rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=aa34/1/0x4000000000000000 softirq=32378/32379 fqs=1
rcu: (detected by 1, t=10502 jiffies, g=37305, q=2774 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5625 Comm: udevd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x3b/0xb0 kernel/rcu/tree.c:753
Code: e8 6a 3b 37 0a 89 c3 83 f8 08 73 66 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 97 74 8e 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 9b 32 8b 00 48 c7 c3 18 9b 95 93 49 03 1e 48 89
RSP: 0018:ffffc90000007da0 EFLAGS: 00000046
RAX: 1ffffffff1ce92fa RBX: 0000000000000000 RCX: 8000000001000001
RDX: 8000000001000001 RSI: ffffffff8c6d8d60 RDI: ffffffff8c6d8d20
RBP: ffff88802bc74300 R08: 0000000001000001 R09: 1ffffffff20f490f
R10: dffffc0000000000 R11: fffffbfff20f4910 R12: 0000000000000000
R13: ffffffff89ebfe20 R14: ffffffff8e7497d0 R15: dffffc0000000000
FS: 00007f55ce94c880(0000) GS:ffff888124cda000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f55ce948000 CR3: 0000000079f2a000 CR4: 00000000003526f0
Call Trace:
trace_hrtimer_expire_entry include/trace/events/timer.h:261 [inline]
__run_hrtimer kernel/time/hrtimer.c:2065 [inline]
__hrtimer_run_queues+0x326/0xa10 kernel/time/hrtimer.c:2125
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2244
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__sanitizer_cov_trace_pc+0x75/0x80 kernel/kcov.c:231
Code: 10 17 00 00 83 fa 02 75 21 48 8b 91 18 17 00 00 48 8b 32 48 8d 7e 01 8b 89 14 17 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 cc cc cc cc cc 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003e07698 EFLAGS: 00000293
RAX: ffffffff821347de RBX: 0000000000000000 RCX: ffff888012683e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003e07a30 R08: ffffea0001037d87 R09: 1ffffd4000206fb0
R10: dffffc0000000000 R11: fffff94000206fb1 R12: dffffc0000000000
R13: ffffea00010f6b40 R14: ffffc90003e07880 R15: 0000000000000000
shmem_undo_range+0x3ee/0x15d0 mm/shmem.c:1156
shmem_truncate_range mm/shmem.c:1289 [inline]
shmem_evict_inode+0x247/0xae0 mm/shmem.c:1420
evict+0x624/0xb50 fs/inode.c:822
dentry_kill+0x1b9/0x880 fs/dcache.c:826
finish_dput+0x1a/0x260 fs/dcache.c:1001
__fput+0x675/0xa50 fs/file_table.c:520
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f55ce2a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff7791fd00 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f55ce94c880 RCX: 00007f55ce2a7407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007f55ce94c6e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
R13: 0000557cd10c3190 R14: 0000000000000008 R15: 0000557cd10d2f10
rcu: rcu_preempt kthread starved for 10462 jiffies! g37305 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5521 [inline]
__schedule+0x1b57/0x5bc0 kernel/sched/core.c:7272
__schedule_loop kernel/sched/core.c:7349 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7364
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 1158 Comm: kworker/u8:9 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:363 [inline]
RIP: 0010:csd_lock kernel/smp.c:396 [inline]
RIP: 0010:smp_call_function_many_cond+0x61e/0x1500 kernel/smp.c:944
Code: b6 04 04 84 c0 0f 85 d5 03 00 00 44 8b 3b 44 89 fe 83 e6 01 31 ff e8 51 51 0c 00 41 83 e7 01 75 07 e8 46 4c 0c 00 eb 3f f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 0f f7 03 01
RSP: 0018:ffffc900051fe120 EFLAGS: 00000293
RAX: ffffffff81bb734e RBX: ffff8880b8643808 RCX: ffff8880289d5dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900051fe270 R08: ffff8880289d735f R09: 1ffff1100513ae6b
R10: dffffc0000000000 R11: ffffffff8179db70 R12: 1ffff110170c8701
R13: 0000000000000000 R14: ffff8880b8643800 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff3e6102d8 CR3: 000000005aeca000 CR4: 00000000003526f0
Call Trace:
__flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x8ff/0x1090 arch/x86/mm/tlb.c:1435
flush_tlb_page arch/x86/include/asm/tlbflush.h:352 [inline]
ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:104
page_vma_mkclean_one+0x4b9/0x840 mm/rmap.c:1142
page_mkclean_one+0x20c/0x2e0 mm/rmap.c:1190
__rmap_walk_file+0x4cd/0x6a0 mm/rmap.c:3116
rmap_walk mm/rmap.c:3160 [inline]
folio_mkclean+0x2d5/0x3f0 mm/rmap.c:1222
folio_clear_dirty_for_io+0x190/0x820 mm/page-writeback.c:2903
mpage_submit_folio+0x83/0x2a0 fs/ext4/inode.c:2075
mpage_process_page_bufs+0x6bd/0x8a0 fs/ext4/inode.c:2201
mpage_prepare_extent_to_map+0xf92/0x1890 fs/ext4/inode.c:2743
ext4_do_writepages+0xb8a/0x4770 fs/ext4/inode.c:2884
ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3032
do_writepages+0x338/0x560 mm/page-writeback.c:2560
__writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1788
writeback_sb_inodes+0x9de/0x1b00 fs/fs-writeback.c:2099
__writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2175
wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2286
wb_check_old_data_flush fs/fs-writeback.c:2390 [inline]
wb_do_writeback fs/fs-writeback.c:2469 [inline]
wb_workfn+0xc92/0x10f0 fs/fs-writeback.c:2497
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245