870
 __writeback_inodes_wb+0x111/0x240
 wb_writeback+0x43f/0xaa0
 wb_workfn+0xad2/0xed0
 process_scheduled_works+0xad1/0x1770
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x599/0xb30
 ret_from_fork_asm+0x1a/0x30
 </TASK>
