syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8009/1:b..l P5826/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=29053, q=427 ncpus=2)
task:syz-executor    state:R  running task     stack:20544 pid:5826  tgid:5826  ppid:5820   flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 preempt_schedule_notrace+0x100/0x140 kernel/sched/core.c:7028
 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x7e/0xb0 kernel/rcu/tree.c:738
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xe3/0x550 kernel/locking/lockdep.c:5820
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 page_ext_get+0x3d/0x2a0 mm/page_ext.c:525
 __reset_page_owner+0x30/0x430 mm/page_owner.c:290
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xd3f/0x1010 mm/page_alloc.c:2659
 discard_slab mm/slub.c:2688 [inline]
 __put_partials+0x160/0x1c0 mm/slub.c:3157
 put_cpu_partial+0x17c/0x250 mm/slub.c:3232
 __slab_free+0x290/0x380 mm/slub.c:4483
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4119 [inline]
 slab_alloc_node mm/slub.c:4168 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4175
 getname_flags+0xb7/0x540 fs/namei.c:139
 getname fs/namei.c:223 [inline]
 __do_sys_unlink fs/namei.c:4635 [inline]
 __se_sys_unlink fs/namei.c:4633 [inline]
 __x64_sys_unlink+0x3a/0x50 fs/namei.c:4633
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f27fbf852d7
RSP: 002b:00007ffd11f334c8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f27fbf852d7
RDX: 00007ffd11f334f0 RSI: 00007ffd11f33580 RDI: 00007ffd11f33580
RBP: 00007ffd11f33580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd11f34600
R13: 00007f27fc001894 R14: 00007ffd11f34640 R15: 0000000000000072
 </TASK>
task:syz-executor    state:R  running task     stack:20544 pid:8009  tgid:8009  ppid:8000   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7078
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:jhash2 include/linux/jhash.h:129 [inline]
RIP: 0010:hash_stack lib/stackdepot.c:514 [inline]
RIP: 0010:stack_depot_save_flags+0x99/0x940 lib/stackdepot.c:614
Code: 89 f0 4c 8b 44 24 08 4c 89 c2 03 02 03 5a 04 44 03 72 08 44 89 f7 c1 c7 04 44 29 f0 31 c7 41 01 de 29 fb 89 fd c1 c5 06 31 dd <44> 01 f7 89 e9 c1 c1 08 41 29 ee 44 31 f1 01 fd 29 cf 89 c8 c1 c0
RSP: 0018:ffffc900033c7510 EFLAGS: 00000282
RAX: 0000000095a5fc65 RBX: 0000000002c17be9 RCX: 0000000059f263af
RDX: ffffc900033c7614 RSI: 0000000000000009 RDI: 00000000073cf1a9
RBP: 00000000cdfd11a8 R08: ffffc900033c75c0 R09: 000000000000000f
R10: dffffc0000000000 R11: fffffbfff2032f9f R12: dffffc0000000000
R13: 1ffff92000678eb4 R14: 00000000d327fe6e R15: 1ffff11005444830
 save_stack+0x109/0x1f0 mm/page_owner.c:157
 __reset_page_owner+0x76/0x430 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xd3f/0x1010 mm/page_alloc.c:2659
 discard_slab mm/slub.c:2688 [inline]
 __put_partials+0x160/0x1c0 mm/slub.c:3157
 put_cpu_partial+0x17c/0x250 mm/slub.c:3232
 __slab_free+0x290/0x380 mm/slub.c:4483
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x23/0xb0 mm/kasan/common.c:385
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4298 [inline]
 __kmalloc_noprof+0x285/0x4c0 mm/slub.c:4310
 kmalloc_noprof include/linux/slab.h:905 [inline]
 tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251
 tomoyo_mount_acl security/tomoyo/mount.c:105 [inline]
 tomoyo_mount_permission+0x3bf/0xb80 security/tomoyo/mount.c:237
 security_sb_mount+0xe0/0x2f0 security/security.c:1564
 path_mount+0xb9/0xfa0 fs/namespace.c:3776
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe3ecf874ca
RSP: 002b:00007ffdd1f3b718 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe3ed001e6b RCX: 00007fe3ecf874ca
RDX: 00007fe3ed00ebc7 RSI: 00007fe3ed001e6b RDI: 00007fe3ed00ebc7
RBP: 00007fe3ed002063 R08: 0000000000000000 R09: 00007fe3ed176738
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe3ecfe41c8
R13: 00007fe3ecfe41a8 R14: 0000000000000009 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10366 jiffies! g29053 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:25880 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111