INFO: rcu detected stall in vm_area_alloc

Status: upstream: reported on 2026/06/08 20:55
Reported-by: syzbot+aa8cbd84a995ad73d540@syzkaller.appspotmail.com
First crash: 102d, last: 20d
▶ ▼ 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 898d 898d 0/29 auto-obsoleted due to no activity on 2024/07/03 04:13
linux-6.1 INFO: rcu detected stall in vm_area_alloc 1 1 539d 539d 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 2445d 2445d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in vm_area_alloc (3) mm 1 2 995d 996d 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 2480d 2482d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in vm_area_alloc (6) prio:normal mm 1 syz error error 20 10d 477d 0/29 upstream: reported syz repro on 2025/05/30 07:37
upstream INFO: rcu detected stall in vm_area_alloc (5) bpf mm 1 18 622d 743d 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 435d 435d 0/1 auto-obsoleted due to no activity on 2025/10/08 16:56

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6989/1:b..l P6122/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=22745, q=616 ncpus=1)
task:kworker/u4:8    state:R  running task     stack:24360 pid:6122  ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:678
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0000:ffffc900050d79c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: c1491ff230727b00
RDX: 0000000000000000 RSI: ffffffff8acadd60 RDI: ffffffff8b1d3360
RBP: ffffc900050d7ae0 R08: dffffc0000000000 R09: 1ffffffff223dea0
R10: dffffc0000000000 R11: fffffbfff223dea1 R12: 1ffff92000a1af44
R13: ffffffff8d131da0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 batadv_nc_process_nc_paths+0xdb/0x380 net/batman-adv/network-coding.c:687
 batadv_nc_worker+0x423/0x600 net/batman-adv/network-coding.c:728
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
task:sed             state:R  running task     stack:24360 pid:6989  ppid:6988   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc9000370f860 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0b456d61070dbb00
RDX: 0000000000000000 RSI: ffffffff8acadd60 RDI: ffffffff8b1d3360
RBP: ffffc9000370f978 R08: dffffc0000000000 R09: 1ffffffff223dea0
R10: dffffc0000000000 R11: fffffbfff223dea1 R12: 1ffff920006e1f18
R13: ffffffff8d131da0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 get_obj_cgroup_from_current+0xf0/0x280 mm/memcontrol.c:3058
 memcg_slab_pre_alloc_hook mm/slab.h:492 [inline]
 slab_pre_alloc_hook+0x8c/0x300 mm/slab.h:719
 slab_alloc_node mm/slub.c:3477 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x5a/0x2c0 mm/slub.c:3519
 vma_lock_alloc kernel/fork.c:461 [inline]
 vm_area_alloc+0x10e/0x1d0 kernel/fork.c:492
 __mmap_region mm/mmap.c:2770 [inline]
 mmap_region+0xcfa/0x2090 mm/mmap.c:2941
 do_mmap+0x98f/0x10a0 mm/mmap.c:1385
 vm_mmap_pgoff+0x1c4/0x3f0 mm/util.c:556
 ksys_mmap_pgoff+0x4c9/0x720 mm/mmap.c:1431
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f36f26ef242
RSP: 002b:00007ffc81af9f08 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f36f23c2000 RCX: 00007f36f26ef242
RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007f36f23c2000
RBP: 0000000000000812 R08: 0000000000000003 R09: 000000000005f000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffc81af9fc8
R13: 00007f36f23ce6b0 R14: 00007ffc81afa340 R15: 00000fff9035f3e4
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g22745 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:26664 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 6990 Comm: vhost-6986 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90003087720 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8454f25b3eb5cc00
RDX: 0000000000000000 RSI: ffffffff8acadd60 RDI: ffffffff8b1d3360
RBP: ffffc90003087828 R08: dffffc0000000000 R09: 1ffffffff223dea6
R10: dffffc0000000000 R11: fffffbfff223dea7 R12: 1ffff92000610ef0
R13: ffff88801c38e0a0 R14: 0000000000000246 R15: dffffc0000000000
FS:  00007f91cf67a6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f36f23caa10 CR3: 000000005ef85000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 internal_get_user_pages_fast+0x1fc/0x27a0 mm/gup.c:3209
 set_bit_to_user drivers/vhost/vhost.c:2202 [inline]
 log_write+0xc3/0x370 drivers/vhost/vhost.c:2228
 vhost_update_used_flags+0x1c3/0x290 drivers/vhost/vhost.c:2347
 vhost_enable_notify+0xb7/0x7e0 drivers/vhost/vhost.c:2907
 vhost_vsock_handle_tx_kick+0x2d0/0xde0 drivers/vhost/vsock.c:505
 vhost_run_work_list+0x13d/0x1b0 drivers/vhost/vhost.c:419
 vhost_task_fn+0x29a/0x3f0 kernel/vhost_task.c:49
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/29 15:48 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in vm_area_alloc
2026/06/08 20:55 linux-6.6.y 924b4a879cbb 656e94c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in vm_area_alloc
* Struck through repros no longer work on HEAD.