rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9544/1:b..l P9500/1:b..l
(detected by 0, t=10502 jiffies, g=39909, q=21 ncpus=2)
task:syz.4.1485 state:R running task stack:23808 pid:9500 ppid:4270 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5710
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc9000cf0ec80 EFLAGS: 00000206
RAX: 3612a480f0d53300 RBX: ffff888066c8d940 RCX: 3612a480f0d53300
RDX: ffff888066c8d940 RSI: ffffffff8a8c15a0 RDI: ffffffff8adef6a0
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff215bc49
R10: fffffbfff215bc49 R11: 1ffffffff215bc48 R12: 0000000000000003
R13: 0000000000000246 R14: ffffffff8cb53898 R15: ffff888066c8e498
lock_is_held include/linux/lockdep.h:283 [inline]
task_css include/linux/cgroup.h:509 [inline]
blkcg_css+0xcb/0x1c0 block/blk-cgroup.c:77
blk_cgroup_congested+0xba/0x220 block/blk-cgroup.c:2013
__cgroup_throttle_swaprate+0x6d/0x1a0 mm/swapfile.c:3671
cgroup_throttle_swaprate include/linux/swap.h:662 [inline]
folio_throttle_swaprate include/linux/swap.h:671 [inline]
shmem_add_to_page_cache+0x9c1/0x1c00 mm/shmem.c:717
shmem_get_folio_gfp+0x158b/0x3400 mm/shmem.c:1971
shmem_get_folio mm/shmem.c:2072 [inline]
shmem_write_begin+0xee/0x3f0 mm/shmem.c:2556
generic_perform_write+0x2db/0x560 mm/filemap.c:3846
__generic_file_write_iter+0x172/0x430 mm/filemap.c:3974
generic_file_write_iter+0xab/0x2e0 mm/filemap.c:4006
__kernel_write_iter+0x26d/0x630 fs/read_write.c:517
dump_emit_page fs/coredump.c:950 [inline]
dump_user_range+0x3ea/0x7f0 fs/coredump.c:977
elf_core_dump+0x2f77/0x3490 fs/binfmt_elf.c:2354
do_coredump+0x15ff/0x22b0 fs/coredump.c:824
get_signal+0x10aa/0x1350 kernel/signal.c:2857
arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1490
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0xbfee0149
RSP: 002b:00002000000002d8 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f5cc9bb5fa0 RCX: 00007f5cc998ebe9
RDX: 0000200000000580 RSI: 00002000000002d0 RDI: 0000000000000000
RBP: 00007f5cc9a11e19 R08: 00002000000006c0 R09: 00002000000006c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5cc9bb6038 R14: 00007f5cc9bb5fa0 R15: 00007ffc042b1748
task:syz.1.1497 state:R running task stack:26240 pid:9544 ppid:4261 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
filemap_map_pmd mm/filemap.c:3361 [inline]
filemap_map_pages+0x50d/0x10d0 mm/filemap.c:3449
do_fault_around mm/memory.c:4600 [inline]
do_read_fault mm/memory.c:4626 [inline]
do_fault mm/memory.c:4760 [inline]
handle_pte_fault mm/memory.c:5031 [inline]
__handle_mm_fault mm/memory.c:5173 [inline]
handle_mm_fault+0x2889/0x3e70 mm/memory.c:5294
do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
handle_page_fault arch/x86/mm/fault.c:1431 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f960e06ee90
RSP: 002b:00007fff4298fb50 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00007f960eee5720 RCX: 000000110c230000
RDX: 0000000000000861 RSI: ffffffffbfffffff RDI: 0000000000000000
RBP: ffffffff8818a861 R08: 00007f960e3b6038 R09: 00007f960e3a2000
R10: 00007f960dbff008 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8818a10b R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10568 jiffies! g39909 f0x0 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:27904 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 b7 91 b0 f7 e9 4c ff ff ff e8 2d 08 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d b7 55 66 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c807d88 EFLAGS: 000002c6
RAX: 78b922ed44499c00 RBX: ffffffff8a204e37 RCX: 78b922ed44499c00
RDX: 0000000000000001 RSI: ffffffff8a8c0420 RDI: ffffffff8adef6a0
RBP: ffffffff8c807ec0 R08: dffffc0000000000 R09: ffffed10171c6af6
R10: ffffed10171c6af6 R11: 1ffff110171c6af5 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8c8bc680 R15: 1ffffffff1c3ead6
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f86297f5f40 CR3: 00000000688e1000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1fc/0x570 kernel/sched/idle.c:303
cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
rest_init+0x2dc/0x300 init/main.c:733
arch_call_rest_init+0xa/0xa init/main.c:893
start_kernel+0x490/0x539 init/main.c:1140
secondary_startup_64_no_verify+0xcf/0xdb