syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8876/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=34573, q=868 ncpus=2)
task:syz.3.813       state:R  running task     stack:26760 pid:8876  tgid:8875  ppid:5609   task_flags:0x400040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x10e9/0x6820 kernel/sched/core.c:7189
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline]
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x19e/0x310 kernel/locking/lockdep.c:5893
Code: ff 65 0f c1 05 9b 6e 26 12 83 f8 01 0f 85 28 01 00 00 9c 58 f6 c4 02 0f 85 13 01 00 00 41 f7 c6 00 02 00 00 0f 85 c0 00 00 00 <48> 8b 44 24 10 65 48 2b 05 ed 26 26 12 0f 85 4e 01 00 00 48 83 c4
RSP: 0018:ffffc9000377eea8 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e7e54e0 RCX: ffffc9000377eeb4
RDX: 0000000000000001 RSI: ffffffff8defa991 RDI: ffffffff8c1c3600
RBP: ffffffff81b7c1ae R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000000aeda R12: ffff888030622500
R13: ffffc9000377efb0 R14: 0000000000000202 R15: 0000000000000002
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x3c3/0x2090 arch/x86/kernel/unwind_orc.c:495
 __unwind_start+0x3d1/0x7f0 arch/x86/kernel/unwind_orc.c:787
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x162/0x1e0 mm/page_owner.c:165
 __set_page_owner+0x8c/0x540 mm/page_owner.c:341
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226
 alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490
 folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2509
 vma_alloc_folio_noprof+0xed/0x1d0 mm/mempolicy.c:2544
 folio_prealloc mm/memory.c:1191 [inline]
 alloc_anon_folio mm/memory.c:5282 [inline]
 do_anonymous_page+0xb46/0x2050 mm/memory.c:5376
 do_pte_missing mm/memory.c:4548 [inline]
 handle_pte_fault mm/memory.c:6411 [inline]
 __handle_mm_fault+0x1d2c/0x2a00 mm/memory.c:6549
 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x1178/0x32a0 mm/gup.c:1428
 __get_user_pages_locked mm/gup.c:1692 [inline]
 faultin_page_range+0x1f1/0x9e0 mm/gup.c:1912
 madvise_populate mm/madvise.c:969 [inline]
 madvise_do_behavior+0x354/0x510 mm/madvise.c:1927
 do_madvise+0x195/0x240 mm/madvise.c:2022
 __do_sys_madvise mm/madvise.c:2031 [inline]
 __se_sys_madvise mm/madvise.c:2029 [inline]
 __x64_sys_madvise+0xa9/0x110 mm/madvise.c:2029
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f059439cdd9
RSP: 002b:00007f05952af028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f0594615fa0 RCX: 00007f059439cdd9
RDX: 0000000000000017 RSI: 0000000000800000 RDI: 00002000000ec000
RBP: 00007f0594432d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0594616038 R14: 00007f0594615fa0 R15: 00007ffd762dd078
 </TASK>
rcu: rcu_preempt kthread starved for 10490 jiffies! g34573 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:28872 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x10e9/0x6820 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7283
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 8877 Comm: syz.2.812 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x58e/0x1700 kernel/smp.c:892
Code: 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 79 7c 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 ff 83 e0 01 41
RSP: 0018:ffffc900104bf628 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000f879000
RDX: 0000000000080000 RSI: ffffffff81fc0f67 RDI: ffff8880324c2500
RBP: ffff8880b8443320 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed1017088665 R14: 0000000000000001 R15: ffff8880b853c5c0
FS:  00007f55d64ba6c0(0000) GS:ffff888124476000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f55d6497fa8 CR3: 0000000035d92000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
 invalidate_bdev+0x77/0xb0 block/bdev.c:100
 loop_set_status+0x19c/0xb50 drivers/block/loop.c:1246
 loop_set_status_old+0x163/0x1d0 drivers/block/loop.c:1362
 lo_ioctl+0xd6c/0x1bc0 drivers/block/loop.c:1551
 blkdev_ioctl+0x5ad/0x6f0 block/ioctl.c:797
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f55d559cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f55d64ba028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f55d5816090 RCX: 00007f55d559cdd9
RDX: 0000200000000280 RSI: 0000000000004c02 RDI: 0000000000000004
RBP: 00007f55d5632d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f55d5816128 R14: 00007f55d5816090 R15: 00007ffc30d7cf08
 </TASK>