INFO: rcu detected stall in aoecmd_cfg (2)

Status: upstream: reported on 2026/09/21 22:20
Reported-by: syzbot+dcedecd181033573662c@syzkaller.appspotmail.com
First crash: 17d, last: 17d
▶ ▼ Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in aoecmd_cfg 1 2 770d 860d 0/3 auto-obsoleted due to no activity on 2024/12/07 10:13
linux-5.15 INFO: rcu detected stall in aoecmd_cfg (3) 1 5 16d 37d 0/3 upstream: reported on 2026/09/01 17:54
linux-5.15 INFO: rcu detected stall in aoecmd_cfg 1 1 417d 417d 0/3 auto-obsoleted due to no activity on 2025/11/25 17:18
upstream BUG: soft lockup in aoecmd_cfg (4) block prio:low 1 2 16h31m 5h04m 0/29 moderation: reported on 2026/10/08 20:17
linux-6.1 INFO: rcu detected stall in aoecmd_cfg (2) 1 1 227d 227d 0/3 auto-obsoleted due to no activity on 2026/06/03 19:48
upstream INFO: rcu detected stall in aoecmd_cfg block 1 2 2098d 2131d 0/29 auto-closed as invalid on 2021/04/09 11:08
linux-5.15 INFO: rcu detected stall in aoecmd_cfg (2) 1 2 256d 316d 0/3 auto-obsoleted due to no activity on 2026/05/05 06:23
upstream INFO: rcu detected stall in aoecmd_cfg (2) usb block 1 syz, C done 7 770d 883d 28/29 fixed on 2024/10/22 11:57
linux-6.6 INFO: rcu detected stall in aoecmd_cfg 1 1 221d 221d 0/2 auto-obsoleted due to no activity on 2026/06/09 04:24
upstream BUG: soft lockup in aoecmd_cfg (3) prio:low block 1 27 181d 526d 0/29 auto-obsoleted due to no activity on 2026/07/19 06:30
upstream BUG: soft lockup in aoecmd_cfg (2) block 1 3 675d 707d 0/29 auto-obsoleted due to no activity on 2025/03/02 19:34
upstream BUG: soft lockup in aoecmd_cfg block 1 1 994d 990d 0/29 auto-obsoleted due to no activity on 2024/04/17 16:28

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=7544/1/0x4000000000000000 softirq=37719/37720 fqs=2
rcu: 	(t=10502 jiffies g=46001 q=118 ncpus=2)
rcu: rcu_preempt kthread starved for 10499 jiffies! g46001 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:R  running task     stack:27240 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11801 Comm: syz.2.1516 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_wait_context kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:__lock_acquire+0x9d9/0x7d80 kernel/locking/lockdep.c:5087
Code: 03 42 0f b6 04 00 84 c0 0f 85 24 01 00 00 45 0f b6 24 24 45 84 e4 74 3e 0f b6 84 24 90 00 00 00 41 0f b6 cc 44 38 e0 0f 42 c8 <89> 8c 24 90 00 00 00 49 81 c6 ca 00 00 00 4c 89 f0 48 c1 e8 03 42
RSP: 0018:ffffc900001ef8a0 EFLAGS: 00000046
RAX: 0000000000000002 RBX: 0000000000000003 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911eb500
RBP: ffffc900001efae8 R08: dffffc0000000000 R09: 1ffffffff223d6a0
R10: dffffc0000000000 R11: fffffbfff223d6a1 R12: 0000000000000002
R13: ffff88802493a980 R14: ffffffff90b54e90 R15: ffff88802493a980
FS:  00007f6a10b086c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000001 CR3: 000000005faf2000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5756
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 __perf_output_begin kernel/events/ring_buffer.c:163 [inline]
 perf_output_begin_forward+0xde/0xa60 kernel/events/ring_buffer.c:273
 __perf_event_output kernel/events/core.c:7977 [inline]
 perf_event_output_forward+0x25a/0x3e0 kernel/events/core.c:7995
 __perf_event_overflow+0x461/0x660 kernel/events/core.c:9720
 perf_swevent_overflow kernel/events/core.c:9803 [inline]
 perf_swevent_event+0x319/0x570 kernel/events/core.c:9854
 perf_tp_event+0x620/0x1550 kernel/events/core.c:10381
 perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10300
 perf_trace_preemptirq_template+0x269/0x330 include/trace/events/preemptirq.h:14
 trace_irq_enable+0xbb/0xe0 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:206 [inline]
RIP: 0010:unwind_next_frame+0x1f4/0x2990 arch/x86/kernel/unwind_orc.c:494
Code: fe 00 00 00 81 40 0f 92 c5 4c 89 f7 48 c7 c6 00 00 c0 8a e8 ae d7 4b 00 49 81 fe 00 00 c0 8a 0f 93 c0 40 08 e8 4c 89 74 24 50 <0f> 85 e2 00 00 00 49 29 de 49 c1 ee 08 44 8b 2d c0 1a 6e 0b 41 8d
RSP: 0018:ffffc900001f0498 EFLAGS: 00000246
RAX: ffffffff813bb500 RBX: ffffffff81000000 RCX: ffff888024939e00
RDX: 0000000000000100 RSI: ffffffff8ac00000 RDI: ffffffff8152e17c
RBP: ffffc900001f0500 R08: ffffc900001f0630 R09: 000000000000000a
R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900001f0e40
R13: ffffc900001f0568 R14: ffffffff8152e17c R15: 0000000000000001
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
 slab_alloc_node mm/slub.c:3495 [inline]
 kmem_cache_alloc_node+0x1af/0x310 mm/slub.c:3540
 kmalloc_reserve+0x95/0x240 net/core/skbuff.c:562
 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:653
 alloc_skb include/linux/skbuff.h:1316 [inline]
 new_skb drivers/block/aoe/aoecmd.c:66 [inline]
 aoecmd_cfg_pkts drivers/block/aoe/aoecmd.c:430 [inline]
 aoecmd_cfg+0x2c5/0xa50 drivers/block/aoe/aoecmd.c:1374
 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x570/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x27d/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:generic_exec_single+0x477/0x4e0 kernel/smp.c:418
Code: 75 11 e8 2c 10 0b 00 48 85 db 75 16 e8 22 10 0b 00 eb 15 e8 1b 10 0b 00 e8 a6 cf 14 09 48 85 db 74 ea e8 0c 10 0b 00 fb 31 c0 <48> c7 44 24 20 0e 36 e0 45 4b c7 04 2c 00 00 00 00 43 c7 44 2c 08
RSP: 0018:ffffc90018557a00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000200 RCX: ffff888024939e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90018557ad0 R08: ffffffff911eb5ff R09: 1ffffffff223d6bf
R10: dffffc0000000000 R11: fffffbfff223d6c0 R12: 1ffff920030aaf44
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff920030aaf65
 smp_call_function_single+0x36d/0x5a0 kernel/smp.c:647
 task_function_call kernel/events/core.c:120 [inline]
 perf_install_in_context+0x5bb/0x920 kernel/events/core.c:2958
 __do_sys_perf_event_open kernel/events/core.c:12967 [inline]
 __se_sys_perf_event_open+0x1818/0x1d40 kernel/events/core.c:12609
 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: 0033:0x7f6a0fb9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6a10b08028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f6a0fe26090 RCX: 00007f6a0fb9e159
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480
RBP: 00007f6a0fc3506b R08: 000000000000000a R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6a0fe26128 R14: 00007f6a0fe26090 R15: 00007ffde21ed778
 </TASK>
CPU: 0 PID: 11799 Comm: syz.2.1516 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:178 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:241 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x7f/0xe0 kernel/kcov.c:346
Code: c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 8b 27 7c 7e 41 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 <41> 83 b8 24 16 00 00 00 74 cf 45 8b 98 00 16 00 00 41 83 fb 03 75
RSP: 0018:ffffc90000007390 EFLAGS: 00000246
RAX: 0000000000000008 RBX: 0000000000000000 RCX: 0000000000000003
RDX: ffffffff813bbb18 RSI: ffffffff8cfa0900 RDI: 0000000000000004
RBP: ffffc90000007538 R08: ffff88802bbd0000 R09: 0000000000000007
R10: 0000000000000009 R11: 0000000000000100 R12: ffffffff8f0e6af2
R13: ffffc900000074e8 R14: 0000000000000004 R15: dffffc0000000000
FS:  00007f6a10b296c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 000000005faf2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 unwind_next_frame+0x748/0x2990 arch/x86/kernel/unwind_orc.c:515
 __unwind_start+0x5bb/0x730 arch/x86/kernel/unwind_orc.c:760
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0xb7/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 switchdev_deferred_enqueue+0x2d/0x240 net/switchdev/switchdev.c:117
 br_switchdev_host_mdb_one net/bridge/br_switchdev.c:565 [inline]
 br_switchdev_host_mdb net/bridge/br_switchdev.c:577 [inline]
 br_switchdev_mdb_notify+0x410/0x870 net/bridge/br_switchdev.c:652
 br_mdb_notify+0x68/0x970 net/bridge/br_mdb.c:519
 br_multicast_host_leave net/bridge/br_multicast.c:1497 [inline]
 br_multicast_group_expired+0x284/0x530 net/bridge/br_multicast.c:655
 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x570/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x27d/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:generic_exec_single+0x477/0x4e0 kernel/smp.c:418
Code: 75 11 e8 2c 10 0b 00 48 85 db 75 16 e8 22 10 0b 00 eb 15 e8 1b 10 0b 00 e8 a6 cf 14 09 48 85 db 74 ea e8 0c 10 0b 00 fb 31 c0 <48> c7 44 24 20 0e 36 e0 45 4b c7 04 2c 00 00 00 00 43 c7 44 2c 08
RSP: 0018:ffffc9001841fa00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000200 RCX: ffff88802bbd0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9001841fad0 R08: ffffffff911eb5ff R09: 1ffffffff223d6bf
R10: dffffc0000000000 R11: fffffbfff223d6c0 R12: 1ffff92003083f44
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff92003083f65
 smp_call_function_single+0x36d/0x5a0 kernel/smp.c:647
 task_function_call kernel/events/core.c:120 [inline]
 perf_install_in_context+0x5bb/0x920 kernel/events/core.c:2958
 __do_sys_perf_event_open kernel/events/core.c:12967 [inline]
 __se_sys_perf_event_open+0x1818/0x1d40 kernel/events/core.c:12609
 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: 0033:0x7f6a0fb9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6a10b29028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f6a0fe25fa0 RCX: 00007f6a0fb9e159
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480
RBP: 00007f6a0fc3506b R08: 000000000000000a R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6a0fe26038 R14: 00007f6a0fe25fa0 R15: 00007ffde21ed778
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/21 22:20 linux-6.6.y 79643295eba1 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in aoecmd_cfg
* Struck through repros no longer work on HEAD.