INFO: rcu detected stall in keyctl

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-5.15	INFO: rcu detected stall in keyctl	1				1	5d08h	5d08h	0/3	upstream: reported on 2025/12/05 22:03
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=34dc/1/0x4000000000000000 softirq=138052/138052 fqs=1
rcu: 	(detected by 1, t=10502 jiffies, g=104809, q=67 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 23669 Comm: syz.0.4319 Not tainted 6.16.0-syzkaller-08685-g260f6f4fda93 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline]
RIP: 0010:lock_release+0x45/0x2f0 kernel/locking/lockdep.c:5879
Code: e9 b8 38 12 48 89 44 24 10 31 c0 0f 1f 44 00 00 65 8b 05 02 b9 38 12 83 f8 07 0f 87 38 02 00 00 89 c0 48 0f a3 05 4b 0d 10 0f <0f> 82 b1 01 00 00 8b 3d 33 3f 10 0f 85 ff 0f 84 25 01 00 00 65 8b
RSP: 0018:ffffc90000007de0 EFLAGS: 00000097
RAX: 0000000000000000 RBX: ffff8880b8427c98 RCX: ffffffff81a82881
RDX: 1ffff1100594da6d RSI: ffffffff81a82f09 RDI: ffff8880b8427c98
RBP: 0000000000000046 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff81a82f09
R13: 1865368624000000 R14: ffff88802ca6d340 R15: ffffffff89a09ea0
FS:  00007f57ca4636c0(0000) GS:ffff888124719000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f417ff8 CR3: 00000000955d8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000040020
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x1a/0x80 kernel/locking/spinlock.c:194
 __run_hrtimer kernel/time/hrtimer.c:1757 [inline]
 __hrtimer_run_queues+0x529/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x9f/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:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872
Code: b2 38 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 92 06 10 0f 0f 82 74 02 00 00 8b 35 7a 38 10 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 e9 b1 38 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc9000471f6c8 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e5c1060 RCX: 00000000ef9d33e4
RDX: 0000000000000000 RSI: ffffffff8ddf01fe RDI: ffffffff8c15fc80
RBP: 0000000000000002 R08: 0ac0d5affe09d4ff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 is_bpf_text_address+0x36/0x1a0 kernel/bpf/core.c:776
 kernel_text_address kernel/extable.c:125 [inline]
 kernel_text_address+0x8d/0x100 kernel/extable.c:94
 __kernel_text_address+0xd/0x40 kernel/extable.c:79
 unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0xa6/0x100 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x8e/0xc0 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:576
 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:233 [inline]
 slab_free_hook mm/slub.c:2416 [inline]
 slab_free mm/slub.c:4679 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4878
 mpi_free_limb_space lib/crypto/mpi/mpiutil.c:74 [inline]
 mpi_free+0x9a/0x160 lib/crypto/mpi/mpiutil.c:119
 dh_clear_ctx+0x70/0xa0 crypto/dh.c:26
 crypto_exit_ops crypto/api.c:375 [inline]
 crypto_destroy_tfm crypto/api.c:683 [inline]
 crypto_destroy_tfm+0x135/0x2b0 crypto/api.c:670
 crypto_free_kpp include/crypto/kpp.h:169 [inline]
 __keyctl_dh_compute+0xb28/0x10e0 security/keys/dh.c:290
 keyctl_dh_compute+0xd2/0x140 security/keys/dh.c:312
 __do_sys_keyctl+0x4df/0x590 security/keys/keyctl.c:1978
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f57c958eb69
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:00007f57ca463038 EFLAGS: 00000246 ORIG_RAX: 00000000000000fa
RAX: ffffffffffffffda RBX: 00007f57c97b5fa0 RCX: 00007f57c958eb69
RDX: 0000200000000480 RSI: 0000200000000400 RDI: 0000000000000017
RBP: 00007f57c9611df1 R08: 0000200000000580 R09: 0000000000000000
R10: 00000000000000c7 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f57c97b5fa0 R15: 00007fff97b6ddf8
 </TASK>
rcu: rcu_preempt kthread starved for 10495 jiffies! g104809 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:27784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5df0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 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: 23634 Comm: syz.7.4310 Not tainted 6.16.0-syzkaller-08685-g260f6f4fda93 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xe02/0x1600 kernel/smp.c:877
Code: 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 b5 11 0c 00 f3 90 41 0f b6 45 00 <40> 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31 ff 83 e0 01 41
RSP: 0018:ffffc9000467f708 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8442260 RCX: ffffffff81af71b1
RDX: ffff88807b140000 RSI: ffffffff81af718b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffed101708844d R14: 0000000000000001 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124819000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6911c20d58 CR3: 000000007b4e5000 CR4: 00000000003526f0
DR0: 0000000000000007 DR1: 7fffffffffffffff DR2: 0000000000000fb3
DR3: 0000000000000101 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1044
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x4a0/0x1790 arch/x86/mm/tlb.c:1451
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline]
 tlb_flush_mmu mm/mmu_gather.c:403 [inline]
 tlb_finish_mmu+0x3c9/0x7c0 mm/mmu_gather.c:497
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1125
 mmput+0x62/0x70 kernel/fork.c:1148
 exit_mm kernel/exit.c:581 [inline]
 do_exit+0x7c7/0x2bf0 kernel/exit.c:952
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1105
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:224 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94e5f8eb69
Code: Unable to access opcode bytes at 0x7f94e5f8eb3f.
RSP: 002b:00007f94e6eb4038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: 0000000000010106 RBX: 00007f94e61b6080 RCX: 00007f94e5f8eb69
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007f94e6011df1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f94e61b6080 R15: 00007ffec30cb288
 </TASK>