INFO: rcu detected stall in unix_release (2)

Status: auto-obsoleted due to no activity on 2026/04/07 01:34
Subsystems: net
[Documentation on labels]
First crash: 335d, last: 214d
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ID Workflow Result Correct Bug Created Started Finished Revision
a99cabbb repro ❓ INFO: rcu detected stall in unix_release (2) 2026/03/06 18:36 2026/03/06 18:36 2026/03/06 18:49 31e9c887
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in unix_release net 1 syz, C done 1 1095d 1091d 23/29 fixed on 2023/10/12 12:48

Sample crash report:
vcan0: j1939_tp_rxtimer: 0xffff888051fff800: rx timeout, send abort
vcan0: j1939_tp_rxtimer: 0xffff888051fff800: abort rx timeout. Force session deactivation
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P12558/1:b..l P12555/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=49205, q=738 ncpus=2)
task:syz.0.1639      state:R  running task     stack:26376 pid:12555 tgid:12547 ppid:11229  task_flags:0x400040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5864 [inline]
RIP: 0010:lock_acquire+0x133/0x350 kernel/locking/lockdep.c:5825
Code: 00 65 8b 05 97 27 3f 12 85 c0 0f 85 a2 00 00 00 65 48 8b 05 d7 e5 3e 12 8b 90 ec 0a 00 00 85 d2 0f 85 8c 00 00 00 9c 8f 04 24 <fa> 48 c7 c7 69 59 f4 8d e8 70 8a fc 09 45 89 e0 89 e9 44 89 ea 65
RSP: 0000:ffffc900036c7700 EFLAGS: 00000246
RAX: ffff888051210000 RBX: ffffffff8e5c1260 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff816ae581 RDI: fffffbfff1cb824c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000093927 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
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4894
 skb_kfree_head net/core/skbuff.c:1047 [inline]
 skb_free_head+0x114/0x210 net/core/skbuff.c:1059
 skb_release_data+0x795/0x9e0 net/core/skbuff.c:1086
 skb_release_all net/core/skbuff.c:1151 [inline]
 __kfree_skb net/core/skbuff.c:1165 [inline]
 sk_skb_reason_drop+0x129/0x1a0 net/core/skbuff.c:1203
 kfree_skb_reason include/linux/skbuff.h:1275 [inline]
 unix_release_sock+0x7f4/0x1530 net/unix/af_unix.c:726
 unix_release+0x91/0xf0 net/unix/af_unix.c:1196
 __sock_release+0xb0/0x270 net/socket.c:649
 sock_close+0x1c/0x30 net/socket.c:1439
 __fput+0x402/0xb70 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ffef8ebe9
RSP: 002b:00007f8fffd23038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: 0000000000010106 RBX: 00007f8fff1c6090 RCX: 00007f8ffef8ebe9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003
RBP: 00007f8fff011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8fff1c6128 R14: 00007f8fff1c6090 R15: 00007ffc11cce118
 </TASK>
task:syz.0.1639      state:R  running task     stack:26168 pid:12558 tgid:12547 ppid:11229  task_flags:0x400140 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872
Code: e6 3e 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 22 a2 13 0f 0f 82 74 02 00 00 8b 35 da d3 13 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 79 e6 3e 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc9000417eca0 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e5c1260 RCX: 00000000f28deb84
RDX: 0000000000000000 RSI: ffffffff8de2cdb8 RDI: ffffffff8c162d80
RBP: 0000000000000002 R08: 3d5a26fa73f1642f R09: 0000000000000000
R10: 0000000000000002 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
 save_stack+0x160/0x1f0 mm/page_owner.c:156
 __set_page_owner+0x91/0x550 mm/page_owner.c:329
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2435
 shmem_alloc_folio+0x135/0x160 mm/shmem.c:1908
 shmem_alloc_and_add_folio+0x499/0xc20 mm/shmem.c:1947
 shmem_get_folio_gfp+0x67f/0x1600 mm/shmem.c:2597
 shmem_get_folio mm/shmem.c:2703 [inline]
 shmem_write_begin+0x160/0x300 mm/shmem.c:3353
 generic_perform_write+0x3c2/0x900 mm/filemap.c:4175
 shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3528
 iter_file_splice_write+0xa24/0x12e0 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x18f/0x6c0 fs/splice.c:1161
 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x174/0x240 fs/splice.c:1230
 do_sendfile+0xb06/0xe50 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ffef8ebe9
RSP: 002b:00007f8ffcdd3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f8fff1c6270 RCX: 00007f8ffef8ebe9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000008
RBP: 00007f8fff011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0001000000201005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8fff1c6308 R14: 00007f8fff1c6270 R15: 00007ffc11cce118
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10588 jiffies! g49205 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=28508
rcu: rcu_preempt kthread starved for 10589 jiffies! g49205 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:27784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 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: 1300 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:do_raw_spin_lock+0x1ce/0x2b0 kernel/locking/spinlock_debug.c:119
Code: ff df 4c 89 63 10 48 c7 44 05 00 00 00 00 00 48 8b 44 24 60 65 48 2b 05 38 9c 3e 12 0f 85 cb 00 00 00 48 83 c4 68 5b 5d 41 5c <41> 5d 41 5e c3 cc cc cc cc 48 c7 c2 08 62 42 8e 89 44 24 28 48 b9
RSP: 0018:ffffc90004a5f958 EFLAGS: 00000092
RAX: 0000000000000000 RBX: ffffffff9b115ba0 RCX: ffffffff8198133c
RDX: 1ffffffff3622b76 RSI: 0000000000000004 RDI: ffffc90004a5f900
RBP: 0000000000000293 R08: 0000000000000001 R09: fffff5200094bf20
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff9b115bb0 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881247b5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f44879d4f98 CR3: 0000000059c90000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:162
 uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
 uart_port_ref_lock drivers/tty/serial/serial_core.c:83 [inline]
 uart_write+0x13b/0xb30 drivers/tty/serial/serial_core.c:627
 handle_tx+0x204/0x630 drivers/net/caif/caif_serial.c:222
 __netdev_start_xmit include/linux/netdevice.h:5222 [inline]
 netdev_start_xmit include/linux/netdevice.h:5231 [inline]
 xmit_one net/core/dev.c:3839 [inline]
 dev_hard_start_xmit+0x94/0x740 net/core/dev.c:3855
 __dev_queue_xmit+0xa46/0x4490 net/core/dev.c:4725
 dev_queue_xmit include/linux/netdevice.h:3361 [inline]
 tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
 kthread+0x1e4/0x3e0 drivers/block/aoe/aoecmd.c:1241
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/07 10:32 upstream b236920731dd d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in unix_release
2026/01/07 01:23 linux-next 6cd6c1203113 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in unix_release
2025/11/28 17:03 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in unix_release
2025/11/28 17:00 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in unix_release
* Struck through repros no longer work on HEAD.