INFO: rcu detected stall in sys_mlock (3)

Status: auto-obsoleted due to no activity on 2026/05/20 22:34
Subsystems: mm
[Documentation on labels]
First crash: 422d, last: 179d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_mlock mm 1 1 796d 796d 0/29 auto-obsoleted due to no activity on 2024/09/11 05:27
linux-6.6 INFO: rcu detected stall in sys_mlock 1 1 336d 336d 0/2 auto-obsoleted due to no activity on 2025/12/25 08:53
linux-5.15 INFO: rcu detected stall in sys_mlock 1 1 422d 422d 0/3 auto-obsoleted due to no activity on 2025/09/29 15:14
upstream INFO: rcu detected stall in sys_mlock (2) mm kasan 1 2 648d 661d 0/29 auto-obsoleted due to no activity on 2025/02/05 20:37
linux-6.1 INFO: rcu detected stall in sys_mlock 1 1 825d 825d 0/3 auto-obsoleted due to no activity on 2024/08/23 11:10
linux-5.15 INFO: rcu detected stall in sys_mlock (2) origin:lts-only 1 syz, C 2 2d05h 37d 0/3 upstream: reported C repro on 2026/07/12 06:18

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P29154/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=158593, q=451578 ncpus=2)
task:syz.1.5264      state:R  running task     stack:26200 pid:29154 tgid:29152 ppid:17928  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0xfee/0x60e0 kernel/sched/core.c:6907
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7234
 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0xbb3/0x1ea0 arch/x86/kernel/unwind_orc.c:656
Code: 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 75 0e 00 00 4c 89 c0 49 c7 45 58 00 00 00 00 <48> ba 00 00 00 00 00 fc ff df 48 c1 e8 03 0f b6 34 10 49 8d 40 01
RSP: 0018:ffffc90010556fc0 EFLAGS: 00000246
RAX: ffffffff91850958 RBX: 0000000000000001 RCX: ffffffff91850954
RDX: 1ffff920020aae11 RSI: 1ffff920020aae0f RDI: ffffc90010557088
RBP: ffffc90010557078 R08: ffffffff91850958 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000015a8f R12: ffffc90010557080
R13: ffffc90010557030 R14: ffffc90010557918 R15: ffffc90010557064
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x162/0x1e0 mm/page_owner.c:165
 __set_page_owner+0x8c/0x540 mm/page_owner.c:341
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2485
 folio_alloc_mpol_noprof+0x36/0x340 mm/mempolicy.c:2504
 vma_alloc_folio_noprof+0xed/0x1d0 mm/mempolicy.c:2539
 folio_prealloc mm/memory.c:1204 [inline]
 alloc_anon_folio mm/memory.c:5208 [inline]
 do_anonymous_page+0xb3a/0x1fb0 mm/memory.c:5265
 do_pte_missing mm/memory.c:4475 [inline]
 handle_pte_fault mm/memory.c:6316 [inline]
 __handle_mm_fault+0x1d42/0x2b60 mm/memory.c:6454
 handle_mm_fault+0x36d/0xa20 mm/memory.c:6623
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0xf9c/0x34d0 mm/gup.c:1428
 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860
 __mm_populate+0x107/0x3a0 mm/gup.c:1963
 do_mlock+0x3f0/0x7f0 mm/mlock.c:653
 __do_sys_mlock mm/mlock.c:661 [inline]
 __se_sys_mlock mm/mlock.c:659 [inline]
 __x64_sys_mlock+0x59/0x80 mm/mlock.c:659
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff37379c629
RSP: 002b:00007ff3745e4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000095
RAX: ffffffffffffffda RBX: 00007ff373a15fa0 RCX: 00007ff37379c629
RDX: 0000000000000000 RSI: 0000000000800000 RDI: 0000200000000000
RBP: 00007ff373832b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff373a16038 R14: 00007ff373a15fa0 R15: 00007ffd21560cf8
 </TASK>
rcu: rcu_preempt kthread starved for 1834 jiffies! g158593 f0x2 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:28584 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0xfee/0x60e0 kernel/sched/core.c:6907
 __schedule_loop kernel/sched/core.c:6989 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7004
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2 Comm: kthreadd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__lock_acquire+0x1bb/0x2630 kernel/locking/lockdep.c:5174
Code: 00 04 00 41 c1 e1 13 44 09 f0 09 d0 8b 94 24 c8 00 00 00 44 09 c8 c1 e2 14 09 d0 8b 94 24 b8 00 00 00 c1 e2 15 09 d0 8b 53 20 <81> e2 ff 1f 00 00 09 d0 89 43 20 8b 84 24 c0 00 00 00 89 43 24 4c
RSP: 0018:ffffc90000006798 EFLAGS: 00000006
RAX: 0000000000022000 RBX: ffff88801e2a5530 RCX: 0000000000000007
RDX: 00000000000c2007 RSI: 0000000000000001 RDI: ffffffff8e7e93e0
RBP: ffff88801e2a4900 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8e7e93e0 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000007 R14: 0000000000020000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124348000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555720b24e8 CR3: 0000000033ab4000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
 rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0xd1/0x1ea0 arch/x86/kernel/unwind_orc.c:495
 __unwind_start+0x3d1/0x7f0 arch/x86/kernel/unwind_orc.c:773
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kmem_cache_free+0x124/0x6a0 mm/slub.c:6254
 kfree_skbmem+0x19a/0x210 net/core/skbuff.c:1151
 __kfree_skb net/core/skbuff.c:1218 [inline]
 sk_skb_reason_drop+0x10f/0x1b0 net/core/skbuff.c:1255
 tpacket_rcv+0x1e8/0x3810 net/packet/af_packet.c:2497
 dev_queue_xmit_nit+0x6fc/0xa60 net/core/dev.c:2599
 xmit_one net/core/dev.c:3860 [inline]
 dev_hard_start_xmit+0x2f5/0x7d0 net/core/dev.c:3880
 __dev_queue_xmit+0x6dd/0x4750 net/core/dev.c:4829
 dev_queue_xmit include/linux/netdevice.h:3384 [inline]
 neigh_hh_output include/net/neighbour.h:540 [inline]
 neigh_output include/net/neighbour.h:554 [inline]
 ip_finish_output2+0xf4a/0x24d0 net/ipv4/ip_output.c:237
 __ip_finish_output.part.0+0x444/0x6f0 net/ipv4/ip_output.c:315
 __ip_finish_output net/ipv4/ip_output.c:303 [inline]
 ip_finish_output net/ipv4/ip_output.c:325 [inline]
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip_output+0x39b/0xec0 net/ipv4/ip_output.c:438
 dst_output include/net/dst.h:470 [inline]
 ip_local_out+0x35b/0x4a0 net/ipv4/ip_output.c:131
 synproxy_send_tcp.isra.0+0x481/0x680 net/netfilter/nf_synproxy_core.c:440
 synproxy_send_client_synack+0x6ea/0x970 net/netfilter/nf_synproxy_core.c:485
 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:60 [inline]
 nft_synproxy_do_eval+0xa73/0xd50 net/netfilter/nft_synproxy.c:142
 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
 nft_do_chain+0x2e8/0x1930 net/netfilter/nf_tables_core.c:285
 nft_do_chain_inet+0xee/0x340 net/netfilter/nft_chain_filter.c:161
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xbf/0x220 net/netfilter/core.c:623
 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273
 NF_HOOK include/linux/netfilter.h:316 [inline]
 ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262
 dst_input include/net/dst.h:480 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:453 [inline]
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 ip_rcv+0x2d9/0x5d0 net/ipv4/ip_input.c:573
 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6149
 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6262
 process_backlog+0x37a/0x1580 net/core/dev.c:6614
 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7678
 napi_poll net/core/dev.c:7741 [inline]
 net_rx_action+0xa40/0xf20 net/core/dev.c:7893
 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xef/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x1b9/0x320 kernel/locking/lockdep.c:5893
Code: 00 00 41 f7 c6 00 02 00 00 0f 85 de 00 00 00 48 8b 44 24 10 65 48 2b 05 5d b0 28 12 0f 85 63 01 00 00 48 83 c4 18 5b 5d 41 5c <41> 5e 41 5f c3 cc cc cc cc 65 8b 05 6b b0 28 12 83 f8 07 0f 87 de
RSP: 0018:ffffc90000077580 EFLAGS: 00000282
RAX: 0000000000000000 RBX: ffffc90000077cd8 RCX: ffffc9000007755c
RDX: 0000000000000001 RSI: ffffffff8de4badd RDI: ffffffff8c1aefa0
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000000c6df R12: ffffc90000077658
R13: ffffc90000077608 R14: 0000000000000202 R15: 0000000000000002
 rcu_lock_release include/linux/rcupdate.h:322 [inline]
 rcu_read_unlock include/linux/rcupdate.h:881 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0x3c3/0x1ea0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x162/0x1e0 mm/page_owner.c:165
 __reset_page_owner+0x84/0x190 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 __do_kmalloc_node mm/slub.c:5218 [inline]
 __kmalloc_noprof+0x2b9/0x850 mm/slub.c:5231
 kmalloc_noprof include/linux/slab.h:966 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 lsm_blob_alloc+0x68/0x90 security/security.c:192
 lsm_task_alloc security/security.c:244 [inline]
 security_task_alloc+0x2a/0x260 security/security.c:2682
 copy_process+0x2531/0x7a10 kernel/fork.c:2205
 kernel_clone+0xfc/0x9a0 kernel/fork.c:2654
 kernel_thread+0xdb/0x120 kernel/fork.c:2715
 create_kthread kernel/kthread.c:490 [inline]
 kthreadd+0x498/0x7a0 kernel/kthread.c:849
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/19 22:32 upstream 2b7a25df823d 73a252ac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_mlock
2025/12/08 06:54 upstream 67a454e6b1c6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_mlock
2025/11/07 17:40 upstream 4a0c9b339199 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_mlock
2025/10/29 06:55 upstream 8eefed8f65cc fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_mlock
2025/10/03 15:45 upstream e406d57be7bd 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_mlock
2025/06/22 06:54 upstream 739a6c93cc75 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in sys_mlock
2025/09/23 10:29 linux-next 846bd2225ec3 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_mlock
2025/08/23 17:46 linux-next 7fa4d8dc380f bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in sys_mlock
* Struck through repros no longer work on HEAD.