rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (2 ticks this GP) idle=429c/1/0x4000000000000000 softirq=29822/29825 fqs=1
rcu: 	(detected by 1, t=10505 jiffies, g=20809, q=293 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7990 Comm: syz.6.462 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:validate_chain+0x1e1/0x2140
Code: cc 48 ff cb f7 c1 00 60 00 00 74 c8 e9 8d 00 00 00 48 c7 c7 90 b1 00 8e 4c 89 fe e8 19 0e 62 03 48 8b 14 24 eb c9 48 8b 48 18 <4c> 39 f9 0f 84 b2 00 00 00 48 8b 40 08 48 85 c0 0f 84 c2 fe ff ff
RSP: 0018:ffffc90000007638 EFLAGS: 00000093
RAX: ffffffff93a8b010 RBX: 000000000002c50a RCX: d6bf87c490213bdc
RDX: 0000000000000000 RSI: ffff88801fc20af0 RDI: ffff88801fc20000
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81ada78b
R10: dffffc0000000000 R11: ffffed1009604f51 R12: 0000000000000001
R13: ffff88801fc20af0 R14: ffff88801fc20af0 R15: d6bf87c490213bdc
FS:  00007f28327c16c0(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30f1fff8 CR3: 000000001fc74000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 _raw_spin_lock_irqsave+0xa7/0xf0
 hrtimer_try_to_cancel+0x22b/0x420
 hrtimer_cancel+0x3b/0x50
 cpu_clock_event_stop+0xd9/0x130
 __perf_event_overflow+0x580/0xe40
 perf_swevent_hrtimer+0x3c5/0x550
 __hrtimer_run_queues+0x4e0/0xc60
 hrtimer_interrupt+0x45b/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:do_syscall_64+0xc3/0x3b0
Code: 00 48 8b 7d 08 48 89 7b 18 e8 09 5a 00 00 0f 1f 44 00 00 0f 1f 44 00 00 90 e8 d9 6a 4d f6 90 90 e8 82 6a 4d f6 fb 49 8b 57 08 <f6> c2 3f 74 0e 4c 89 f7 4c 89 ee e8 fd 5d 30 f6 49 89 c4 90 90 41
RSP: 0018:ffffc9000691fef0 EFLAGS: 00000286
RAX: c7e1557b6f8daa00 RBX: ffffc9000691fef0 RCX: c7e1557b6f8daa00
RDX: 0000000000000000 RSI: ffffffff8d9ba160 RDI: ffffffff8be33e00
RBP: ffffc9000691ff48 R08: ffffffff8fa3a837 R09: 1ffffffff1f47506
R10: dffffc0000000000 R11: fffffbfff1f47507 R12: 00000000000000ca
R13: 00000000000000ca R14: ffffc9000691ff58 R15: ffff88801fc20000
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f283198eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f28327c10e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f2831bd5fa8 RCX: 00007f283198eba9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f2831bd5fac
RBP: 00007f2831bd5fa0 R08: 7fffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2831bd6038 R14: 00007ffc3a82dee0 R15: 00007ffc3a82dfc8
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g20809 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:27304 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x12b/0x270
 rcu_gp_fqs_loop+0x301/0x1540
 rcu_gp_kthread+0x99/0x390
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 65 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:__sanitizer_cov_trace_pc+0x8/0x70
Code: 8b 3d f4 73 fe 0b 48 89 de 5b e9 73 ac 58 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 08 d0 a0 92 65 8b 15 18 0f e1 10 81 e2 00 01 ff 00
RSP: 0018:ffffc9000173e398 EFLAGS: 00000202
RAX: ffffffff81b4621b RBX: 1ffff11009608341 RCX: ffff8881057ed640
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000173e520 R08: ffff8881113faa47 R09: 1ffff1102227f548
R10: dffffc0000000000 R11: ffffffff8174be80 R12: ffff88804b041a08
R13: dffffc0000000000 R14: ffff88813663b1c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f28327c0fc8 CR3: 000000011bb94000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 smp_call_function_many_cond+0xd4b/0x12d0
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x6b1/0x12d0
 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+0x1fa/0x8c0
 mpage_submit_folio+0x86/0x2b0
 ext4_do_writepages+0x1d43/0x4610
 ext4_writepages+0x205/0x350
 do_writepages+0x32e/0x550
 __writeback_single_inode+0x145/0xff0
 writeback_sb_inodes+0x6c7/0x1010
 __writeback_inodes_wb+0x111/0x240
 wb_writeback+0x44f/0xaf0
 wb_workfn+0xaef/0xef0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
