INFO: rcu detected stall in odev_release (2)

Status: auto-obsoleted due to no activity on 2026/08/05 02:26
Subsystems: mm
Labels: prio:high
[Documentation on labels]
First crash: 192d, last: 132d
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ID Workflow Result Correct Bug Created Started Finished Revision
801e2fa7 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ✅ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: rcu detected stall in odev_release (2) 2026/05/15 21:00 2026/05/15 21:00 2026/05/15 21:05 efdaf0f9
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in odev_release sound modules mm 1 3 384d 488d 0/29 auto-obsoleted due to no activity on 2025/11/26 17:50

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P18750/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=135249, q=764 ncpus=2)
task:syz.0.4001      state:R  running task     stack:24408 pid:18750 tgid:18750 ppid:15021  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7189
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
 irqentry_exit+0x14f/0x730 kernel/entry/common.c:164
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:60 [inline]
RIP: 0010:unwind_next_frame+0x1a7a/0x2550 arch/x86/kernel/unwind_orc.c:694
Code: 00 74 08 4c 89 ff e8 d5 ee b9 00 49 8b 07 4d 39 e5 0f 96 c1 4c 39 e0 0f 97 c2 20 ca 80 fa 01 0f 85 63 01 00 00 49 8d 4c 24 08 <4c> 39 e9 0f 86 55 01 00 00 48 39 c1 0f 87 4c 01 00 00 4c 3b a4 24
RSP: 0018:ffffc90005947258 EFLAGS: 00000246
RAX: ffffc90005948000 RBX: ffffffff90c66601 RCX: ffffc90005947ea8
RDX: ffffc90005947301 RSI: dffffc0000000000 RDI: ffffc90005947330
RBP: dffffc0000000000 R08: ffffc90005947e90 R09: 0000000000000000
R10: ffffc90005947378 R11: fffff52000b28e71 R12: ffffc90005947ea0
R13: ffffc90005940000 R14: ffffc90005947328 R15: ffffc90005947338
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
 __slab_free+0x274/0x2c0 mm/slub.c:5612
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 __kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5414
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 snd_seq_port_connect+0x6a/0x450 sound/core/seq/seq_ports.c:575
 snd_seq_ioctl_subscribe_port+0x378/0x7c0 sound/core/seq/seq_clientmgr.c:1473
 snd_seq_oss_midi_open+0x4a2/0x8a0 sound/core/seq/oss/seq_oss_midi.c:341
 snd_seq_oss_synth_reset+0x3ca/0x8b0 sound/core/seq/oss/seq_oss_synth.c:380
 snd_seq_oss_reset+0x5a/0x240 sound/core/seq/oss/seq_oss_init.c:430
 snd_seq_oss_release+0xfe/0x330 sound/core/seq/oss/seq_oss_init.c:407
 odev_release+0x53/0x70 sound/core/seq/oss/seq_oss.c:141
 __fput+0x44f/0xa60 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbb73b9cdd9
RSP: 002b:00007fbb73f3fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fbb73e17da0 RCX: 00007fbb73b9cdd9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fbb73e17da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007fbb73e17cb0 R11: 0000000000000246 R12: 00000000000ce805
R13: 00007fbb73e1627c R14: 00000000000ce6c3 R15: 00007fbb73e16270
 </TASK>
rcu: rcu_preempt kthread starved for 839 jiffies! g135249 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:I stack:27544 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: wg-kex-wg0 wg_packet_handshake_receive_worker
RIP: 0010:__lock_release kernel/locking/lockdep.c:5565 [inline]
RIP: 0010:lock_release+0x16e/0x3c0 kernel/locking/lockdep.c:5889
Code: 81 e1 00 00 e0 ff 25 ff ff 1f 00 01 c8 05 00 00 e0 ff 81 c1 00 00 e0 ff 89 45 20 85 c9 0f 85 e6 00 00 00 45 89 af 88 0b 00 00 <48> 8b 45 00 49 89 87 80 0b 00 00 41 39 d5 0f 84 cb 00 00 00 41 ff
RSP: 0018:ffffc90000a07db0 EFLAGS: 00000083
RAX: 0000000000022007 RBX: 0000000000000202 RCX: 0000000080000101
RDX: 0000000000000005 RSI: ffffffff8e95cd60 RDI: ffff88801defe898
RBP: ffff88801defe898 R08: ffffc90000a08a90 R09: 0000000000000000
R10: ffffc90000a07f38 R11: fffff52000140fe9 R12: 0000000000000005
R13: 0000000000000005 R14: ffffffff8e95cd60 R15: ffff88801defdc40
FS:  0000000000000000(0000) GS:ffff888125390000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555708c14e8 CR3: 00000000213d2000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6250 [inline]
 kfree+0x1c5/0x640 mm/slub.c:6565
 skb_kfree_head net/core/skbuff.c:1075 [inline]
 skb_free_head net/core/skbuff.c:1087 [inline]
 skb_release_data+0x828/0xa60 net/core/skbuff.c:1114
 skb_release_all net/core/skbuff.c:1189 [inline]
 __kfree_skb+0x5d/0x210 net/core/skbuff.c:1203
 nft_synproxy_eval_v6+0x352/0x4e0 net/netfilter/nft_synproxy.c:92
 nft_synproxy_do_eval+0x3ce/0x580 net/netfilter/nft_synproxy.c:146
 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
 nft_do_chain+0x467/0x19f0 net/netfilter/nf_tables_core.c:285
 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
 nf_hook include/linux/netfilter.h:273 [inline]
 NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316
 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:540
 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6202 [inline]
 __netif_receive_skb net/core/dev.c:6315 [inline]
 process_backlog+0x7dd/0x1950 net/core/dev.c:6666
 __napi_poll+0xae/0x340 net/core/dev.c:7730
 napi_poll net/core/dev.c:7793 [inline]
 net_rx_action+0x627/0xf70 net/core/dev.c:7950
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 wg_packet_send_handshake_response+0x14d/0x310 drivers/net/wireguard/send.c:98
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:154 [inline]
 wg_packet_handshake_receive_worker+0x6a9/0x10c0 drivers/net/wireguard/receive.c:213
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/07 02:20 upstream 74fe02ce122a cbcd9ea0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in odev_release
2026/03/08 16:06 linux-next a0ae2a256046 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in odev_release
* Struck through repros no longer work on HEAD.