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INFO: rcu detected stall in kvm_vm_release

Status: upstream: reported on 2026/02/18 08:30
Reported-by: syzbot+3680421d1bb466b52e37@syzkaller.appspotmail.com
First crash: 20h25m, last: 20h25m
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in kvm_vm_release (2) fs 1 1 868d 868d 0/29 auto-obsoleted due to no activity on 2024/01/02 09:35
upstream INFO: rcu detected stall in kvm_vm_release kernel 1 1 2103d 2103d 0/29 auto-closed as invalid on 2020/08/15 10:19
upstream INFO: rcu detected stall in kvm_vm_release (3) bpf net 1 1 627d 627d 0/29 auto-obsoleted due to no activity on 2024/08/30 21:11
android-6-12 BUG: soft lockup in kvm_vm_release 1 2 135d 138d 0/1 auto-obsoleted due to no activity on 2026/01/04 18:02

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8309/1:b..l
	(detected by 1, t=10502 jiffies, g=39493, q=369 ncpus=2)
task:syz.3.971       state:R  running task     stack:26224 pid:8309  ppid:4280   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:244 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x80 kernel/kcov.c:313
Code: 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 03 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 48 8b 04 24 <65> 48 8b 15 24 f8 7f 7e 65 8b 0d 25 f8 7f 7e 81 e1 00 01 ff 00 74
RSP: 0018:ffffc900033577e8 EFLAGS: 00000246
RAX: ffffffff818f1487 RBX: 0000000000000000 RCX: ffff88801bfe1dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff215ea48
R10: dffffc0000000000 R11: fffffbfff215ea49 R12: 0000000000000132
R13: dffffc0000000000 R14: 00007fc7dbd9c629 R15: 0000000000000000
 rcu_read_unlock include/linux/rcupdate.h:820 [inline]
 is_bpf_text_address+0x1f7/0x2a0 kernel/bpf/core.c:737
 kernel_text_address+0x9c/0xd0 kernel/extable.c:125
 __kernel_text_address+0x9/0x30 kernel/extable.c:79
 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
 kvm_destroy_vm_debugfs virt/kvm/kvm_main.c:1039 [inline]
 kvm_destroy_vm virt/kvm/kvm_main.c:1305 [inline]
 kvm_put_kvm+0x1de/0x1950 virt/kvm/kvm_main.c:1370
 kvm_vm_release+0x42/0x50 virt/kvm/kvm_main.c:1393
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc7dbd9c629
RSP: 002b:00007ffcae14f658 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fc7dc017da0 RCX: 00007fc7dbd9c629
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fc7dc017da0 R08: 00007fc7dc016038 R09: 0000000000000000
R10: 00000000005f902c R11: 0000000000000246 R12: 000000000004fa36
R13: 00007fc7dc01609c R14: 000000000004f77f R15: 00007fc7dc016090
 </TASK>
rcu: rcu_preempt kthread starved for 10491 jiffies! g39493 f0x0 RCU_GP_DOING_FQS(6) ->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:28080 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:rcu_gp_fqs kernel/rcu/tree.c:-1 [inline]
RIP: 0010:rcu_gp_fqs_loop+0x579/0x1340 kernel/rcu/tree.c:1728
Code: 01 00 00 00 48 0f 48 d8 b9 01 00 00 00 45 31 f6 0f b6 05 ee 77 45 0b 84 c0 0f 85 bb fb ff ff e9 b0 fb ff ff 8b 1d 1f 78 45 0b <48> 8b 44 24 18 80 3c 30 00 74 16 48 c7 c7 00 f2 80 8c e8 30 a3 65
RSP: 0018:ffffc90000157cc0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: dffffc0000000000 RDI: 00000000ffffffff
RBP: ffffc90000157e10 R08: ffffffff8cb330db R09: 1ffffffff196661b
R10: dffffc0000000000 R11: fffffbfff196661c R12: 0000000000000000
R13: ffffffff8cb33080 R14: ffffc90000157d88 R15: 0000000000000000
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </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:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/18 08:30 linux-6.1.y 8ce36b2849ef 39751c21 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in kvm_vm_release
* Struck through repros no longer work on HEAD.