rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5855/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=9413, q=614 ncpus=2)
task:syz.1.2 state:R running task stack:22888 pid:5855 ppid:5773 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6701
preempt_schedule_notrace+0xdd/0x110 kernel/sched/core.c:6961
preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:46
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x405/0x420 kernel/locking/lockdep.c:5725
rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
rcu_read_lock include/linux/rcupdate.h:786 [inline]
xa_load+0x80/0x2e0 lib/xarray.c:1459
__readahead_folio include/linux/pagemap.h:1364 [inline]
readahead_folio include/linux/pagemap.h:1397 [inline]
ext4_mpage_readpages+0x504/0x2ae0 fs/ext4/readpage.c:249
read_pages+0x18b/0x860 mm/readahead.c:160
page_cache_ra_unbounded+0x661/0x740 mm/readahead.c:269
do_async_mmap_readahead mm/filemap.c:3274 [inline]
filemap_fault+0x569/0x1540 mm/filemap.c:3328
__do_fault+0x13b/0x4d0 mm/memory.c:4244
do_read_fault mm/memory.c:4638 [inline]
do_fault mm/memory.c:4775 [inline]
do_pte_missing mm/memory.c:3689 [inline]
handle_pte_fault mm/memory.c:5047 [inline]
__handle_mm_fault mm/memory.c:5188 [inline]
handle_mm_fault+0x3945/0x4a50 mm/memory.c:5353
faultin_page mm/gup.c:868 [inline]
__get_user_pages+0x604/0x1580 mm/gup.c:1167
__get_user_pages_locked mm/gup.c:1431 [inline]
get_dump_page+0x10c/0x200 mm/gup.c:1939
dump_user_range+0x127/0x840 fs/coredump.c:983
elf_core_dump+0x320e/0x37c0 fs/binfmt_elf.c:2184
do_coredump+0x1791/0x24a0 fs/coredump.c:834
get_signal+0x10da/0x1390 kernel/signal.c:2897
arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
irqentry_exit_to_user_mode+0x9/0x30 kernel/entry/common.c:315
exc_page_fault+0x8c/0x100 arch/x86/mm/fault.c:1519
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7fe910a53bd7
RSP: 002b:00007fe911ad0120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007fe910b9e159
RDX: 00007fe911ad0140 RSI: 00007fe911ad0270 RDI: 000000000000000b
RBP: 00007fe910c3503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fe910e26038 R14: 00007fe910e25fa0 R15: 00007fff58d49858
rcu: rcu_preempt kthread starved for 727 jiffies! g9413 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:27848 pid:17 ppid:2 flags:0x00004000
Call Trace:
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
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xd85/0x1190 kernel/smp.c:855
Code: 45 8b 34 24 44 89 f6 83 e6 01 31 ff e8 14 01 0b 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 4f fd 0a 00 eb 38 f3 90 <42> 0f b6 04 33 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 33 fd
RSP: 0018:ffffc90000117780 EFLAGS: 00000293
RAX: ffffffff817c853d RBX: 1ffff110171c87a5 RCX: ffff88801b65da00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000117900 R08: ffffffff911ef507 R09: 1ffffffff223dea0
R10: dffffc0000000000 R11: fffffbfff223dea1 R12: ffff8880b8e43d28
R13: ffff8880b8f3d380 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa5aa52ae80 CR3: 000000000cf32000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
text_poke_bp_batch+0x31e/0x980 arch/x86/kernel/alternative.c:2432
text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
static_key_enable+0x1a/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xa8/0x260 mm/kfence/core.c:847
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