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INFO: rcu detected stall in clone3

Status: upstream: reported C repro on 2025/10/02 07:48
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+c6db651ad8254e5c9824@syzkaller.appspotmail.com
First crash: 67d, last: 3d03h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/12/05 linux-6.6.y (ToT) 4791134e4aeb C [report] INFO: rcu detected stall in sys_openat
2025/12/05 upstream (ToT) 2061f18ad76e C Didn't crash
▶ ▼ Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in clone3 (5) mm 1 7 343d 553d 0/29 auto-obsoleted due to no activity on 2025/03/30 08:38
upstream INFO: rcu detected stall in clone3 mm 1 2 1426d 1452d 0/29 closed as invalid on 2022/02/08 10:10
linux-5.15 INFO: rcu detected stall in clone3 1 2 124d 159d 0/3 auto-obsoleted due to no activity on 2025/11/14 02:35
upstream INFO: rcu detected stall in clone3 (2) kernfs 1 1 1274d 1274d 0/29 auto-closed as invalid on 2022/09/10 23:49
upstream INFO: rcu detected stall in clone3 (3) kernel 1 1 1023d 1023d 0/29 auto-obsoleted due to no activity on 2023/05/19 23:49
upstream INFO: rcu detected stall in clone3 (4) net mm 1 2 837d 916d 0/29 auto-obsoleted due to no activity on 2023/11/22 09:08
upstream INFO: rcu detected stall in sys_clone3 (3) mm 1 26 267d 462d 0/29 auto-obsoleted due to no activity on 2025/06/14 09:25
linux-6.1 INFO: rcu detected stall in sys_clone3 (3) 1 3 381d 440d 0/3 auto-obsoleted due to no activity on 2025/03/02 13:35
upstream INFO: rcu detected stall in sys_clone3 kernfs 1 1 1296d 1296d 0/29 auto-closed as invalid on 2022/08/20 13:01
linux-5.15 INFO: rcu detected stall in sys_clone3 1 1 430d 430d 0/3 auto-obsoleted due to no activity on 2025/01/12 11:21
upstream INFO: rcu detected stall in sys_clone3 (2) mm 1 3 560d 664d 0/29 auto-obsoleted due to no activity on 2024/08/25 02:20
linux-6.1 INFO: rcu detected stall in sys_clone3 1 1 702d 699d 0/3 auto-obsoleted due to no activity on 2024/04/15 06:45
linux-6.1 INFO: rcu detected stall in sys_clone3 (4) 1 1 243d 243d 0/3 auto-obsoleted due to no activity on 2025/07/18 19:29
linux-5.15 INFO: rcu detected stall in sys_clone3 (2) 1 1 297d 297d 0/3 auto-obsoleted due to no activity on 2025/05/25 09:12
linux-6.1 INFO: rcu detected stall in sys_clone3 (2) 1 1 562d 562d 0/3 auto-obsoleted due to no activity on 2024/09/01 21:33

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P38/1:b..l P1133/2:b..l P6446/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=15345, q=458 ncpus=2)
task:syz.2.146       state:R  running task     stack:25544 pid:6446  ppid:5936   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 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:css_tryget include/linux/cgroup_refcnt.h:44 [inline]
RIP: 0010:get_mem_cgroup_from_objcg+0xa4/0x150 include/linux/memcontrol.h:533
Code: 82 ff 49 bd 00 00 00 00 00 fc ff df 49 83 c6 10 4c 89 f5 48 c1 ed 03 42 80 7c 2d 00 00 74 08 4c 89 f7 e8 6f 32 f8 ff 4d 8b 3e <4d> 8d 67 54 4c 89 e0 48 c1 e8 03 42 0f b6 04 28 84 c0 75 16 41 f6
RSP: 0018:ffffc90005267788 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff81e4cbb9 RCX: 2db036d1d0c4fc00
RDX: 0000000000000000 RSI: ffffffff8afc6f60 RDI: ffffffff8afc6f20
RBP: 1ffff1100ba356f2 R08: dffffc0000000000 R09: 1ffffffff21b52a0
R10: dffffc0000000000 R11: fffffbfff21b52a1 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88805d1ab790 R15: ffff88807a556000
 obj_cgroup_charge_pages mm/memcontrol.c:3136 [inline]
 obj_cgroup_charge+0x346/0x620 mm/memcontrol.c:3429
 memcg_slab_pre_alloc_hook mm/slab.h:508 [inline]
 slab_pre_alloc_hook+0x2eb/0x310 mm/slab.h:719
 slab_alloc_node mm/slub.c:3477 [inline]
 kmem_cache_alloc_node+0x60/0x330 mm/slub.c:3540
 alloc_task_struct_node kernel/fork.c:174 [inline]
 dup_task_struct+0x57/0x7c0 kernel/fork.c:1116
 copy_process+0x549/0x3d70 kernel/fork.c:2331
 kernel_clone+0x21b/0x840 kernel/fork.c:2914
 __do_sys_clone3 kernel/fork.c:3215 [inline]
 __se_sys_clone3+0x252/0x2c0 kernel/fork.c:3199
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f95ac3c3e89
RSP: 002b:00007fff646159a8 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f95ac3462a0 RCX: 00007f95ac3c3e89
RDX: 00007f95ac3462a0 RSI: 0000000000000058 RDI: 00007fff646159f0
RBP: 00007f95ab9fe6c0 R08: 00007f95ab9fe6c0 R09: 00007fff64615ad7
R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8
R13: 0000000000000004 R14: 00007fff646159f0 R15: 00007fff64615ad8
 </TASK>
task:kworker/u4:6    state:R  running task     stack:23728 pid:1133  ppid:2      flags:0x00004000
Workqueue: events_unbound cfg80211_wiphy_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 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:__sanitizer_cov_trace_switch+0x7/0x120 kernel/kcov.c:330
Code: ca 77 1e 49 ff c0 4c 89 02 48 c7 44 0a 08 07 00 00 00 48 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 c3 90 f3 0f 1e fa 48 8b 06 <48> 8b 4e 08 48 83 c1 f8 48 c1 c1 3d 48 83 f9 02 7f 1e 48 85 c9 74
RSP: 0018:ffffc900049df600 EFLAGS: 00000293
RAX: 000000000000000c RBX: 0000000014abdd4b RCX: ffff888023605a00
RDX: 0000000000000000 RSI: ffffffff8d3d0de0 RDI: 0000000000000006
RBP: ffffffff8cd35180 R08: db433c9f9c316f00 R09: ffffffff81706cb9
R10: ffffc900049df6f0 R11: 1ffff110171c79e2 R12: dffffc0000000000
R13: 1ffff110046c0bcb R14: ffffffff8cd35180 R15: dffffc0000000000
 </TASK>
task:kworker/u4:2    state:R  running task     stack:23384 pid:38    ppid:2      flags:0x00004000
Workqueue: events_unbound cfg80211_wiphy_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 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:ieee80211_sta_get_rates+0xbd/0x6b0 net/mac80211/util.c:2285
Code: 79 c3 93 f7 4f 8d 34 f7 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 f7 e8 46 31 eb f7 4d 8b 3e <4d> 85 ff 0f 84 3b 05 00 00 48 8d bb 30 1c 00 00 48 81 c3 10 1d 00
RSP: 0018:ffffc90000aef778 EFLAGS: 00000246
RAX: 1ffff11005649115 RBX: ffff88802c13cc80 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 0000000000000000 R08: ffffffff8e4a93ef R09: 1ffffffff1c9527d
R10: dffffc0000000000 R11: fffffbfff1c9527e R12: ffff88802c13cc80
R13: ffff88802626c800 R14: ffff88802b2488a8 R15: ffff88802b24b348
 ieee80211_update_sta_info net/mac80211/ibss.c:1007 [inline]
 ieee80211_rx_bss_info net/mac80211/ibss.c:1122 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1613 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x1028/0x2ac0 net/mac80211/ibss.c:1642
 ieee80211_iface_process_skb net/mac80211/iface.c:1651 [inline]
 ieee80211_iface_work+0x717/0xc70 net/mac80211/iface.c:1705
 cfg80211_wiphy_work+0x225/0x260 net/wireless/core.c:437
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 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: rcu_preempt kthread starved for 10552 jiffies! g15345 f0x0 RCU_GP_INIT(4) ->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:26728 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irq+0x40/0x50 kernel/locking/spinlock.c:202
 rcu_gp_init+0x1022/0x1510 kernel/rcu/tree.c:1560
 rcu_gp_kthread+0x99/0x380 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6355 Comm: kworker/u4:15 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x17/0x90 kernel/kcov.c:313
Code: 48 89 44 11 20 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 40 21 7e 7e 65 8b 0d 41 21 7e 7e <81> e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b 83 ba 1c 16 00 00
RSP: 0018:ffffc90004d4f1f8 EFLAGS: 00000246
RAX: ffffffff813aa1d7 RBX: ffffc90004d4f228 RCX: 0000000080000000
RDX: ffff888023638000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff888023638000 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff89e5004b
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffc90004d4f228
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005630ea0b4ef8 CR3: 000000002cbb0000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 unwind_done arch/x86/include/asm/unwind.h:50 [inline]
 unwind_get_return_address+0x37/0xc0 arch/x86/kernel/unwind_orc.c:366
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0xb4/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 ieee802_11_parse_elems_full+0xb9/0x2080 net/mac80211/util.c:1616
 ieee802_11_parse_elems_crc net/mac80211/ieee80211_i.h:2337 [inline]
 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2344 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x49b/0x2ac0 net/mac80211/ibss.c:1642
 ieee80211_iface_process_skb net/mac80211/iface.c:1651 [inline]
 ieee80211_iface_work+0x717/0xc70 net/mac80211/iface.c:1705
 cfg80211_wiphy_work+0x225/0x260 net/wireless/core.c:437
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 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>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/05 16:00 linux-6.6.y 4791134e4aeb d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in clone3
2025/10/02 07:48 linux-6.6.y 147338df3487 267f56c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in clone3
* Struck through repros no longer work on HEAD.