[syzbot] [bpf?] INFO: rcu detected stall in security_file_ioctl (9)

[syzbot] [bpf?] INFO: rcu detected stall in security_file_ioctl (9)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    f1b785f4c787 Merge tag 'for_linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148914c0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=327b6119dd928cbc
dashboard link: https://syzkaller.appspot.com/bug?extid=b6f8640465bdf47ca708
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2eb65d2a03c1/disk-f1b785f4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70c538f32a8e/vmlinux-f1b785f4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/79fc36f9a44b/bzImage-f1b785f4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6f8640465bdf47ca708@syzkaller.appspotmail.com

bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P14575/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=63037, q=305 ncpus=2)
task:syz-executor    state:R  running task     stack:26048 pid:14575 tgid:14575 ppid:5814   flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0xe55/0x5740 kernel/sched/core.c:6693
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7015
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:61 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:130 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x4d/0x1a0 mm/kasan/generic.c:189
Code: ff ff ff ff ff 7f ff ff 48 39 f8 0f 83 b3 00 00 00 4c 8d 54 37 ff 48 89 fd 48 b8 00 00 00 00 00 fc ff df 4d 89 d1 48 c1 ed 03 <49> c1 e9 03 48 01 c5 49 01 c1 48 89 e8 49 8d 59 01 48 89 da 48 29
RSP: 0018:ffffc90003ab7698 EFLAGS: 00000a02
RAX: dffffc0000000000 RBX: ffffc90003ab7728 RCX: ffffffff813d6ebe
RDX: 0000000000000001 RSI: 0000000000000060 RDI: ffffc90003ab7728
RBP: 1ffff92000756ee5 R08: 0000000000000001 R09: ffffc90003ab7787
R10: ffffc90003ab7787 R11: 0000000000000000 R12: 0000000000000000
R13: ffffc90003ab77e8 R14: ffffc90003ab7728 R15: ffffc90003ab7750
 __asan_memset+0x23/0x50 mm/kasan/shadow.c:84
 __unwind_start+0x2e/0x7f0 arch/x86/kernel/unwind_orc.c:688
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0x74/0x100 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
 save_stack+0x162/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x8d/0x400 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1112 [inline]
 free_unref_page+0x5f4/0xdc0 mm/page_alloc.c:2642
 __put_partials+0x14c/0x170 mm/slub.c:3145
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:247 [inline]
 slab_post_alloc_hook mm/slub.c:4085 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 __do_kmalloc_node mm/slub.c:4263 [inline]
 __kmalloc_noprof+0x199/0x400 mm/slub.c:4276
 kmalloc_noprof include/linux/slab.h:882 [inline]
 kzalloc_noprof include/linux/slab.h:1014 [inline]
 tomoyo_encode2+0x100/0x3e0 security/tomoyo/realpath.c:45
 tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x19d/0x720 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x245/0x590 security/tomoyo/file.c:723
 security_file_ioctl+0x9b/0x240 security/security.c:2910
 __do_sys_ioctl fs/ioctl.c:901 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0xbb/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: 0033:0x7f496817e31b
RSP: 002b:00007fff5d2dd2a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007f496817e31b
RDX: 0000000000040000 RSI: ffffffff80086301 RDI: 00000000000000d8
RBP: 00007f4968336018 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10538 jiffies! g63037 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:25616 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:6693
 __schedule_loop kernel/sched/core.c:6770 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6785
 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: 24 Comm: ksoftirqd/1 Not tainted 6.12.0-rc7-syzkaller-00042-gf1b785f4c787 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:80 [inline]
RIP: 0010:__orc_find+0x70/0xf0 arch/x86/kernel/unwind_orc.c:102
Code: ec 72 4e 4c 89 e2 48 29 ea 48 89 d6 48 c1 ea 3f 48 c1 fe 02 48 01 f2 48 d1 fa 48 8d 5c 95 00 48 89 da 48 c1 ea 03 0f b6 34 0a <48> 89 da 83 e2 07 83 c2 03 40 38 f2 7c 05 40 84 f6 75 4b 48 63 13
RSP: 0018:ffffc900001e6958 EFLAGS: 00000a02
RAX: ffffffff918e78be RBX: ffffffff90d866c8 RCX: dffffc0000000000
RDX: 1ffffffff21b0cd9 RSI: 0000000000000000 RDI: ffffffff90d866c4
RBP: ffffffff90d866c4 R08: ffffffff918e78f4 R09: ffffffff918e7b74
R10: ffffc900001e6a08 R11: 000000000008f938 R12: ffffffff90d866d0
R13: ffffffff89f9389f R14: ffffffff90d866c4 R15: ffffffff90d866c4
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557ffcb06ca3 CR3: 000000007a814000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
 unwind_next_frame+0x2be/0x20c0 arch/x86/kernel/unwind_orc.c:494
 arch_stack_walk+0x95/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:2342 [inline]
 slab_free mm/slub.c:4579 [inline]
 kmem_cache_free+0x152/0x4b0 mm/slub.c:4681
 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1148
 __kfree_skb net/core/skbuff.c:1205 [inline]
 sk_skb_reason_drop+0x136/0x1a0 net/core/skbuff.c:1242
 kfree_skb_reason include/linux/skbuff.h:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [inline]
 ip6_mc_input+0x7af/0xfd0 net/ipv6/ip6_input.c:587
 dst_input include/net/dst.h:460 [inline]
 dst_input include/net/dst.h:458 [inline]
 ip6_rcv_finish+0x3a2/0x5b0 net/ipv6/ip6_input.c:79
 ip_sabotage_in+0x21b/0x290 net/bridge/br_netfilter_hooks.c:1018
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626
 nf_hook.constprop.0+0x42e/0x750 include/linux/netfilter.h:269
 NF_HOOK include/linux/netfilter.h:312 [inline]
 ipv6_rcv+0xa4/0x680 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core+0x12e/0x1e0 net/core/dev.c:5670
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5783
 netif_receive_skb_internal net/core/dev.c:5869 [inline]
 netif_receive_skb+0x13f/0x7b0 net/core/dev.c:5928
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70
 br_handle_frame_finish+0xdcf/0x1c80 net/bridge/br_input.c:221
 br_nf_hook_thresh+0x303/0x410 net/bridge/br_netfilter_hooks.c:1195
 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x3ce/0x8c0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:533
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:277 [inline]
 br_handle_frame+0x9eb/0x1490 net/bridge/br_input.c:424
 __netif_receive_skb_core.constprop.0+0xa3d/0x4330 net/core/dev.c:5564
 __netif_receive_skb_one_core+0xb1/0x1e0 net/core/dev.c:5668
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5783
 process_backlog+0x443/0x15f0 net/core/dev.c:6115
 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6779
 napi_poll net/core/dev.c:6848 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6970
 handle_softirqs+0x213/0x8f0 kernel/softirq.c:554
 run_ksoftirqd kernel/softirq.c:927 [inline]
 run_ksoftirqd+0x3a/0x60 kernel/softirq.c:919
 smpboot_thread_fn+0x661/0xa30 kernel/smpboot.c:164
 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>
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
net_ratelimit: 34076 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [mm?] INFO: rcu detected stall in security_file_ioctl (9)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    864e3396976e net: gso: Forbid IPv6 TSO with extensions on ..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=144e26f0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c321f33e4545e2a1
dashboard link: https://syzkaller.appspot.com/bug?extid=b6f8640465bdf47ca708
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=170a43bc580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/576f260f8fdb/disk-864e3396.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/90ce2b40a623/vmlinux-864e3396.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e9f2532beed2/bzImage-864e3396.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6f8640465bdf47ca708@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (3 ticks this GP) idle=3c4c/1/0x4000000000000000 softirq=18260/18260 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=12221, q=404 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6109 Comm: syz.0.22 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:137 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x29f/0x2c0 mm/kasan/generic.c:189
Code: f3 49 83 c3 05 eb 07 4d 01 f3 49 83 c3 06 4d 89 dc 4d 85 db 0f 84 44 ff ff ff 4d 01 d1 4d 39 cc 75 11 41 83 e0 07 45 0f be 09 <45> 39 c8 0f 8c 2b ff ff ff 0f b6 d2 e8 a0 ef ff ff 34 01 e9 1c ff
RSP: 0018:ffffc90000a08ae8 EFLAGS: 00000006
RAX: 00000000ffffff01 RBX: ffffffffffffffff RCX: ffffffff819e00e1
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000a08b60
RBP: ffffc90000a08bd0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200014116c R12: fffff5200014116c
R13: ffffffff99d527c0 R14: fffff5200014116d R15: 1ffff9200014116c
FS:  00007f17a98396c0(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 000000006fc8c000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1301 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
 do_raw_spin_lock+0x121/0x290 kernel/locking/spinlock_debug.c:116
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162
 debug_object_activate+0xbb/0x420 lib/debugobjects.c:818
 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline]
 debug_activate kernel/time/hrtimer.c:484 [inline]
 enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088
 __run_hrtimer kernel/time/hrtimer.c:1778 [inline]
 __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:86 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:104 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:129 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x89/0x2c0 mm/kasan/generic.c:189
Code: ff df 4f 8d 1c 17 49 ff c8 4d 89 c1 49 c1 e9 03 48 bb 01 00 00 00 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 <4d> 85 e4 0f 84 41 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00
RSP: 0018:ffffc90003037910 EFLAGS: 00000283
RAX: ffffffff8b758901 RBX: dffffc0000000001 RCX: ffffffff8b7589f6
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8c935a00
RBP: ffffffff8c935a08 R08: ffffffff8c935a07 R09: 1ffffffff1926b40
R10: dffffc0000000000 R11: fffffbfff1926b40 R12: 0000000000000001
R13: ffffc90003037aa0 R14: fffffbfff1926b41 R15: 1ffffffff1926b40
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 vsnprintf+0x386/0xf00 lib/vsprintf.c:2878
 dynamic_dname+0xfc/0x1b0 fs/d_path.c:308
 tomoyo_realpath_from_path+0x170/0x5d0 security/tomoyo/realpath.c:258
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x1e8/0x5a0 security/tomoyo/file.c:723
 security_file_ioctl+0xcb/0x2d0 security/security.c:2943
 __do_sys_ioctl fs/ioctl.c:592 [inline]
 __se_sys_ioctl+0x47/0x170 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f17a898ebe9
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:00007f17a9839038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f17a8bb5fa0 RCX: 00007f17a898ebe9
RDX: 0000200000000600 RSI: 0000000000008933 RDI: 0000000000000003
RBP: 00007f17a8a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f17a8bb6038 R14: 00007f17a8bb5fa0 R15: 00007ffccbbdc5c8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g12221 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3961
rcu: rcu_preempt kthread starved for 10502 jiffies! g12221 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.