syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=b6ec/1/0x4000000000000000 softirq=41434/41435 fqs=1
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9995/1:b..l
rcu: 	(detected by 1, t=10506 jiffies, g=30333, q=246 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10362 Comm: syz.1.1090 Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x60/0xc0 kernel/rcu/tree.c:737
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 75 5c 48 03 1c ed 80 4b a6 8d 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 0f b6 14 02 <48> 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 24 8b 03 c1 e8 02
RSP: 0018:ffffc90000007cd0 EFLAGS: 00000802
RAX: dffffc0000000000 RBX: ffff8880b8638128 RCX: ffffffff8169adde
RDX: 0000000000000000 RSI: ffffffff8bd1b300 RDI: ffffffff8da64b80
RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff20beb31
R10: ffffffff905f598f R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f49c2bf66c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe153a88c8 CR3: 000000005e03e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 trace_lock_acquire+0x14a/0x1d0 include/trace/events/lock.h:24
 lock_acquire+0x2f/0xb0 kernel/locking/lockdep.c:5796
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 advance_sched+0x67f/0xc60 net/sched/sch_taprio.c:985
 __run_hrtimer kernel/time/hrtimer.c:1691 [inline]
 __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1755
 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1817
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire.part.0+0x155/0x380 kernel/locking/lockdep.c:5790
Code: b8 ff ff ff ff 65 0f c1 05 70 de 97 7e 83 f8 01 0f 85 d0 01 00 00 9c 58 f6 c4 02 0f 85 e5 01 00 00 48 85 ed 0f 85 b6 01 00 00 <48> b8 00 00 00 00 00 fc ff df 48 01 c3 48 c7 03 00 00 00 00 48 c7
RSP: 0018:ffffc900190d70c8 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 1ffff9200321ae1a RCX: 0000000000000001
RDX: 0000000000000001 RSI: ffffffff8b6cd2a0 RDI: ffffffff8bd1b380
RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2dc5d88
R10: ffffffff96e2ec47 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8e1b8340 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 page_ext_get+0x3a/0x310 mm/page_ext.c:525
 __set_page_owner+0x96/0x560 mm/page_owner.c:322
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1541
 prep_new_page mm/page_alloc.c:1549 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3459
 __alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4735
 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
 vm_area_alloc_pages mm/vmalloc.c:3568 [inline]
 __vmalloc_area_node mm/vmalloc.c:3646 [inline]
 __vmalloc_node_range_noprof+0x724/0x15a0 mm/vmalloc.c:3828
 vmalloc_user_noprof+0x6b/0x90 mm/vmalloc.c:3982
 vb2_vmalloc_alloc+0x11e/0x3d0 drivers/media/common/videobuf2/videobuf2-vmalloc.c:47
 __vb2_buf_mem_alloc drivers/media/common/videobuf2/videobuf2-core.c:242 [inline]
 __vb2_queue_alloc+0x896/0x1230 drivers/media/common/videobuf2/videobuf2-core.c:523
 vb2_core_reqbufs+0xa73/0xfb0 drivers/media/common/videobuf2/videobuf2-core.c:964
 vb2_ioctl_reqbufs+0x299/0x430 drivers/media/common/videobuf2/videobuf2-v4l2.c:1036
 vidioc_reqbufs+0x86/0x100 drivers/media/test-drivers/vivid/vivid-core.c:707
 v4l_reqbufs+0x14c/0x1e0 drivers/media/v4l2-core/v4l2-ioctl.c:2156
 __video_do_ioctl+0xaf0/0xf00 drivers/media/v4l2-core/v4l2-ioctl.c:3119
 video_usercopy+0x4ce/0x1600 drivers/media/v4l2-core/v4l2-ioctl.c:3460
 v4l2_ioctl+0x1ba/0x250 drivers/media/v4l2-core/v4l2-dev.c:364
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18f/0x220 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f49c1d7e719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f49c2bf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f49c1f35f80 RCX: 00007f49c1d7e719
RDX: 0000000020000000 RSI: 00000000c0145608 RDI: 0000000000000004
RBP: 00007f49c1df1616 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f49c1f35f80 R15: 00007fffdb7ed998
 </TASK>
task:udevd           state:R  running task     stack:26320 pid:9995  tgid:9995  ppid:5199   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0xe55/0x5740 kernel/sched/core.c:6690
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7012
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:lock_acquire.part.0+0x155/0x380 kernel/locking/lockdep.c:5790
Code: b8 ff ff ff ff 65 0f c1 05 70 de 97 7e 83 f8 01 0f 85 d0 01 00 00 9c 58 f6 c4 02 0f 85 e5 01 00 00 48 85 ed 0f 85 b6 01 00 00 <48> b8 00 00 00 00 00 fc ff df 48 01 c3 48 c7 03 00 00 00 00 48 c7
RSP: 0018:ffffc9000361f958 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 1ffff920006c3f2c RCX: 0000000000000001
RDX: 0000000000000001 RSI: ffffffff8b6cd2a0 RDI: ffffffff8bd1b380
RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2dc5d88
R10: ffffffff96e2ec47 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8e1b8340 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 dput.part.0+0x4c/0x9b0 fs/dcache.c:850
 dput+0x1f/0x30 fs/dcache.c:847
 path_put fs/namei.c:568 [inline]
 terminate_walk+0x1a8/0x680 fs/namei.c:692
 path_openat+0x1e53/0x2d60 fs/namei.c:3934
 do_filp_open+0x1dc/0x430 fs/namei.c:3960
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_openat fs/open.c:1446 [inline]
 __se_sys_openat fs/open.c:1441 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1441
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f83347169a4
RSP: 002b:00007ffe153af810 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00005654280c9470 RCX: 00007f83347169a4
RDX: 0000000000080000 RSI: 00007ffe153af928 RDI: 00000000ffffff9c
RBP: 00007ffe153af928 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000080000
R13: 00005654280c9560 R14: 00007ffe153af928 R15: 00005654280f4ec0
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g30333 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:27504 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0xe55/0x5740 kernel/sched/core.c:6690
 __schedule_loop kernel/sched/core.c:6767 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6782
 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2615
 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045
 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 35 Comm: kworker/u8:2 Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x458/0x1300 kernel/smp.c:884
Code: 0c 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 8a 1b 0c 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 a4 0c 00 00 8b 43 08 31
RSP: 0018:ffffc90000ab7998 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8646b80 RCX: ffffffff81815ffc
RDX: ffff88801deda440 RSI: ffffffff81815fd6 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170c8d71
R13: 0000000000000001 R14: ffff8880b8646b88 R15: ffff8880b8740100
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000040 CR3: 000000000df7c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1051
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2085 [inline]
 text_poke_bp_batch+0x22b/0x760 arch/x86/kernel/alternative.c:2295
 text_poke_flush arch/x86/kernel/alternative.c:2486 [inline]
 text_poke_flush arch/x86/kernel/alternative.c:2483 [inline]
 text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2493
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x1d7/0x400 kernel/jump_label.c:920
 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate mm/kfence/core.c:849 [inline]
 toggle_allocation_gate+0xfc/0x260 mm/kfence/core.c:841
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>