rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P60/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=10113, q=583031 ncpus=2)
task:kworker/u4:4    state:R  running task     stack:25256 pid:60    ppid:2      flags:0x00004000
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:441
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5760
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900015b7660 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 6f1281b77f6e3200
RDX: 0000000000000000 RSI: ffffffff8acade60 RDI: ffffffff8b1d3ba0
RBP: ffffc900015b7768 R08: dffffc0000000000 R09: 1ffffffff223d6a0
R10: dffffc0000000000 R11: fffffbfff223d6a1 R12: 1ffff920002b6ed8
R13: ffffffff8d1320e0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 folio_memcg_lock+0xa2/0x320 mm/memcontrol.c:2150
 __folio_end_writeback+0x155/0xe10 mm/page-writeback.c:2971
 folio_end_writeback+0x150/0x690 mm/filemap.c:1641
 ext4_finish_bio+0x5e2/0xb00 fs/ext4/page-io.c:144
 ext4_release_io_end+0xef/0x2b0 fs/ext4/page-io.c:159
 ext4_end_io_end fs/ext4/page-io.c:204 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:269 [inline]
 ext4_end_io_rsv_work+0x4db/0x640 fs/ext4/page-io.c:283
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: rcu_preempt kthread starved for 10533 jiffies! g10113 f0x2 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:27848 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6558 Comm: syz-executor308 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:__kasan_check_read+0xc/0x20 mm/kasan/shadow.c:31
Code: c7 f0 f2 a4 8c 4c 89 e6 eb 0a 48 c7 c7 81 77 86 8c 48 89 de e8 55 aa a5 08 31 ed eb d4 cc f3 0f 1e fa 89 f6 48 8b 0c 24 31 d2 <e9> ff ea ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f
RSP: 0018:ffffc900050878b8 EFLAGS: 00000046
RAX: 0000000000000030 RBX: ffff88807f090000 RCX: ffffffff81695584
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911eb530
RBP: 0000000000000003 R08: dffffc0000000000 R09: 1ffffffff223d6a6
R10: dffffc0000000000 R11: fffffbfff223d6a7 R12: 0000000000000008
R13: dffffc0000000000 R14: ffff88807f090ae8 R15: 00000000000001ad
FS:  00007f08f8a8e6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001840 CR3: 0000000074aac000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hlock_class kernel/locking/lockdep.c:228 [inline]
 mark_lock+0x94/0x320 kernel/locking/lockdep.c:4656
 mark_usage kernel/locking/lockdep.c:4579 [inline]
 __lock_acquire+0x10fd/0x7d80 kernel/locking/lockdep.c:5091
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5756
 __might_fault+0xc6/0x120 mm/memory.c:5968
 _copy_from_user+0x2a/0xe0 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:183 [inline]
 restore_sigcontext arch/x86/kernel/signal_64.c:59 [inline]
 __ia32_sys_rt_sigreturn+0x2e1/0x850 arch/x86/kernel/signal_64.c:266
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f08f8a9c599
Code: 3c 01 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 0c 25
RSP: 002b:00007f08f8a8dbc0 EFLAGS: 00000202 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f08f8b60b68 RCX: 00007f08f8a9c599
RDX: 00007f08f8a8dbc0 RSI: 00007f08f8a8dcf0 RDI: 0000000000000021
RBP: 00007f08f8b60b60 R08: 00007f08f8a8ecdc R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007f08f8b60b6c
R13: 0000000000000000 R14: 00007ffdae7ed200 R15: 00007ffdae7ed2e8
 </TASK>
sched: RT throttling activated