INFO: rcu detected stall in vm_area_alloc (6)

Status: upstream: reported syz repro on 2025/05/30 07:37
Subsystems: mm
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+2ddfdc64a6b68a324ae2@syzkaller.appspotmail.com
First crash: 445d, last: 17d
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
8aa16138 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: rcu detected stall in vm_area_alloc (6) 2026/05/24 05:12 2026/05/24 05:12 2026/05/24 06:02 c69befb3
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly bpf report (Nov 2025) 0 (1) 2025/11/05 08:25
[syzbot] [kernel?] INFO: rcu detected stall in vm_area_alloc (6) 0 (1) 2025/05/30 07:37
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in vm_area_alloc (4) bpf 1 1 862d 862d 0/29 auto-obsoleted due to no activity on 2024/07/03 04:13
linux-6.6 INFO: rcu detected stall in vm_area_alloc 1 1 66d 66d 0/2 upstream: reported on 2026/06/08 20:55
linux-6.1 INFO: rcu detected stall in vm_area_alloc 1 1 503d 503d 0/3 auto-obsoleted due to no activity on 2025/07/06 19:56
upstream INFO: rcu detected stall in vm_area_alloc (2) mm 1 1 2410d 2410d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in vm_area_alloc (3) mm 1 2 959d 961d 0/29 auto-obsoleted due to no activity on 2024/03/27 19:02
upstream INFO: rcu detected stall in vm_area_alloc mm 1 3 2445d 2446d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in vm_area_alloc (5) bpf mm 1 18 586d 707d 0/29 auto-obsoleted due to no activity on 2025/04/05 06:19
android-6-12 INFO: rcu detected stall in vm_area_alloc 1 1 399d 399d 0/1 auto-obsoleted due to no activity on 2025/10/08 16:56
▶ ▼ Last patch testing requests (6)
Created Duration User Patch Repo Result
2026/08/14 00:56 24m retest repro net-next report job log log
2026/07/02 08:08 1h26m retest repro upstream log
2026/04/23 02:02 29m retest repro upstream report log
2025/11/27 23:57 45m retest repro upstream report log
2025/08/23 12:16 53m retest repro upstream report log
2025/06/10 20:13 22m retest repro upstream report log
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2026/02/03 16:55 19m bisect fix upstream error job log
2025/12/15 11:22 2h25m bisect fix upstream OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=51a4/1/0x4000000000000000 softirq=18198/18202 fqs=0
rcu: 	(detected by 1, t=10502 jiffies, g=9149, q=175 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6052 Comm: modprobe Not tainted 6.15.0-rc7-syzkaller-00175-g0f8c0258bf04 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:577 [inline]
RIP: 0010:queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
RIP: 0010:do_raw_spin_unlock+0x152/0x230 kernel/locking/spinlock_debug.c:142
Code: 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 95 00 00 00 48 c7 c0 50 20 22 8e c7 43 08 ff ff ff ff 48 ba 00 00 00 00 00 fc ff df <48> c1 e8 03 80 3c 10 00 0f 85 ba 00 00 00 48 83 3d 78 ab 89 0c 00
RSP: 0018:ffffc90000007d18 EFLAGS: 00000046
RAX: ffffffff8e222050 RBX: ffffffff9adbe550 RCX: ffffffff819873c3
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffffff9adbe550
RBP: ffffffff9adbe558 R08: 0000000000000000 R09: fffffbfff35b7caa
R10: ffffffff9adbe553 R11: 0000000000000000 R12: ffffffff9adbe560
R13: dffffc0000000000 R14: ffff88802ae6b340 R15: 1ffff92000000fac
FS:  0000000000000000(0000) GS:ffff8881249da000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe27243ff8 CR3: 000000005cd34000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_unlock_irqrestore+0x22/0x80 kernel/locking/spinlock.c:194
 debug_object_deactivate+0x1ec/0x3a0 lib/debugobjects.c:888
 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline]
 debug_deactivate kernel/time/hrtimer.c:490 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1729 [inline]
 __hrtimer_run_queues+0x46f/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:1038 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x3f0 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+0x62/0x350 kernel/locking/lockdep.c:5870
Code: 39 0c 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 52 0a ed 0e 0f 82 74 02 00 00 8b 35 ea 39 ed 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 29 39 0c 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc90003fdf3c0 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3bfc00 RCX: 00000000ad97940f
RDX: 0000000000000000 RSI: ffffffff8dbbf273 RDI: ffffffff8bf4a520
RBP: 0000000000000002 R08: 461794d577a429a7 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 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]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 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
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4203
 vm_area_alloc+0x1f/0x160 kernel/fork.c:441
 __mmap_new_vma mm/vma.c:2403 [inline]
 __mmap_region+0xfd0/0x27c0 mm/vma.c:2520
 mmap_region+0x1ab/0x3f0 mm/vma.c:2598
 do_mmap+0xd8e/0x11b0 mm/mmap.c:561
 vm_mmap_pgoff+0x281/0x450 mm/util.c:579
 ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:607
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa439aa5242
Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00
RSP: 002b:00007ffe27243898 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa439aa5242
RDX: 0000000000000001 RSI: 00000000000c1918 RDI: 0000000000000000
RBP: 0000000000000802 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000802 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa439a790c0 R14: 00007ffe27243ca0 R15: 00000fffc4e48716
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g9149 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:28664 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 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: 65 Comm: kworker/u8:4 Not tainted 6.15.0-rc7-syzkaller-00175-g0f8c0258bf04 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x4a5/0x1290 kernel/smp.c:885
Code: 89 ee e8 de 12 0c 00 85 ed 74 48 48 8b 44 24 20 49 89 c4 83 e0 07 49 c1 ec 03 48 89 c5 4d 01 f4 83 c5 03 e8 7d 17 0c 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 de 0b 00 00 8b 43 08 31
RSP: 0018:ffffc90001567938 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8441720 RCX: ffffffff81af2e99
RDX: ffff88801db90000 RSI: ffffffff81af2e73 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170882e5
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b853b040
FS:  0000000000000000(0000) GS:ffff888124ada000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5422dddd58 CR3: 000000000e180000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2757 [inline]
 text_poke_bp_batch+0x566/0x760 arch/x86/kernel/alternative.c:3050
 text_poke_flush arch/x86/kernel/alternative.c:3158 [inline]
 text_poke_flush arch/x86/kernel/alternative.c:3155 [inline]
 text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:3165
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x376/0x550 kernel/jump_label.c:919
 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:850 [inline]
 toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/26 07:32 upstream 0f8c0258bf04 2d4582d0 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in vm_area_alloc
2026/07/28 13:18 net-next edc84a9396ac 45ae1df4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: rcu detected stall in vm_area_alloc
2026/05/24 03:46 upstream 4cbfe4502e3d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in vm_area_alloc
2026/05/21 03:47 upstream df685633c3db 41b8c833 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in vm_area_alloc
2026/04/23 13:16 upstream 2a4c0c11c019 b10da5ec .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in vm_area_alloc
2026/04/09 00:20 upstream 7f87a5ea75f0 d9b7f621 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in vm_area_alloc
2026/02/09 05:53 upstream e98f34af6116 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in vm_area_alloc
2026/01/04 11:21 upstream aacb0a6d604a d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in vm_area_alloc
2025/11/13 21:35 upstream 2ccec5944606 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in vm_area_alloc
2025/10/31 04:58 upstream e53642b87a4f 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in vm_area_alloc
2025/08/09 11:35 upstream 038d61fd6422 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in vm_area_alloc
2025/06/23 04:36 upstream b67ec639010f d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in vm_area_alloc
2025/05/27 17:53 upstream 914873bc7df9 874a1386 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in vm_area_alloc
2025/11/08 07:52 net 4da4e4bde1c4 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in vm_area_alloc
* Struck through repros no longer work on HEAD.